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    Abstract: "Abrasion resistant steel plate, or steel plate excellent in stress corrosion cracking resistance, and method for producing it". The present invention relates to an abrasion resistant steel plate or sheet steel suitable for use in construction machines, industrial machines, and the like, and a method for producing them. in particular, a steel plate or steel plate excellent in stress corrosion cracking has a composition containing 0.20% to 0.30% c, 0.05% to 1.0% Si, 40% to 1.20% of mn, p, s, 0.1% or less of al, 0.01% or less of n, and 0.0003% to 0.0030% of b, on a mass basis , the composition additionally containing one or more of cr, mo, ew, the composition additionally containing one or more of nb, ti, cu, ni, v, a rem, ca, and mg as required, the remainder being fe and impurities inevitable. di * due to contained components is 45 or more. A microstructure has a base phase or main phase which is tempered martensite. Cementite having a grain size of 0.05 µm or less, in terms of equivalent circle diameter, is present on the steel plate or steel plate at 2 x 106 grain / mm2 or more. A semi-finished product having the above steel composition is heated, hot rolling is performed, air cooling is performed, reheating is performed, and accelerated cooling is then performed or accelerated, cooling is performed immediately after hot rolling.
    公开号:BR112013025040B1
    申请号:R112013025040-2
    申请日:2012-03-28
    公开日:2018-11-06
    发明作者:Keiji Ueda；Nobuyuki Ishikawa
    申请人:Jfe Steel Corporation；
    IPC主号:
    专利说明:

    (54) Title: STEEL SHEET RESISTANT TO ABRASION HAVING RESISTANCE TO FRAGILIZATION BY CORROSION UNDER TENSION, AND METHOD FOR PRODUCTION OF THE SAME (51) IntCI .: C22C 38/00; C21D 8/02; C22C 38/32; C22C 38/54.
    (30) Unionist Priority: 29/03/2011 JP 2011-071317.
    (73) Holder (s): JFE STEEL CORPORATION.
    (72) Inventor (s): KEIJI UEDA; NOBUYUKIISHIKAWA.
    (86) PCT Application: PCT JP2012059127 of 28/03/2012 (87) PCT Publication: WO 2012/133911 of 10/04/2012 (85) Date of the Beginning of the National Phase: 27/09/2013 (57) Summary: SUMMARY Patent of Invention: STEEL PLATE RESISTANT TO ABRASION, OR EXCELLENT STEEL SHEET IN RESISTANCE TO CRACKING BY TENSION CORROSION, AND METHOD FOR THE PRODUCTION OF THE SAME ”. The present invention relates to an abrasion-resistant steel plate or steel plate, suitable for use in construction machines, industrial machines, and the like, and a method for producing them. In particular, a steel plate or steel plate excellent in crack resistance by stress corrosion has a composition containing 0.20% to 0.30% C, 0.05% to 1.0% Si, 0, 40% to 1.20% of Μη, P, S, 0.1% or less of Al, 0.01% or less of N, and 0.0003% to 0.0030% of B, on a mass basis , the composition additionally containing one or more of Cr, Mo, and W, the composition additionally containing one or more of Nb, Ti, Cu, Ni, V, a REM, Ca, and Mg, as required, the remainder being Fe and unavoidable impurities. Dl * due to components contained is 45 or more. A microstructure has a base or main phase which is tempered martensite. Cementite having a grain size of 0.05 pm or less, in terms of equivalent circle diameter, is present in the steel plate or plate (...).
    1/51
    DESCRIPTION REPORT OF THE INVENTION PATENT FOR ABRASION-RESISTANT STEEL PLATES HAVING RESISTANCE TO FRAGILIZATION BY CORROSION UNDER TENSION, AND METHOD FOR THE PRODUCTION OF THE SAME.
    Technical Field [001] The present invention relates to steel plates or steel plates resistant to abrasion, having a thickness of 4 mm or more, suitable for use in construction machinery, industrial machinery, shipbuilding, steel tubes, civil engineering, architecture, and the like, and particularly refers to steel plates or steel sheets excellent in resistance to embrittlement by stress corrosion. Background of the Technique [002] In the case where hot-rolled steel plates or steel plates are used in construction machinery, industrial machinery, shipbuilding, steel pipes, civil engineering, steel structures such as constructions, machinery, equipment , or the like, the abrasion resistance property is required for such steel plates or steel plates in some cases. Abrasion is a phenomenon that occurs in moving parts of machines, appliances, or the like due to continuous contact between steel or between steel and another material, such as soil or rock, and therefore a portion of the steel surface is removed.
    [003] When the abrasion resistance property of steel is poor, machinery or equipment failure is caused, and there is a risk that the strength of structures cannot be maintained; consequently, frequent repair, or replacement of worn parts, is inevitable. Therefore, there is a strong demand for an increase in the abrasion resistance property of steel used in wear parts.
    [004] In order to allow steel to have excellent property
    Petition 870180066736, of 08/01/2018, p. 14/70
    2/51 abrasion resistance, its hardness has generally been increased. The hardness of this can be significantly increased by adopting a single-phase microstructure of martensite. The increase in the amount of carbon in the solid solution is effective in increasing the hardness of a martensite microstructure. Therefore, several steel plates and steel plates resistant to abrasion have been developed (for example, Patent Literature 1 to 5).
    [005] On the other hand, when the abrasion resistance property is required for portions of a steel plate or steel plate, in many cases, the base metal surface is exposed. The steel surface contacts water vapor, moisture, or oil containing a corrosive material, and the steel is corroded.
    [006] In the case where abrasion resistant steel is used in mining machinery including ore conveyors, soil moisture and a corrosive material, such as hydrogen sulfide, are present. In the case where abrasion-resistant steel is used in construction machinery, or the like, moisture and sulfuric oxide, which are contained in diesel engines, are present. Both cases are often very severe corrosion environments. In these cases, for corrosion reactions on the steel surface, the iron produces an oxide (rust) by an anode reaction, and hydrogen produced by the humidity cathode reaction.
    [007] In the case where hydrogen produced by a corrosion reaction permeates high hardness steel, such abrasion resistant steel, having a martensite microstructure, the steel is extremely brittle and is cracked in the presence of residual welding stress due to the operation of bending, or welding, or tension applied in the environment of use. This is embrittlement by stress corrosion. From an operational safety point of view, it is important for steel for use in machinery, equipment, or the like, to have excellent resistance to
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    3/51 abrasion and resistance to embrittlement by stress corrosion.
    Citation Lists
    Patent Literature [008] [PTL 1] Japanese Unexamined Patent Application Publication No. 5-51691 [009] [PTL 2] Japanese Unexamined Patent Application Publication No. 8-295990 [0010] [PTL 3] Japanese Unexamined Patent Application Publication No. 2002-115024 [0011] [PTL 4] Japanese Unexamined Patent Application Publication No. 2002-80930 [0012] [PTL 5] Japanese Unexamined Patent Application Publication No. 2004-162120 Non-Patent Literature [0013] [NPL 1] Standard test method for embrittlement by stress corrosion produced by the 129th Committee (The Japanese Society for Strength and Fracture of Materials, 1985), Japanese Society for the Promotion of Science Invention Technical Problem [0014] However, the abrasion resistant steels proposed in Patent Literature 1 to 5 are directed to have base material hardness, delayed fracture resistance (the above for Patent Literature 1, 3, and 4), weldability , abrasion resistance for welded portions, and corrosion resistance in condensate corrosion environments (the above for Patent Literature 5), and do not have excellent resistance to stress corrosion embrittlement, or abrasion resistance, as determined by a standard test method for corrosion embrittlement under voltage specified in Non-Patent Literature 1.
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    4/51 [0015] It is an objective of the present invention to provide an abrasion resistant steel plate, or steel plate, which is excellent in economic efficiency and excellent in resistance to stress corrosion embrittlement, and which does not cause a reduction in productivity , or an increase in the cost of production, and a method for producing it.
    Solution to the Problem [0016] In order to achieve the above objective, the inventors have intensively investigated several factors that affect the chemical components of a steel plate or steel plate, a production method, and a microstructure for the proposal to ensure excellent resistance to stress corrosion embrittlement for an abrasion resistant steel plate or steel plate. The inventors obtained the findings below.
    [0017] 1. Ensuring high hardness is essential to ensure excellent resistance to abrasion. However, an excessive increase in hardness causes a significant reduction in resistance to embrittlement by stress corrosion. Therefore, it is important to strictly control the hardness range.
    [0018] In addition, in order to intensify the resistance to embrittlement by corrosion under tension, it is effective that cementite, which acts as trap locations for diffusible hydrogen, is dispersed in a steel plate or steel plate. Therefore, it is important that the base microstructure of a steel plate or steel plate is produced from tempered martensite, in such a way that the chemical composition of the steel plate or steel plate, including C, is strictly controlled.
    [0019] The dispersion state of cementite in a microstructure of tempered martensite is appropriately controlled, so cementite is allowed to act as a trap site for hydrogen
    Petition 870180066736, of 08/01/2018, p. 17/70
    Diffusable 5/51 produced by a corrosion reaction of steel, and hydrogen embrittlement is suppressed.
    [0020] Lamination conditions, heat treatment conditions, cooling conditions, and the like, affect the dispersion state of cementite in the tempered martensite microstructure. It is important to control these production conditions. This allows grain boundary fracture to be suppressed in corrosive environments, and also allows stress corrosion embrittlement to be effectively prevented.
    [0021] 2. In addition, in order to efficiently suppress the grain boundary fracture of a tempered martensite microstructure, a measure of increasing the grain boundary strength is effective, an impurity element, such as P, needs to be reduced, and the range of Mn content needs to be controlled. Mn is an element that has the effect of intensifying the hardenability to contribute to the intensification of abrasion resistance, and that is probably to co-segregate with P in the solidification process of semi-finished products to reduce the grain contour resistance of a micro zone segregation.
    [0022] In order to efficiently suppress grain contour fracture, grain refining is effective, and the dispersion of fine inclusions having the effect aimed at suppressing grain growth is also effective. Therefore, it is effective that the carbonitrides are dispersed in the steel by the addition of Nb and Ti to it.
    [0023] The present invention was produced by further reviewing the findings obtained, and is as follows:
    [0024] 1. An abrasion resistant steel plate, or steel plate excellent in resistance to stress corrosion embrittlement, having a composition containing 0.20% to 0.30% C, 0.05% to 1, 0% Si,
    0.40% to 1.20% of Mn, 0.015% or less of P, 0.005% or less of
    Petition 870180066736, of 08/01/2018, p. 18/70
    6/51
    S, 0.1% or less of Al, 0.01% or less of N, 0.0003% to 0.0030% of B, and one or more of 0.05% to 1.5% of Cr, 0 , 05% to 1.0% Mo, and 0.05% to 1.0% W, on a mass basis, the remainder being Fe and unavoidable impurities. The abrasion-resistant steel plate or steel plate has a hardness index Dl * of 45 or more, as represented by Equation (1) below, and a microstructure having the base phase or main phase which is tempered martensite. Cementite having a grain size of 0.05 pm or less, in terms of equivalent circle diameter, is present at 2 x 10 6 grains / mm 2 or more.
    Dl * = 33.85 X (0.1 XC) 0 · 5 X (0.7 X Si + 1) X (3.33 X Mn + 1) X (0.35 X Cu + 1) X (0, 36 X Ni + 1) X (2.16 X Cr + 1) X (3 X Mo + 1) X (1.75XV + 1) X (1.5XW + 1) (1) [0025] where each symbol of alloy element represents the content (percentage of mass), and is 0 when not contained.
    [0026] 2. In the steel plate or steel plate resistant to abrasion, specified in Item 1, excellent in resistance to embrittlement by corrosion under tension, the steel composition additionally contains one or more from 0.005% to 0.025% Nb, and 0.008% to 0.020% Ti, on a mass basis.
    [0027] 3. In the steel plate or steel plate resistant to abrasion, specified in Item 1 or 2, excellent in resistance to embrittlement by corrosion under tension, the steel composition additionally contains one or more of 1.5% or less of Cu, 2.0% or less of Ni, and 0.1% or less of V, on a mass basis.
    [0028] 4. In the steel plate or steel plate resistant to abrasion, specified in any of Items 1 to 3, excellent in resistance to embrittlement by stress corrosion, the steel composition additionally contains one or more of: 0.008% or less than a REM (rare earth metal), 0.005% or less of Ca, and 0.005% or less of Mg,
    Petition 870180066736, of 08/01/2018, p. 19/70
    7/51 on a mass basis.
    [0029] 5. In addition, on the abrasion-resistant steel plate or steel plate specified in any of Items 1 to 4, excellent in resistance to stress corrosion embrittlement, the average grain size of tempered martensite is 20 m or less, in terms of equivalent circle diameter.
    [0030] 6. In addition, on the abrasion-resistant steel plate or steel plate, specified in any of Items 1 to 5, excellent in resistance to stress corrosion embrittlement, the surface hardness is 400 to 520 HBW 10 / 3000, in terms of Brinell hardness.
    [0031] 7. A method for producing an abrasion resistant steel plate or steel sheet excellent in stress corrosion embrittlement includes heating a semi-finished product having the steel composition specified in any of Items 1 to 4, 1,000Ό to 1,200Ό, performing hot rolling, reheating to Ac3 at 950Ό, performing accelerated cooling to HD / s at 100Ό, ceasing accelerated cooling to 100Ό to 300Ό, and then performing air cooling.
    [0032] 8. In the method for producing an abrasion-resistant steel plate or steel plate, specified in Item 7, excellent in embrittlement by stress corrosion, reheating to 100Ό to 300Ό is carried out after cooling with air.
    [0033] 9. In the method for producing an abrasion-resistant steel plate or steel plate excellent in stress corrosion embrittlement, it includes reheating of a semi-finished product having the steel composition specified in any of Items 1 to 4, at 1,000Ό to 1,200Ό, performing hot rolling at an temperature of Ar3 or higher, performing accelerated cooling from an Ar3 temperature to 950Ό at HD / s to 10000 / s, stopping the accelerated cooling at 100Ό to 300Ό, and r cooling
    Petition 870180066736, of 08/01/2018, p. 20/70
    8/51 air.
    [0034] 10. In the method for producing a steel sheet that is excellent in embrittlement by corrosion under stress, and that does not cause a reduction in productivity, or an increase in the cost of production. This contributes greatly to enhancing the safety and life of steel structures, and provides industrially notable effects.
    Brief Description of the Drawings [0035] [Fig. 1] Fig. 1 is an illustration showing the shape of a test specimen used in stress crack corrosion cracking.
    [0036] [Fig. 2] Fig. 2 is an illustration showing the configuration of a tester using the test specimen shown in Fig. 1.
    Description of Achievements
    Microstructure [0037] In the present invention, the base phase or main phase of the microstructure of a steel plate or steel plate is tempered martensite, and the state of a cementite present in the microstructure is specified.
    [0038] When the grain size of cementite is more than 0.05 m or more, in terms of equivalent circle diameter, the hardness of the steel plate or steel plate is reduced, its abrasion resistance is also reduced , and the effect of suppressing hydrogen embrittlement by diffusible hydrogen trap sites is not achieved. Therefore, the grain size is limited to 0.05 m or less.
    [0039] When cementite, which has the grain size above, in the microstructure, is less than 2 X 10 6 grains / mm 2 , the effect of suppressing hydrogen embrittlement by diffusible hydrogen trap sites is not achieved. Therefore, cementite in the microstructure is 2
    X 10 6 grains / mm 2 or more.
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    9/51 [0040] In the present invention, in the case of further increase in resistance to embrittlement by stress corrosion, the base phase or main phase of the microstructure of the steel plate or steel plate is made tempered martensite having a medium grain size 20 m or less in terms of equivalent circle diameter. In order to ensure the abrasion resistance of the steel plate or steel plate, a microstructure of the tempered martensite is required. However, when the average grain size of tempered martensite is greater than 20 m, in terms of equivalent circle diameter, the resistance to embrittlement by stress corrosion is deteriorated. Therefore, the average grain size of tempered martensite is preferably 20 m or less.
    [0041] When microstructures, such as bainite, pearlite, and ferrite, are present in the base or main phase in addition to the tempered martensite, the hardness is reduced, and the abrasion resistance is reduced. Therefore, the smallest area fraction of these microstructures is preferable. When these microstructures are present in them, the area ratio is preferably 5% or less.
    [0042] On the other hand, when martensite is present, the resistance to embrittlement by stress corrosion is reduced. Therefore, the smallest fraction of martensite area is preferable. The martensite can be contained because the influence of it is insignificant when the area ratio of this is 10% or less.
    [0043] When the surface hardness is less than 400 HBW 10/3000, in terms of Brinell hardness, the life of the abrasion resistant steel is short. In contrast, when the surface hardness is greater than 520 HBW 10/3000, the resistance to embrittlement by stress corrosion is noticeably deteriorated. Therefore, the surface hardness preferably ranges from 400 to 520 HBW 10/3000, in terms of Brinell hardness. Composition
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    10/51 [0044] In the present invention, in order to ensure excellent resistance to embrittlement by stress corrosion, the composition of the steel plate or steel plate is specified. In the description, percentages are on a mass% basis.
    [0045] C: 0.20% to 0.30% [0046] C is an element that is important in increasing the hardness of tempered martensite, and in ensuring excellent resistance to abrasion. In order to achieve this effect, its content needs to be 0.20% or more. However, when the content is greater than 0.30%, the hardness is excessively increased, so that the hardness and the resistance to embrittlement by stress corrosion are reduced. Therefore, the content is limited to the range of 0.20% to 0.30%. The content is preferably 0.21% to 0.27%.
    [0047] Si: 0.05% to 1.0% [0048] Si acts as a deoxidizing agent, it is necessary for steel production, and it dissolves in steel to have a hardening effect on the steel plate or plate. steel by strengthening the solid solution. In order to achieve such an effect, its content needs to be 0.05% or more. However, when the content is greater than 1.0%, weldability is impaired. Therefore, the content is limited to the range of 0.05% to 1.0%. The content is preferably 0.07% to 0.5%.
    [0049] Mn: 0.40% to 1.20% [0050] Mn has the effect of increasing the hardenability of steel. In order to ensure the hardness of a base material, the content needs to be 0.40% or more. However, when the content is greater than 1.20%, the hardness, ductility, and weldability of the base material are deteriorated, the intergranular segregation of P is increased, and the occurrence of stress corrosion embrittlement is promoted. Therefore, the content is limited to the range of 0.40% to 1.20%. The content is preferably 0.45% to 1.10%, and, more preferably, 0.45% to 0.90%.
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    11/51 [0051] Ρ: 0.015% or less; S: 0.005% or less [0052] When the P content is greater than 0.015%, P segregates at grain limits to act as the source of stress corrosion embrittlement. Therefore, the P content is up to 0.015%, and is preferably minimized. The content is preferably 0.010% or less, and more preferably 0.008% or less. S deteriorates at low temperature hardness or ductility of the base material. Therefore, the content is up to 0.005%, and is preferably low. The content is preferably 0.003% or less and 0.002% or less.
    [0053] Al: 0.1% or less [0054] Al acts as a deoxidizing agent, and is most commonly used in deoxidation processes for molten steel for steel plates or steel plates. Al has the effect of fixing N solute on steel to form AIN to suppress grain thickening, and the effect of reducing N solute to suppress deterioration of hardness. However, when its content is greater than 0.1%, the weld metal is contaminated with it during welding, and the weld cracking resistance of the base material is adversely affected. Therefore, the content is 0.0030% or less.
    [0055] One or more of Cr, Mo, W, and B [0056] Cr: 0.05% to 1.5% [0057] Cr is an element that is effective in increasing the hardenability of steel to harden the base material . In order to achieve such an effect, the content is preferably 0.05% or more. However, when the content is more than 1.5%, the hardness of the base material and resistance to cracking by welding are reduced. Therefore, the content is limited to the range of 0.05% to 1.5%.
    [0058] Mo: 0.05% to 1.0% [0059] Mo is an element that is effective in significantly increasing the hardenability to harden the base material. So
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    12/51 achieve such an effect, the content is preferably 0.05% or more. However, when the content is greater than 1.0%, the hardness of the base material, ductility, and resistance to cracking by welding, are adversely affected. Therefore, the content is 1.0% or less.
    [0060] W: 0.05% to 1.0% [0061] W is an element that is effective in significantly increasing the hardenability to harden the base material.
    [0062] In order to achieve such an effect, the content is preferably 0.05% or more. However, when the content is greater than 1.0%, the hardness of the base material, ductility, and resistance to cracking by welding, are adversely affected. Therefore, the content is 1.0% or less.
    Dl * = 33.85 X (0.1 XC) ° · 5 X (0.7 X Si + 1) X (3.33 X Mn + 1) X (0.35 X Cu + 1) X (0, 36 X Ni + 1) X (2.16 X Cr + 1) X (3 X Mo + 1) X (1.75XV + 1) X (1.5XW + 1) [0063] where each alloy element represents the content (percentage of mass), and is 0 when not contained.
    [0064] In order to produce the base microstructure of tempered martensite of base material to increase abrasion resistance, it is necessary that Dl *, which is given by the above equation, be 45 or more. When Dl * is less than 45, the hardening depth of a plate surface is below 10 mm, and the life of the abrasion-resistant steel is short. Therefore, Dl * is 45 or more.
    [0065] The above is the basic composition of the present invention, and the rest is Fe and unavoidable impurities. In the case of intensification of the effect of suppressing embrittlement by stress corrosion, one or both of Nb and Ti may be additionally contained.
    [0066] Nb: 0.005% to 0.025% [0067] Nb precipitates as a carbonitride to refine the microstructure of the base material, and an area affected by welding heat, and fixes N solute to perfect the hardness. The carbonitride is effective in competition 870180066736, from 08/01/2018, p. 25/70
    13/51 mo traps for diffusible hydrogen, and has the effect of suppressing embrittlement by stress corrosion. In order to achieve such effects, the content is preferably 0.005% or more. However, when the content is greater than 0.025%, the thick carbonitrides precipitate to act as the origin of a fracture in some cases. Therefore, the content is limited to the range of 0.005% to 0.025%.
    [0068] Ti: 0.008% to 0.020% [0069] Ti has the effect of suppressing grain thickening by forming a nitride, or by forming a carbonitride with Nb, and the effect of suppressing deterioration of hardness due to reduction of N solute. In addition, a carbonitride produced from this is effective for diffusible hydrogen trap sites, and has the effect of suppressing embrittlement by stress corrosion. In order to achieve such effects, the content is preferably 0.008% or more. However, when the content is greater than 0.020%, the precipitates are thickened and the hardness of the base material is deteriorated. Therefore, the content is limited to the range of 0.008% to 0.020%.
    [0070] In the present invention, in the case of increased resistance properties, one or more of Cu, Ni, and V may be additionally contained. Each of Cu, Ni, and V is an element that contributes to increase the strength of the steel, and is properly contained, depending on the desired resistance.
    [0071] When Cu is contained, the content is 1.5% or less. This is because when the content is greater than 1.5%, hot brittleness is caused, and therefore the surface property of the steel plate or steel plate is deteriorated.
    [0072] When Ni is contained, the content is 2.0% or less. This is because when the content is greater than 2.0%, an effect is saturated, which is economically disadvantageous. When V is contained, the content is
    0.1% or less. This is because when the content is greater than 0.1%, the
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    14/51 the base material's hardness and ductility are deteriorated.
    [0073] In the present invention, in the case of increased hardness, one or more of a REM, Ca, and Mg may be additionally contained. REM, Ca, and Mg contribute to increase hardness, and are selectively contained depending on the desired properties.
    [0074] When the REM is contained, the content is preferably 0.002% or more. However, when the content is greater than 0.008%, an effect is saturated. Therefore, the upper limit of this is 0.008%. When Ca is contained, the content is preferably 0.0005% or more. However, when the content is greater than 0.005%, an effect is saturated. Therefore, the upper limit of this is 0.005%. When Mg is contained, the content is preferably 0.001% or more. However, when the content is greater than 0.005%, an effect is saturated. Therefore, the upper limit of this is 0.005%.
    Production conditions [0075] In the description, the symbol 'C concerning temperature represents the temperature of a location corresponding to half the thickness of a plate.
    [0076] An abrasion-resistant steel plate or steel plate according to the present invention is preferably as follows: molten steel having the above composition is produced by a known steel making process, and is then formed in a steel material, such as a board or the like, having a predetermined size by continuous casting or an ingot casting laminator-roughing method.
    [0077] Then, the steel material obtained is reheated to
    1,000Ό to 1,200Ό and is then hot rolled and on a steel plate or steel plate with a desired thickness. When the reheat temperature is lower than 1,000Ό, the resistance to deformation in hot rolling is very high so that
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    15/51 the reduction by rolling per pass may not be increased; consequently, the number of rolling passes is increased to reduce rolling efficiency, and casting defects in the steel material (board) cannot be observed in some cases.
    [0078] However, when the reheat temperature is higher than 1,200Ό, surface scratches are likely to be caused by scales during heating, and a repair operation after lamination is increased. Therefore, the reheat temperature of the steel material ranges from 1,000Ό to 1,200Ό. In the case of direct hot rolling, the hot rolling of the steel material starts at 1,000Ό to 1,200Ό. The conditions for hot rolling are not particularly limited.
    [0079] In order to equalize the temperature in the hot rolled steel plate or steel plate, and in order to suppress the characteristic variations, the reheat treatment is carried out after air cooling subsequent to the hot rolling. The transformation of the steel plate or steel plate into ferrite, bainite, or martensite needs to be completed before reheating treatment. Therefore, the steel plate or steel plate is cooled to 300Ό or lower, preferably 200Ό or lower, and, more preferably, 100Ό or lower, before the reheat treatment.
    [0080] The reheat treatment is carried out after cooling. When the reheat temperature is not higher than Ac3, the ferrite is present in the microstructure, and the hardness is reduced.
    [0081] However, when the reheat temperature is higher than 950Ό, the grains are thickened, and the toughness and resistance to embrittlement by stress corrosion are reduced. Therefore, the reheat temperature is Ac3 at 950Ό. Ac3 (“C) can be dePetition 870180066736, from 08/01/2018, p. 28/70
    16/51 terminated by, for example, the following equation:
    Ac3 = 854 - 180C + 44Si - 14Mn - 17.8Ni - 1.7Cr [0082] where each of C, Si, Mn, Ni, and Cr is the content (percentage of mass) of a corresponding one of the alloying elements .
    [0083] The retention time for reheating can be short if the temperature in the steel plate or steel plate becomes uniform. However, when the retention time is long, the grains are thickened, and the hardness and resistance to embrittlement by stress corrosion are reduced. Therefore, the retention time is preferably 1 hour or less. In the case of reheating after hot rolling, the finishing temperature of hot rolling is not particularly limited.
    [0084] After reheating, accelerated cooling to a cooling stop temperature of 100Ό to 300Ό is performed at a cooling rate from HD / s to 10000 / s. Then, cooling the air to room temperature is performed. When the cooling rate for accelerated cooling is less than HD / s, ferrite, perlite and bainite are present in the microstructure, and the hardness is reduced. However, when the cooling rate is greater than 10000 / s, temperature control is difficult, and variations in quality are caused. Therefore, the cooling rate is HD / s to 10000 / s.
    [0085] When the cooling stop temperature is higher than 300Ό, ferrite, perlite and bainite are present in the microstructure, the hardness is reduced, the tempering effect of tempered martensite is excessive, and the resistance to corrosion embrittlement under stress is reduced because of reduced hardness and thickening of cementite.
    [0086] However, when the cooling stop temperature is lower than 100Ό, the martensite quenching effect is not sufficiently achieved during subsequent air cooling, the
    Petition 870180066736, of 08/01/2018, p. 29/70
    17/51 cementite morphology that is specified here is not achieved, and resistance to embrittlement by stress corrosion is reduced. Therefore, the accelerated cooling stop temperature is 100Ό to 300Ό. When the cooling stop temperature is 10OO to 300Ό, the microstructure of the steel plate or steel plate is mainly martensite, the quenching effect is achieved by subsequent air cooling, and a microstructure in which cementite is dispersed in the tempered martensite can be obtained.
    [0087] In the case where the properties of the steel plate or steel plate are equalized and the resistance to embrittlement by stress corrosion is increased, the steel plate or steel plate can be tempered by reheating to 100Ό to 300Ό after cooling accelerated. When the tempering temperature is higher than 300Ό, the reduction in hardness is significant, the abrasion resistance is reduced, the cementite produced is thickened, and the effect of diffusible hydrogen trap sites is not achieved.
    [0088] However, when the tempering temperature is lower than 100Ό, the above effects are not achieved. The retention time can be short if the temperature in the steel plate or steel plate becomes uniform. However, when the retention time is long, the cementite produced is thickened, and the effect of diffusible hydrogen trap sites is reduced. Therefore, the retention time is preferably 1 hour or less.
    [0089] In the case where reheat treatment is not performed after hot rolling, the finishing temperature of hot rolling can be Ar3 or higher and accelerated cooling can be performed immediately after finishing the rolling. When the accelerated cooling start temperature (substantially equal to the hot rolling finish temperature) is lower than Ar3, ferrite is present in the microstructure, and the hardness
    Petition 870180066736, of 08/01/2018, p. 30/70
    18/51 is reduced. However, when the accelerated cooling start temperature is 950Ό or higher, the grains are thickened, and the hardness and resistance to embrittlement by stress corrosion are reduced. Therefore, the accelerated cooling start temperature is Ar3 at 950Ό. The point of Ar3 can be determined by, for example, the following equation:
    Ar3 = 868 - 396C + 25Si - 68Mn - 21 Cu - 36Ni - 25Cr 30Mo [0090] where each of C, Si, Mn, Cu, Ni, Cr, and Mo is the content (percentage of mass) of a corresponding one alloy elements.
    [0091] The cooling rate for accelerated cooling / cooling stop temperature is the same as that for the case of reheating after hot rolling. Examples [0092] Steel planks were prepared by a continuous melting process of crucible converter refining in order to have various compositions shown in Tables 1-1 and 1-4, were heated to 950Ό to 1,250Ό, and were, in then hot rolled on steel plates. Some of the steel plates were subjected to accelerated cooling immediately after rolling. The other steel plates were cooled with air after rolling, reheated, and were then cooled with air. In addition, some of the steel plates were subjected to accelerated cooling after reheating, and were subjected to tempering.
    [0093] The steel plates obtained were investigated for microstructure, were measured for surface hardness, and were tested for hardness of base material and resistance to embrittlement by stress corrosion, as described below.
    [0094] The investigation of the microstructure was as follows: a sample for observation of the microstructure was taken from an ampliPetition 870180066736, from 08/01/2018, p. 31/70
    19/51 transversal action of 500 times the energy, using an optical microscope, five views of each sample were analyzed by image analysis equipment. The average grain size of tempered martensite was determined in terms of the equivalent circle diameter of previous austenite grains assuming that the size of the tempered martensite grains is equal to the size of the previous austenite grains.
    [0095] The investigation of the number-density of cementite in a microstructure of tempered martensite was as follows: a cross section being parallel to the direction of rolling in 1/4 of the thickness of each steel plate was photographed at a magnification of 50,000 times the energy using a transmission electron microscope, and the number of cementite was counted in ten views of each steel plate.
    [0096] The surface hardness was measured according to J IS Z 2243 (1998) in such a way that the surface hardness under a surface layer (the hardness of a surface under the surface layer; surface hardness measured after scales (layer of have been removed) has been measured. For measurement, a 10 mm rigid tungsten sphere was used and the load was 3,000 kgf.
    [0097] Three V-Charpy notch test specimens were taken from a location corresponding to a quarter of the thickness of each steel plate in a direction perpendicular to the rolling direction according to JIS Z 2202 (1998). Each steel plate was subjected to a Charpy impact test according to JIS Z 2242 (1998), and the energy absorbed at -40Ό was determined three times for each steel plate, whereby the hardness of the base material was evaluated. Those of which the average of three absorbed energies (vE-40) was 30 J or more were judged to be excellent in hardness of base material (within the scope of the present invention).
    Petition 870180066736, of 08/01/2018, p. 32/70
    20/51 [0098] A stress corrosion embrittlement test was performed according to a standard test method for stress corrosion embrittlement standardized by the 129th Committee (The Japanese Society for Strength and Fracture of Materials, 1985). Fig. 1 shows the shape of a test specimen. Fig. 2 shows the configuration of a tester. The test conditions were as follows: a test solution containing 3.5% NaCl and having a pH of 6.7 to 7.0, a test temperature of 30Ό, and a maximum test time of 500 hours. The limit stress intensity factor (Kiscc) for stress corrosion embrittlement was determined under the test conditions. The performance targets of the present invention were a surface hardness of 400 to 520 HBW 10/3000, a hardness of the base material of 30 J or more, and a Kiscc of 100 kgf / mnr 3/2 or more.
    [0099] Tables 2-1 to 2-4 show the conditions for producing the tested steel plates. Tables 3-1 to 3-4 show the test results above. It has been confirmed that the examples of the invention (Steel Plates Nos. 1, 2, 4, 5, 6, 8, 9, 11, 13 to 26, 30 and 34 to 38) meet the performance targets. However, comparative examples (Steel Plates Nos. 3, 7, 10, 12, 27 to 29, 31 to 33, and 39 to 46) cannot find any of the surface hardness, the hardness of the base material, and the cracking of 'tensile strength' corrosion, or some of the performance targets.
    Petition 870180066736, of 08/01/2018, p. 33/70
    21/51
    Comments example of the invention example of the invention example of the invention example of the invention example of the invention example of the invention example of the invention example of the invention example of the invention (percentage by mass) >H_Q zzZJ O% CD CO o CD 00 o00 o the o O CO o CD o CD CO o00 o o 1— the CD CN o CN CD O o CN ID o 5th < m o o m o o m CO o o 00 CN O o 5th CO O o O CO O o m CN O o CN ID O o ω Oo o o 0.0012 00o o o 0.0031 0.0019 0.0012 O O o 0.0013 00 O O O o CL 0.005 0.003 o o o 0.009 o o o 0.009 00 O O o o o o CD O O o £ Z CDC2 O CD o AsCD CD o CN ID o CD CD o CD o ω CO o CN CN o O CD CN o O CN ID o 00 o The CD o CD CN o O 0.224 0.253 m CN o 0.215 0.212 0.239 0.265 0.233 CN o Steel Type < 00 O Q LU LL 0 T -
    ο οCO
    22/51
    Comments example of the invention example of the invention example of the invention example of the invention example of the invention example of the invention example of the invention(percentage by mass) >the o 0.06 H 0.015 Nb0.019z 0.52 0.26 0.32 Ass 0.41 0.25 the scope of the present invention %0.1100 o Mo O0.14 0.21 0.34 0.12 0.29 Cr0.41 0.26 0.230.46< 0.042 CO o o 0.035 0.016 0.027 0.036 0.016 ω Oo o o 0.0015 o o o 0.0021 o o o 0.0021 00o o o S £o! Sω φ ω ο CL 0.002 o o o 0.005 0.009 0.003 o o o 0.012 Mn 0.53 00 CD o 0.73 O 0.63 0.74 0.92 ¢ 0 c, c 3 ώ 0.11 0.27 0.89 0.31 0.14 0.37 0.31 ω ω g O 0.291 0.236 0.210 0.243 0.273 0.207 0.247 ω c φ Steel Type "3—L 2 z O O_ Note: II
    Petition 870180066736, of 08/01/2018, p. 35/70
    23/51
    Comments example of the invention example of the invention example of the invention example of the invention example of the invention example of the invention example of the invention example of the invention example of the invention example of the invention example of the invention example of the invention example of the invention example of the invention example of the invention example of the invention Ac3 812 810 the o 00 819 819 812 820 829 00 o 00 790 0000 845 812 797 822 810 Ar3 706 713 969 726 725 733 726 740 702 0000CD 725726 669 730 707 Q 46.4 54.5 47.2 60.5 48.6 47.3 52.1 45.9 89.0 54.2 49.8 60.6 55.8 51.5 57.6 49.2 (ppm by mass) MgCN Here 20 2 LUCÉ 67 tn CD O CN25 00 00 22 CD ID 00 CD ID 20 00z 32 27 40 22 24 00 5222 CD 20 30 24 29 24 39 Steel Type < tn O Q LU LL 0 T - "3—L 2 z O O_
    Petition 870180066736, of 08/01/2018, p. 36/70
    24/51
    Comments example of the invention example of the invention example of the invention example of the invention example of the invention example of the invention example of the invention comparative example comparative example (percentage by mass) > 0.05 the othe o0.05 H 0.016 0.012 0.014o o o 0.019 0.009 the o the o _Q z 0.024 00the othe o 00 o o o0.0200.021 z 0.27 0.39 ZJ O 0.360.13 % 1 ^ o o 0.14 00 o o 0.05 O the o 0.20 00 o the o0.15 0.21 1— the 0.32 0.50 m o 0.161 ^ o o 0.58 0.28 0.22 < 0.067 o o o 0.042 0.030 0.027 0.019 0.033 0.035 0.029 ω 0.0020 0.0024 o o o o o o 0.0013 0.0012 00o o o 0.0024 0.0013 CL 0.005 o o o 0.009 o o o o o o 00 o o o 0.005 00 o o o o o o ç CO 00 o 0.82 0.62 O00 o 1.02 0.96 1.01 1.05 0.65 ω 0.24 0.33 0.31 0.17 00 o 0.22 00 o o 0.33 0.29 O 0.230 0.217 0.273 0.224 0.241 0.253 0.240 0.139 0.346 Steel Type The CÉ ω H Ξ) > % XI > l
    ο ο Í>
    cn
    25/51
    Comments comparative example comparative example comparative example comparative example comparative example comparative example(percentage by mass) > 0.05H COthe o the oOthe o0.009 Nb0.021 0.012 0.019 0.012 0.039 z 0.26Ass the scope of the present invention % 0.12 0.15 00 o o Mo0.110.32 0.11 0.26 Cr 00 o 0.32 0.270.39 0.52 < 0.035 0.027 0.025 0.031 Othe o 0.032 ω 0.0021 o o o o o o 0.0009 0.0012 Oo o o ε • s o! Sω φ ω ο Q_ 00 o o o 0.018 00 o o o 0.005 0.009 0.005 Mn N IO x — 1 0.92 0.65 00 o 0.98 0.76 u ¢ 0 c, cω ω g ώ 00 o 0.26 00 o 0000 o 0.46 00 o O 0.265 0.221 0.245 0.214 0.258 0.229 ω c φ Steel Type NI SI AB O | <l αν LUI<l Note: II
    Petition 870180066736, of 08/01/2018, p. 38/70
    26/51
    I ro φ .ω φ
    Comments example of the invention example of the invention example of the invention example of the invention example of the invention example of the invention example of the invention comparative example comparative example comparative example comparative example comparative example comparative example comparative example comparative example Ac3 CO 817 804 810 817 798 799 828 795 793 810 00 o 00 820 608 608 Ar3 715 722 705 719 710 689 692 00 CO 682 099 709 725 724 0000CD 709 Q 54.8 47.6 50.8 48.6 64.3 49.8 58.2 51.4 67.4 61.6 68.1 33.5 47.9 89.3 O (ppm by mass) Mg CN Here 20 23 2 LU cr 00 CO32 000Q CN m O CN CD 22 - O 00 CN CD O '' -l COI c *> l CO Z 34 40 27 00 CO 22 50 26 CO 27 33 44 35 28 33 42 Steel Type The cr to H Ξ) > % XI > l NI Sl AB Hi<l αν LU | <l
    Petition 870180066736, of 08/01/2018, p. 39/70
    27/51
    Comments Example of the invention Example of the invention Comparative example Example of the invention Example of the invention Example of the invention Hot Rolling Mill DC cooling rate) 1 09 1 1 1 50 Accelerated cooling stop temperatureCC) 1 150 1 1 1 100 Accelerated cooling start temperature (Ό) 1 870 1 1 1 850 Cooling method Air cooling Water cooling Air cooling Air cooling Air cooling Water cooling Finishing temperature of DC lamination) the CO 00 006 006 006 O0000 O0000 Hot Rolling TemperatureCC) 1150 1150 1150 1150 1120 1150 Plate Thickness (mm) CD CD CD CD 40 20 Material thicknessSteel (plank) (mm) 250 250 250 250 250 210 Steel Type < < < < tn O Steel Plate No. - CN COID CD
    Petition 870180066736, of 08/01/2018, p. 40/70
    28/51
    Comments Comparative example Example of the invention Example of the invention Comparative example Example of the invention Comparative example Example of the invention Hot Rolling Mill DC cooling rate) 50 50 1 1 1 Accelerated cooling stop temperatureCC) hi iol 250 1 1 100 150 1 Accelerated cooling start temperature (O) 850 840 1 1 O0000 700 1 Cooling method Water cooling Water cooling Air cooling Air cooling Water cooling Water cooling Air cooling Finishing temperature of DC lamination) the CO 00 O0000 850 850 850 750 1000 Hot Rolling TemperatureCC) 1150 1150 1100 1100 1100 1100 1220 Plate Thickness (mm) 20 20 50 50 50 50 25 Material thicknessSteel (plank) (mm) 210 210 300 300 300 300 250 Steel Type O O Q Q Q Q LU Steel Plate No.00 CD O - CN 00
    Petition 870180066736, of 08/01/2018, p. 41/70
    29/51
    Comments Example of the invention Example of the invention Example of the invention Example of the invention Example of the invention Example of the invention Example of the invention Hot Rolling Mill Cooling rate CO) 06 1 m 1 1 O00 1 Accelerated cooling stop temperatureCO) 130 1 200 1 1 200 1 Accelerated cooling start temperature (O) 790 1 820 1 1 the o 00 1 Cooling method Water cooling Air cooling Water cooling Air cooling Air cooling Water cooling Air cooling Finishing temperature of CO lamination) the coconut the o 00 840 006 O0000 850 870 Hot Rolling TemperatureCO) 1050 1150 1000 1120 1150 1100 1120 Plate Thickness (mm) - 20 30 09 20 20 50 Material thicknessSteel (plank) (mm) 200 250 300 300 250 250 300 Steel Type LL 0 T - "3—L Steel Plate No.m CD 1 ^ 00 CD 20
    Petition 870180066736, of 08/01/2018, p. 42/70
    30/51
    Comments Example of the invention Example of the invention Example of the invention Hot Rolling Mill DC cooling rate) 11 Accelerated cooling stop temperatureCC) 11 Accelerated cooling start temperature (Ό) 11 Cooling method Air cooling Air cooling Air cooling Finishing temperature of DC lamination) 820 the coconut 006 Hot Rolling TemperatureCC) 1120 1150 1150 Plate Thickness (mm) 40 20 20 Material thicknessSteel (plank) (mm) 250 250 250 Steel Type 2 z O Steel Plate No. CN 22 23
    Petition 870180066736, of 08/01/2018, p. 43/70
    31/51
    CN
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    Petition 870180066736, of 08/01/2018, p. 44/70
    32/51
    Comments Comparative example Example of the invention Example of the invention Comparative example Example of the invention Comparative example Example of the invention Tempering treatment Cooling method 1 1 1 1 1 1 1 Retention time (min) 1 1 1 1 1 1 1 Heating temperatureCO) 1 1 1 1 1 1 1 Heat treatment 1 Cooling method 1 1 Water cooling Water cooling 1 1 Water cooling Cooling rate (O) 1 1 00 00 1 1 20 Accelerated cooling stop temperatureCO) 1 1 200 200 1 1 130 Retention time (min) 1 1 20 20 1 1 m Heating temperatureCO) 1 1 850 800 1 1 006Steel Type O O Q Q Q Q LU GJ GJ _Ό θ φ g, ο ® ΌZ Q_CO CD O - CN 00
    Petition 870180066736, of 08/01/2018, p. 45/70
    33/51
    Comments Example of the invention Example of the invention Example of the invention Tempering treatment Cooling method Air cooling Air cooling 1 Retention time (min) m O 1 Heating temperatureCO) 300 150 1 Heat treatment 1 Cooling method 1 Water cooling 1 Cooling rate (O) 1 09 1 Accelerated cooling stop temperatureCO) 1 150 1 Retention time (min) 1 45 1 Heating temperatureCO) 1 840 1Steel Type LL 0 T rare _Ό θ φ g, ο ® Ό Jr Z Q_m CD
    Petition 870180066736, of 08/01/2018, p. 46/70
    34/51
    Comments Example of the invention Example of the invention Example of the invention Comparative example Comparative example Comparative example Hot Rolling Mill DC cooling rate) 75 1 1 1 1 1 Accelerated cooling stop temperatureCC) 120 1 1 1 1 1 Accelerated cooling start temperature (C) the o 00 1 1 1 1 1 Cooling method Water cooling Air cooling Air cooling Air cooling Air cooling Air cooling Finishing lamination temperature (C) 840 068 068 068 068 068 Heating temperature(Ç) 1150 1150 1150 1150 1150 1150 Plate Thickness (mm) CD 25 25 25 25 25 Material thicknessSteel (plank) (mm) 250 200 200 200 200 200 Steel Type O_ The The The The The rare _® & o 2 “73 cf Z Q 24 25 26 27 28 29
    Petition 870180066736, of 08/01/2018, p. 47/70
    35/51
    Example of the invention Comparative example Comparative example Comparative example Example of the invention Example of the invention Example of the invention Example of the invention Example of the invention Comparative example O O O O 1 m 1 1 CN 1 160 hi iol 420 150 1 130 1 1 280 1 850 840 the CD CO 960 1 840 1 1 870 1 Water cooling Water cooling Water cooling Water cooling Air cooling Water cooling Air cooling Air cooling Water cooling Air cooling 006 006 920 1000 006 006 950 O0000 006 O0000 1170 1170 1170 1170 1200 1150 1200 1100 1150 1150 the CN the CN the CN the CN 00 the CN CN CO CD O CD 220 220 220 220 250 200 250 200 300 250 CÉ CÉ CÉ CÉ ω H Ξ) > % XI the CO CO CN CO COCONUT CO m CO CD CO rCO 00 CO CD CO
    Petition 870180066736, of 08/01/2018, p. 48/70
    36/51
    Comparative example Comparative example Comparative example Comparative example Comparative example Comparative example Comparative example 1 45 1 CN 1 m 1 1 150 1 250 1 150 1 1 850 1 870 1 840 1 Air cooling Water cooling Air cooling Water cooling Air cooling Water cooling Air cooling 920 006 006 006 850 the CD 00 850 1150 1150 1180 1150 1100 1050 1100 25 20 32 40 50 30 50 250 200 250 300 300 300 300 > l NI SI AB Hi <l αν LU | <l 40 5 42 43 44 45 46
    Petition 870180066736, of 08/01/2018, p. 49/70
    37/51
    Comments Example of the invention Example of the invention Example of the invention Comparative example Comparative example Comparative example Tempering treatment Cooling method 1 1 Air cooling 1 1 1 Retention time (min) 1 1 m 1 1 1 Heating temperatureCC) 1 1 250 1 1 1 Heat treatment 1 Cooling method 1 Water-cooled Water cooling Water cooling Water cooling Water cooling DC cooling rate) 1 30 30 30 30 30 Accelerated cooling stop temperatureCC) 1 150 130 Q | c *> l 400 200 Retention time (min) 1 O O O O O Heating temperatureCC) 1 006 006 006 006 1000Steel Type CL The The The The The Ό θ φ g, ο ® ΌZ CL 24 25 26 27 28 29
    Petition 870180066736, of 08/01/2018, p. 50/70
    38/51
    Comments Example of the invention Comparative example Comparative example Comparative example Example of the invention Example of the invention Example of the invention Tempering treatment Cooling method 1 1 1 1 1 Air cooling 1 Retention time (min) 1 1 1 1 1 O 1 Heating temperatureCC) 1 1 1 1 1 200 1 Heat treatment 1 Cooling method 1 1 1 1 Water cooling 1 Water cooling DC cooling rate) 1 1 1 1 45 1 m Accelerated cooling stop temperatureCC) 1 1 1 1 100 1 150 Retention time (min) 1 1 1 1 20 1 m Heating temperatureCC) 1 1 1 1 the coconut 1 930Steel Type CÉ CÉ CÉ CÉ ω H Ξ) Ό θ φ g, ο ® Ό JrZ Q_ 30 CO 32 33 34 35 36
    Petition 870180066736, of 08/01/2018, p. 51/70
    39/51
    Comments Example of the invention Example of the invention Comparative example Comparative example Comparative example Comparative example Tempering treatment Cooling method Air cooling 1 1 1 Air cooling 1 Retention time (min) 30 1 1 1 O 1 Heating temperatureCO) 150 1 1 1 200 1 Heat treatment 1 Cooling method Water cooling 1 Water cooling Water cooling 1 Water cooling Cooling rate CO) 70 1 09 20 1 m Accelerated cooling stop temperatureCO) 150 1 200 120 1 150 Retention time (min) m 1 O m 1 m Heating temperatureCO) the coconut 1 O0000 006 1 006Steel Type > % XI > l NI SI Φ Φ _Ό θ Φ g, ο ® Ό Jr Z Q_ 37 00 CO 39 40 5 42
    Petition 870180066736, of 08/01/2018, p. 52/70
    40/51
    Comments Comparative example Comparative example Comparative example Comparative exampleTempering treatment Cooling method 1 1 1 1 Retention time (min) 1 1 1 1 Heating temperatureCC) 1 1 1 1 sides are outside the scope of the present invention Heat treatment 1 Cooling method 1 Water cooling 1 Water cooling DC cooling rate) 1 00 1 00 Accelerated cooling stop temperatureCC) 1 200 1 200 Retention time (min) 1 20 1 20 Heating temperatureCC) 1 850 1 850 l ensign italics sublinlSteel Type AB HI^ 1 av Uj | Ό θ φ g, ο ® Ό CfZ Q_ 43 44 45 46 Note: II
    Petition 870180066736, of 08/01/2018, p. 53/70
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    Comments Example of the invention Example of the invention Comparative example Example of the invention Stress corrosion embrittlement test σ5O C o £ «E * MiO) 152 111 CD CO 160 Hardness of the base material LU □ z> 82 54 59 co Surface hardness HBV10/3000 417 422 431 424 Microstructure of the steel plate Medium grain size of tempered martensite(pm) mm m Cementite number density (grain size 0.05 pm or less) (x10 8 grains / mm 2 ) 13.5 )O) §L co l < Tempered martensite area ratio (%) 100 100 O 100 Microstructure Spiced Martensite Spiced Martensite Martensita Spiced Martensite Steel Type < < < < Steel Plate No. - CN co φ-
    Petition 870180066736, of 08/01/2018, p. 54/70
    42/51
    Comments Example of the invention Example of the invention Comparative example Example of the invention Example of the invention Stress corrosion embrittlement test dogThe CO £ «E * Mi σ> m CD 77 O 192 Hardness of the base material LU □ z> 55 09 42 56 06 Surface hardness HBV10/3000 441 436 447 429 418 Steel plate microstructure Medium grain size of tempered martensite(pm) CO CO CO Cementite number density (grain size 0.05 pm or less) (x10 8 grains / mm 2 ) 21.0 9.5 §L 10.2 5.3 Tempered martensite area ratio (%) 100 100 O 100 100 Microstructure Spiced Martensite Spiced Martensite Martensita Spiced Martensite Spiced Martensite Steel Type tn O O O Q Steel Plate No. m CDCO CD
    Petition 870180066736, of 08/01/2018, p. 55/70
    43/51
    Comments Comparative example Example of the invention Comparative example Stress corrosion embrittlement test dogThe CO £ «E * Mi σ> 206 135 215 Hardness of the base material LU □ z> 52 67 22 Surface hardness HBV10/3000 368 421 324 Microstructure of the steel plate Medium grain size of tempered martensite(pm) CN m 26 Cementite number density (grain size 0.05 pm or less) (x10 8 grains / mm 2 ) 5I 3.4 S] Tempered martensite area ratio (%) 79 100 67 Microstructure Ferrita- Mar- tense weather rada Spiced Martensite Ferrita- Mar- tense weather rada Steel Type Q Q Q Steel Plate No. O - CN
    Petition 870180066736, of 08/01/2018, p. 56/70
    44/51
    Comments Example of the invention Example of the invention Example of the invention Example of the invention Stress corrosion embrittlement test O C O £ «E * MiO) 150 158 105 00 Hardness of the base material o LU □ z> 72 00 00 00 CD Surface hardness HBV10/3000 418 420 459 419 Microstructure of the steel plate Average grain size of tempered martensite (pm) 00 CDID Cementite number density (grain size 0.05 pm or less) (x10 8 grains / mm 2 ) 3.1 5.0 11.3 25.1 Tempered martensite area ratio(%) 100 100 100 100 Microstructure Spiced Martensite Spiced Martensite Spiced Martensite Spiced Martensite Steel Type LU LL 0 T GJ GJ _Ό θ φ g, ο ® ΌZ Q_ 00m CD
    Petition 870180066736, of 08/01/2018, p. 57/70
    45/51
    Comments Example of the invention Example of the invention Example of the invention Example of the invention Example of the invention Stress corrosion embrittlement test dogThe CO £ «E * MiO) 147 102 130 194 123 Hardness of the base material LU □ z> 57 37 70 97 99 Surface hardness HBV10/3000 430 510 439 403 431 Microstructure of the steel plate Average grain size of tempered martensite (pm) m - 00CN Cementite number density (grain size 0.05 pm or less) (x10 8 grains / mm 2 ) 14.9 19.4in 21.8 Tempered martensite area ratio(%) 100 100 100 100 100 Microstructure Spiced Martensite Spiced Martensite Spiced Martensite Spiced Martensite Spiced Martensite Steel Type - "3—L 2 GJ GJ _Ό O φ g, ο Φ ΌZ Q_00 CD 20 CN
    Petition 870180066736, of 08/01/2018, p. 58/70
    46/51
    Comments Example of the invention Example of the invention Example of the invention Stress corrosion embrittlement test dogO C O £ «E * MiO) 104 175 136 Hardness of the base material LU □ z> 39 CN 70 Surface hardness HBV10/3000 472 406 439 Microstructure of the steel plate Average grain size of tempered martensite (pm) m Cementite number density (grain size 0.05 pm or less) (x10 8 grains / mm 2 ) 10.9 6.3 2.6 Tempered martensite area ratio(%) 100 100 100 Microstructure Spiced Martensite Spiced Martensite Spiced Martensite Steel Type z Q O_ Φ Φ _Ό θ φ g, ο ® ΌZ Q_ 22 23 24
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    Comments Example of the invention Example of the invention Comparative example Comparative example Comparative example Stress corrosion embrittlement test dogThe CO £ «E * MiO) 158 167 m 172 65 Hardness of the base material LU □ z> 68 CD the CO 00 27 Surface hardness HBV10/3000 423 416 429 324 420 Microstructure of the steel plate Average grain size of tempered martensite (pm) CN CN CN28 Cementite number density (grain size 0.05 pm or less) (x10 8 grains / mm 2 ) m l < 10.3 §L 5I 6.6 Tempered martensite area ratio(%) 100 100 O O 100 Microstructure Spiced Martensite Spiced Martensite Martensita Bainite Spiced Martensite Steel Type The The α α σ Steel Plate No. 25 26 27 28 29
    Petition 870180066736, of 08/01/2018, p. 60/70
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    Comments Example of the invention Comparative example Comparative example Comparative example Example of the invention Stress corrosion embrittlement test C O IS «E X MiO) 177 68 m 70 103 Hardness of the base material LU □ z> 106 O CN 26 52 Surface hardness HBV10/3000 416 421 302 419 463 Microstructure of the steel plate Average grain size of tempered martensite (pm)CO m 30 CN Cementite number density (grain size 0.05 pm or less) (x10 8 grains / mm 2 ) 3.6Sl 't 3.0 Tempered martensite area ratio(%) 100 O O 100 100 Microstructure Spiced Martensite Martensita Bainite Spiced Martensite Spiced Martensite Steel Type cr cr cr cr to Steel Plate No. 30 CO 32 33 34
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    Comments Example of the invention Example of the invention Stress corrosion embrittlement test dogO C o £ «E * MiO) 155 132 Hardness of the base material LU □ z> 00 67 Surface hardness HBV10/3000 414 430 Microstructure of the steel plate Average grain size of tempered martensite (pm)O) Cementite number density (grain size 0.05 pm or less) (x10 8 grains / mm 2 ) 5.8 CD Tempered martensite area ratio(%) 100 100 Microstructure Spiced Martensite Spiced Martensite Steel Type H Ξ) Steel Plate No. 35 36
    Petition 870180066736, of 08/01/2018, p. 62/70
    50/51
    Comments Example of the invention Example of the invention Comparative example Comparative example Comparative example Stress corrosion embrittlement test dogThe CO £ «E X Mi σ> 125 106 197 50 77 Hardness of the base material LU □ z>ID 142 24 50 Surface hardness HBV10/3000 442 419 376 524 449 Microstructure of the steel plate Average grain size of tempered martensite (pm) 00 CD CN CN ID Cementite number density (grain size 0.05 pm or less) (x10 8 grains / mm 2 ) CD 21.5 2.5 15.9 8.3 Tempered martensite area ratio (%) 100 100 100 100 100 Microstructure Spiced Martensite Spiced Martensite Spiced Martensite Spiced Martensite Spiced Martensite Steel Type > % XI > l NI Steel Plate No. 37 0000 39 40 5
    Petition 870180066736, of 08/01/2018, p. 63/70
    51/51
    Comments Comparative example Comparative example Comparative example Comparative example Comparative example Stress corrosion embrittlement test dogThe CO £ «E * MiO) 62 142 160 09 CO00 Hardness of the base material LU □ z> CO CD28 22 25 Surface hardness HBV10/3000 421 00 CO 365 443 420 Microstructure of the steel plate Average grain size of tempered martensite (pm) - 2400 O Cementite number density (grain size 0.05 pm or less) (x10 8 grains / mm 2 ) CN ID 3I SI 4.3 l < Tempered martensite area ratio (%) 100 45 09 100 100 Microstructure Spiced Martensite Bainita-Martensita has perry Bainita- Marten- seasoned sita Spiced Martensite Spiced Martensite Steel Type SI AB Hi <l αν LU | <l Steel Plate No. 42 43 44 45 46
    Petition 870180066736, of 08/01/2018, p. 64/70
    1/2
    权利要求:
    Claims (5)
    [1]
    1. Abrasion-resistant steel sheet having resistance to embrittlement by stress corrosion, characterized by the fact that it has a composition containing 0.20% to 0.30% C, 0.05% to 1.0% Si, 0.40% to 1.20% of Mn, 0.015% or less of P, 0.005% or less of S, 0.1% or less of Al, 0.01% or less of N, 0.0003% to 0 , 0030% B, and one or more from 0.05% to 1.5% Cr, 0.05% to 1.0% Mo, and 0.05% to 1.0% W, in a mass base, optionally, one or more from 0.005% to 0.025% Nb and 0.008% to 0.020% Ti, in a mass base; one or more than 1.5% or less Cu, 2.0% or less Ni, and 0.1% or less V, on a mass basis; and / or one or more than 0.008% or less of a REM, 0.005% or less of Ca and 0.005% or less of Mg, on a mass basis, the remainder being Fe and unavoidable impurities, in which the resistant steel plate abrasion has a hardness index Dl * of 45 or more, as represented by Equation (1) below, and a microstructure having the base phase or main phase which is tempered martensite, in which cementite having a grain size of 0.05 pm or less, in terms of equivalent circle diameter, is present at 2 x 10 6 grains / mm 2 or more, where the average grain size of tempered martensite is 20 μm or less in terms of equivalent circle diameter, and where the surface hardness is 400 to 520 HBW 10/3000, in terms of Brinell hardness:
    Dl * = 33.85 x (0.1 x C) 0 · 5 x (0.7 x Si +1) x (3.33 x Mn + 1) x (0.35 xCu + 1) x (0, 36xNi + 1) x (2.16xCr + 1) x (3xMo + 1) x (1.75 xV + 1) x (1.5xW + 1) (1) where each alloy element symbol represents the content (percentage by mass ), and is 0 when not contained.
    [2]
    2. Method for producing an abrasion-resistant steel plate having resistance to embrittlement by stress corrosion,
    Petition 870180066736, of 08/01/2018, p. 65/70
    2/2 characterized by the fact that it comprises heating of a semi-finished product having the steel composition, as defined in claim 1, at Ί.ΟΟΟΌ to 1.20012, carrying out hot rolling, reheating to Ac3 at 950Ό, carrying out accelerated cooling to 1 Ό / s at 10OO / s, cessation of accelerated cooling to 100Ό to 300Ό, and then to perform air cooling.
    [3]
    3. Method for the production of abrasion-resistant steel plate, according to claim 2, characterized by the fact that reheating to 100Ό to 300Ό is carried out after air cooling.
    [4]
    4. Method for the production of abrasion-resistant steel sheet having resistance to embrittlement by stress corrosion, characterized by the fact that it comprises heating a semi-finished product having the steel composition, as defined in claim 1, at 1,000Ό to 1,200Ό , carrying out hot rolling at an temperature of Ar3 or higher, carrying out accelerated cooling from an Ar3 temperature to 950 ° C to 100 / s to 100 ° C / s, accelerating cooling cessation to 100Ό to 300Ό and, carrying out air cooling.
    [5]
    5. Method for producing abrasion-resistant steel plate, according to claim 4, characterized by the fact that reheating to 100Ό to 300Ό is carried out after air cooling.
    Petition 870180066736, of 08/01/2018, p. 66/70
    Details of (A)
    Saw notch: 1.5 mm
    1/1
    FIG, 1
    Fatigue notch: 1.5 mm
    TPNo.
    -O 1 r IS 15010
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    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    JPH0532462B2|1987-12-25|1993-05-17|Nippon Steel Corp|
    JPH0551691A|1991-03-11|1993-03-02|Sumitomo Metal Ind Ltd|Wear resistant steel sheet excellent in delayed fracture resistance and its production|
    FR2733516B1|1995-04-27|1997-05-30|Creusot Loire|STEEL AND PROCESS FOR THE MANUFACTURE OF PARTS WITH HIGH ABRASION RESISTANCE|
    JP4058840B2|1999-04-09|2008-03-12|住友金属工業株式会社|Oil well steel excellent in toughness and sulfide stress corrosion cracking resistance and method for producing the same|
    JP2003171730A|1999-12-08|2003-06-20|Nkk Corp|Wear resistant steel having delayed fracture resistance, and production method therefor|
    JP3736320B2|2000-09-11|2006-01-18|Ｊｆｅスチール株式会社|Abrasion-resistant steel with excellent toughness and delayed fracture resistance and method for producing the same|
    JP2002115024A|2000-10-06|2002-04-19|Nkk Corp|Wear resistant steel having excellent toughness and delayed-fracture resistance and its production method|
    JP4116867B2|2002-11-13|2008-07-09|新日本製鐵株式会社|Abrasion resistant steel with excellent weldability and wear resistance and corrosion resistance of welded parts, and method for producing the same|
    JP4645307B2|2005-05-30|2011-03-09|Ｊｆｅスチール株式会社|Wear-resistant steel with excellent low-temperature toughness and method for producing the same|
    JP4846308B2|2005-09-09|2011-12-28|新日本製鐵株式会社|High tough wear-resistant steel with little change in hardness during use and method for producing the same|
    JP4735167B2|2005-09-30|2011-07-27|Ｊｆｅスチール株式会社|Method for producing wear-resistant steel sheet with excellent low-temperature toughness|
    US7862667B2|2007-07-06|2011-01-04|Tenaris Connections Limited|Steels for sour service environments|
    JP5145805B2|2007-07-26|2013-02-20|Ｊｆｅスチール株式会社|Wear-resistant steel plate with excellent gas cut surface properties and low-temperature tempering embrittlement cracking resistance|
    JP5145804B2|2007-07-26|2013-02-20|Ｊｆｅスチール株式会社|Abrasion-resistant steel plate with excellent low-temperature tempering embrittlement cracking properties|
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    US8679265B2|2007-11-22|2014-03-25|Kobe Steel, Ltd.|High-strength cold-rolled steel sheet|
    KR101028613B1|2008-11-11|2011-04-11|신닛뽄세이테쯔 카부시키카이샤|High strength thick steel sheet and its manufacturing method|
    JP5439819B2|2009-01-09|2014-03-12|Ｊｆｅスチール株式会社|High-strength steel material with excellent fatigue characteristics and method for producing the same|
    JP2012031511A|2010-06-30|2012-02-16|Jfe Steel Corp|Wear-resistant steel sheet having excellent toughness of multi-layer-welded part and lagging destruction resistance properties|
    JP5866820B2|2010-06-30|2016-02-24|Ｊｆｅスチール株式会社|Wear-resistant steel plate with excellent weld toughness and delayed fracture resistance|JP5866820B2|2010-06-30|2016-02-24|Ｊｆｅスチール株式会社|Wear-resistant steel plate with excellent weld toughness and delayed fracture resistance|
    JP2012031511A|2010-06-30|2012-02-16|Jfe Steel Corp|Wear-resistant steel sheet having excellent toughness of multi-layer-welded part and lagging destruction resistance properties|
    WO2013065346A1|2011-11-01|2013-05-10|Ｊｆｅスチール株式会社|High-strength hot-rolled steel sheet having excellent bending characteristics and low-temperature toughness and method for producing same|
    IN2015DN00771A|2012-09-19|2015-07-03|Jfe Steel Corp|
    CN102876993A|2012-10-24|2013-01-16|章磊|High-strength corrosion-resisting steel material and manufacturing method thereof|
    JP6007847B2|2013-03-28|2016-10-12|Ｊｆｅスチール株式会社|Wear-resistant thick steel plate having low temperature toughness and method for producing the same|
    JP6235221B2|2013-03-28|2017-11-22|Ｊｆｅスチール株式会社|Wear-resistant thick steel plate having low temperature toughness and hydrogen embrittlement resistance and method for producing the same|
    CN103194688B|2013-03-28|2015-07-22|宝山钢铁股份有限公司|Wear-resistant steel pipe and manufacture method thereof|
    CN105102657B|2013-03-29|2017-03-15|杰富意钢铁株式会社|Steel and hydrogen container and their manufacture method|
    KR101546154B1|2013-10-30|2015-08-21|현대제철 주식회사|Oil tubular country goods and method of manufacturing the same|
    JP6225995B2|2013-11-22|2017-11-08|新日鐵住金株式会社|High carbon steel sheet and method for producing the same|
    KR101611011B1|2013-12-09|2016-04-08|현대자동차주식회사|Method for producing door hinge bracket|
    KR101612367B1|2014-02-17|2016-04-14|현대자동차주식회사|Non-normalized steel composition with improved material properties and the connecting rod using the same and method for manufacturing the connecting rod|
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    JP6275560B2|2014-06-16|2018-02-07|株式会社神戸製鋼所|Super high strength steel plate with excellent impact characteristics|
    EP3173764B1|2014-07-22|2021-10-06|JFE Steel Corporation|Steel sulfide-stress-cracking test method and seamless steel pipe having excellent sulfide-stress-cracking resistance|
    CN104213034A|2014-08-08|2014-12-17|安徽昱工耐磨材料科技有限公司|Low-alloy steel material and heat treatment process|
    JP6327277B2|2015-03-26|2018-05-23|Ｊｆｅスチール株式会社|High-strength hot-rolled steel sheet excellent in strength uniformity in the sheet width direction and method for producing the same|
    KR101714913B1|2015-11-04|2017-03-10|주식회사 포스코|Hot-rolled steel sheet having excellent resistance of hydrogen induced crack and sulfide stress crack for use in oil well and method for manufacturing the same|
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    CN108060362A|2017-12-21|2018-05-22|武汉钢铁有限公司|A kind of HB450 grades of anti-crack heterogeneous structure abrasion-resistant stee and its processing method|
    BR112020014081A2|2018-03-22|2020-12-01|Nippon Steel Corporation|abrasion resistant steel and method for its production|
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    CN110592477A|2019-09-16|2019-12-20|中国科学院金属研究所|Cr-rich manganese boron alloy steel and heat treatment method thereof|
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    法律状态:
    2018-05-08| B07A| Technical examination (opinion): publication of technical examination (opinion)|
    2018-09-04| B09A| Decision: intention to grant|
    2018-11-06| B16A| Patent or certificate of addition of invention granted|Free format text: PRAZO DE VALIDADE: 20 (VINTE) ANOS CONTADOS A PARTIR DE 28/03/2012, OBSERVADAS AS CONDICOES LEGAIS. |
    优先权:
    申请号 | 申请日 | 专利标题
    JP2011-071317|2011-03-29|
    JP2011071317|2011-03-29|
    PCT/JP2012/059127|WO2012133911A1|2011-03-29|2012-03-28|Abrasion-resistant steel sheet exhibiting excellent resistance to stress corrosion cracking, and method for producing same|
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