• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
  • 法律状态
  • 优先权
    • 专利摘要:
    This invention to a process for producing a plate or forging (bar, stamp work or the like), of ferrite-austenite two-phase stainless steel, containing at most 0.03 % C, at most 2.0 % Si, at most 2.0 % Mn, 25 to 35 % Cr, 6 to 15 % Ni,'at most 0.35 % N, remainder Fe and inevitable impurities with or without the addition of 0.001 to 0.030 % B with the following nickel balance value specified at -13 to -9: Ni balance value = Ni% + 0.5 Mn% + 30 x (C+N)% -1.1 (Cr% + 1.5 Si%) + 8.2 The process of the invention is characterized in that the average crystal grain size is controlled to at most 0.015 mm by heating an ingot of the above-mentioned ferrite-austenite two-phase stainless steel at a temperature of at most 1,200°C and keeping the forging ratio by hot working at a value of at least 5.
    公开号:SU1380616A3
    申请号:SU843786912
    申请日:1984-08-30
    公开日:1988-03-07
    发明作者:Кобаяси Минео；Есида Такеси；Аоки Масахиро；Охкубо Масао；Нагаяма Масааки
    申请人:Ниппон Стэйнлес Ко.,Лтд (Фирма)；Сумитомо Кемикал Компани Лимитед (Фирма)；
    IPC主号:
    专利说明:


    SP
    And it is related to the production of sheet metal or stainless steel forgings with a double phase ferrite-austenite and, in particular, ferritic-austenitic stainless steel with a dopia phase that is corrosion-resistant in the medium of asoTfioft acid.
    The aim of the invention is to increase the resistance to intergranular corrosion and to maintain a grain size of not more than 0.015 mm.
    Figure 1 shows a plot of the depth of intergranular corrosion on the average grain size of a crystal in a sheet and on the conditions for manufacturing the product; Fig. 2 is a graph of heating temperature versus phase content (austenite phase); ia fig.
    In the manufacture of sheet or forgings, stainless steels are used (c), war fa30 (1 austenite ferrite, content, wt.7,: С 0.03 or less; Si 2.0 or less; II 2 or less; Cr 25 - 35; Ni 6 - 15; N 0.35 or less and the rest of the iron and unavoidable impurities with or without additive B in an amount of 0.001 - 0.30 mass%, and having a nickel balance value, adjusted from - 13 to - 9, improves resistance to intergranular corrosion in the environment of nitric acid;
    Carbon is an effective element for the formation of austenite, however, since it forms carbide, which increases the sensitivity to intergranular corrosion, it must be contained in a small amount. Taking into account the ease of its formation, it is not necessary to set an upper limit of 0.03 May. 7.
    Silicon and manganese are elements that are used as racicants in the steelmaking process, and they usually need to be added in an amount of 2.0 wt.% Or less to simplify the production of steel on an industrial scale, therefore, the content of each element must be be limited to 2 wt.% or less.
    Chromium is an element that forms ferrite, it is important not only for the formation of a structure with a double phase of austenite and ferrite, but also to increase the corrosion resistance and wasps (1 resistance to nitric acid, therefore it is necessary to add it in quantities of 25 wt.% % or higher to achieve satisfactory resistance to nitric acid. The acid resistance of the steel increases when the chromium content increases with an appropriate balance of structure, however, when the chromium content exceeds 35 wt.%, The quality of processing is deteriorated, difficulties are created in the production of steel and the manufacture of equipment, and the use of such steel is excluded, so the upper limit of the chromium content should be 35% by weight.
    Nickel is an element that forms austenite, and, chromium, is important for the formation of a double phase structure. In addition, nickel is a very important element for reducing the rate of active dissolution, including ordinary corrosion, so it must be added in an amount of 6-15 wt.% To achieve the preferred structural balance of the ferrite austenite, respectively, to a chromium content that is It is the main ferrite forming element.
    Nitrogen, like carbon and nickel, is an effective element forming austenite, and it is also effective in increasing the corrosion resistance, for example, resistance to pitting corrosion, however, when the nitrogen content exceeds 0.35 wt.%, In the ingot a shell can form during steel production, hot working capacity is inferior, therefore, its content should be limited to 0.33 wt.% or less.
    The limit of each element satisfies the following expression
    -13 Ni balance: -9, where the value of the balance of nickel Ni d is -1.1, 2, + 0.3 Mn + -.30 - (C-t-N), Cr, 5 Si.
    When the value of nickel balance 13, the tendency to selective corrosion between the structure increases, and in such conditions it is not only impossible to improve the resistance to the effects of nitric acid, even if the chromium content does not improve, but the movement of the nickel balance towards deterioration of corrosion resistance is also accelerated corrosion. If the value of the nickel balance is above - 9, then not only is the economic disadvantage noted, since the consumption of expensive nickel increases, but the hot condition is also impaired and the corrosion resistance is deteriorated, therefore the nickel balance value is limited to - 13 to - 9.
    The effect of improving resistance to nitric acid will be noticeable if boron is added in an amount of 0.001 wt.% Or more, however, the ability to process and weld will deteriorate when its content exceeds 0.03 May. 7, therefore its content is limited to 0.001. - 0.03 wt.%
    Phosphorus and sulfur, which are impurities, are desirable when they are present in a small amount, the phosphorus content is usually acceptable in an amount of 0.040 wt.% Or less, and sulfur — 0.030 wt.% Or less. However, when the phosphorus content is limited to 0.010 wt.% Or less and sulfur is 0.005 wt.% Or less, the effect of improving the resistance to nitric acid will increase.
    An effect equivalent to a decrease in the phosphorus and sulfur content is also achieved with the addition of rare earth elements, for example. La, Ce, etc. in a small amount, for example, about 0.02 wt.%. When the heating temperature is higher than 1100 ° C or higher, the steel has a ferrite structure at about 1350 ° C. In a dual phase structure consisting of ferrite and austenite, the grain growth of the ferrite crystal is restrained by the austenite crystal grain, however, when austenite decreases in volume, this effect is weakened and the grain size of the austenite crystal increases.
    In addition, as can be seen from FIG. 2, which shows the relationship between the heating temperature and the uphase content (austenite), at a temperature of 1200 ° C or higher, the y-phase content decreases sharply, and the tendency to coarsening of grain increases dramatically therefore
    d
    5 o
    5 o
    s
    five
    Flax The upper limit of the heating temperature is 1200 C. However, in stainless steel with a double phase during hot working at 900 ° C or below, a crack is easily formed and thus the yield of the product deteriorates, therefore, it is preferable that the overheating temperature be as high as possible.
    In the process of hot treatment, it is difficult to obtain a fine-grained crystal, where the degree of deformation is small, even if the heating temperature is maintained at 1200 ° C or lower, and especially if the Hot treatment with several strains (tx to 10% or so) only creates a driving force for growth. crystal grains and, therefore, for their coarsening, therefore, the degree of deformation above the specified limits will be required. When the degree of deformation is small, the process of heating the treatment must be repeated to obtain the required overall ratio cross-section fortifications, which, on the contrary, may lead to the enlargement of crystal grains.It is difficult to obtain a common code (1) for cross-section fortification equal to 5 or more immediately after one treatment, therefore the heating and processing process must be repeated several times and In such a case, it is recommended to maintain a degree of deformation equal to 50% or higher. An industrial scale test showed that it is possible that the average grain size of a crystal can be obtained with a degree of deformation of 50% or less, for example 40%.
    Typically, the coarse-grained ingot structure is compared to the structure of the forging material and the crystal becomes fine-grained when the deformation-recrystallization cycle is repeated. The average grain size of a crystal, equal to Hbtfi of 0.015 mm or less, can reduce the depth of intergranular corrosion to 0.010 mm or less, which indicates excellent resistance to aerotic acid (figure 1). It is necessary to maintain the overall trim ratio over the ingot section at a value of 4 or higher (FIG. 3) in order to obtain an average crystal grain size of 0.015 mm or less.
    Table 1 shows the steels obtained by the proposed and comparative methods.
    Table 1
    1 Prev-P, 011 0.52 0.58 0.028 0.008 26.75 8.02 0.10
    the guy
    Example, By applying the working conditions listed in Table 2, each 1-ton ingot of the specified steels (two steel grades according to the invention and SUS 329 II and 310 ELC steel) was heated twice for each example of total crosscutting ratio and hot rolled sample (sample No. 8 was heated three times). Each sample was heated at
    Etc . for 1200
    12
    10.4D
    1050 ° C and water cooled for annealing in solid solution. Then cooked
    samples of size 3x20x30 mm (normal grinding 03) for corrosion testing for A8 h 5 times in a boiling solution containing 65% HNOj + Cr (100 ppm), and then in depth
    intergranular corrosion was measured intergranular corrosion activity in an environment of nitric acid.
    I
    Table 2
    7.60 0.012 0.009 according to
    to the invention
    7/70
    0,007 0,009
    1250
    1200
    1200
    1250
    1200
    7: 600,0300,018
    3 7,700,0220,016
    6 600,0130,008
    11, 0080,010
    , 0270,019
    5 DO0,0200,015
    (heated three times)
    Compare - 1200
    calf
    the way
    1200
    Figure 1 shows the result of testing samples No. 1-4. As can be seen from figure 1, the depth of intergranular corrosion and the grain size of a crystal are interconnected, and with an average grain size less than 0.015 mm, the depth of intergranular corrosion will decrease, providing excellent resistance to corrosion in the environment nitric acid. As shown in Table 1, corrosion resistance cannot be improved with a total forging ratio over a cross section of 7 or more when the heating temperature is 1250 ° C or more, therefore, treatment should be carried out at 1200 C or lower, and the improvement of resistance to intergranular corrosion it becomes difficult if the treatment is carried out at 1200 ° C or lower, with a total forging ratio over a cross section of 3. In addition, the formation of fine
    g 60
    0.012 0.018 Mark
    SUS329JI
    470
    0.1VO 0.100
    Brand 310 ELC

    the grain is not enough to obtain a satisfactory corrosion resistance even at a heating temperature of 1200 ° C and a total forging ratio over section 5, if the degree of deformation during each heating is less than 40%. Also, resistance to intergranular corrosion cannot be improved in SUS 329 L and 310 ELC steel, using the proposed treatment method.
    权利要求:
    Claims (1)
    [1]
    The invention The method of manufacturing a sheet or forgings of stainless ferritic-austenitic steel, mainly containing (wt.%) Not more than 0.03 carbon, not more than 2.0 silicon, not more than 2.0 manganese, 25 - 33 chromium, 6 -15 nickel, no more than nitrogen, no more than 0.01 of phosphorus, no more than 0.005 sulfur.
    the rest is iron, including heating to 1200 ° C and deformation at this temperature, characterized in that, in order to increase the resistance to intergranular corrosion by
    About SAMPLE N0.1 SAMPLE NQ.2 SAMPLE N0.3 SAMPLE N0.
     1 / fO 4
     I §
    t;
    se
    OS
    QC with
    Vo
    cv:
    five
     "
    t
    2J
    AVERAGE CRYSTAL Figure 1
    maintaining a grain size of no more than 0-15 mm; deformation is carried out by rolling with a total degree of at least 50% or by forging with a total degree of shortening of at least 5.
    4i / w
    & RAIN SHE, mm
    900 fpuz.Z
    WOO
    o.o
    Ijj kj
    0.02
    0
    Thebes. J
    LOO} 200 1300
    HE / IT ING JinPERftJURE C
    6W
    FORGING MTIO
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    同族专利:
    公开号 | 公开日
    US4659397A|1987-04-21|
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    EP0138012A2|1985-04-24|
    JPS6367523B2|1988-12-26|
    EP0138012B1|1993-03-31|
    EP0138012A3|1988-07-06|
    JPS6052523A|1985-03-25|
    DE3486117D1|1993-05-06|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    US2073901A|1930-05-29|1937-03-16|Babcock & Wilcox Tube Company|Austenitic ferrous alloys and articles made thereof|
    US3519419A|1966-06-21|1970-07-07|Int Nickel Co|Superplastic nickel alloys|
    AT333819B|1973-12-10|1976-12-10|Ver Edelstahlwerke Ag|AUSTENITIC-FERRITIC CHROME-NICKEL-NITROGEN-STEEL|
    DD134246A1|1977-12-05|1979-02-14|Eckstein Hans Joachim|NON-LOADING STEEL WITH IMPROVED CORROSION, FORMAT AND SLIP PROPERTIES|
    DE2815439C3|1978-04-10|1980-10-09|Vereinigte Edelstahlwerke Ag , Wien Niederlassung Vereinigte Edelstahlwerke Ag Verkaufsniederlassung Buederich, 4005 Meerbusch|Use of a ferritic-austenitic chrome-nickel steel|
    JPS5946287B2|1979-02-13|1984-11-12|Sumitomo Metal Ind|
    JPS5715660B2|1979-09-14|1982-03-31|
    JPS5914099B2|1980-04-04|1984-04-03|Nippon Yakin Kogyo Co Ltd|
    JPS6045251B2|1981-05-22|1985-10-08|Sumitomo Metal Ind|
    JPS6036466B2|1981-08-20|1985-08-20|Nippon Sutenresu Kk|
    JPH0254404B2|1982-08-24|1990-11-21|Kawasaki Steel Co|
    JP5644757B2|2011-12-28|2014-12-24|株式会社日本自動車部品総合研究所|Pressure control device|
    JP5935620B2|2012-09-18|2016-06-15|株式会社村田製作所|Flat cable|US4721600A|1985-03-28|1988-01-26|Sumitomo Metal Industries, Ltd.|Superplastic ferrous duplex-phase alloy and a hot working method therefor|
    US4828630A|1988-02-04|1989-05-09|Armco Advanced Materials Corporation|Duplex stainless steel with high manganese|
    US5201583A|1989-08-17|1993-04-13|British Technology Group Limited|Temperature history indicator|
    GB8918774D0|1989-08-17|1989-09-27|Nat Res Dev|Temperature llistory indicator|
    SE501321C2|1993-06-21|1995-01-16|Sandvik Ab|Ferrite-austenitic stainless steel and use of the steel|
    NL1014512C2|2000-02-28|2001-08-29|Dsm Nv|Method for welding duplex steel.|
    WO2009017258A1|2007-08-02|2009-02-05|Nippon Steel & Sumikin Stainless Steel Corporation|Ferritic-austenitic stainless steel excellent in corrosion resistance and workability and process for manufacturing the same|
    JP5511208B2|2009-03-25|2014-06-04|新日鐵住金ステンレス株式会社|Alloy-saving duplex stainless steel material with good corrosion resistance and its manufacturing method|
    JP6308869B2|2014-05-27|2018-04-11|新日鐵住金ステンレス株式会社|Ferritic stainless steel wire excellent in formability and pitting corrosion resistance and method for producing the same|
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    法律状态:
    优先权:
    申请号 | 申请日 | 专利标题
    JP58161087A|JPS6367523B2|1983-09-01|1983-09-01|
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