• 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:
    The invention relates to a method for producing an assembly of a first sintered component and a further sintered component or a component made of solid material, wherein the sintered or the components are made of an iron-based sintered material, in particular steel, and the component made of solid material of an iron-based material is, in particular steel, wherein further in the first and optionally second sintered component prior to bonding with each other or with the component made of the solid material, the carbon content is increased by carburizing, and wherein before bonding at least in the first sintered component, a layer with increased carbon content at least in the Joint is removed. Before carburizing, the region to be carburized, in particular the entire sintered component, is at least partially provided with a diffusion barrier for the carbon.
    公开号:AT513429A1
    申请号:T1026/2012
    申请日:2012-09-20
    公开日:2014-04-15
    发明作者:
    申请人:Miba Sinter Austria Gmbh；
    IPC主号:
    专利说明:

    • «• 1 · ♦ · ··
    The invention relates to a method for producing an assembly from a first sintered component and a further sintered component or a component from solid material, wherein the sintered component (s) are manufactured from an iron-based sintered material, in particular steel, and the component is made of the solid material from an iron-based material, in particular steel, wherein the carbon content is further increased by carburizing in the first and optionally second sintered component prior to bonding with each other or with the component made of the solid material, and wherein before joining at least in the first sintered component removed a layer with increased carbon content at least in the region of the connection point becomes.
    In the case of iron-based components which are welded together to produce a larger assembly, the lowest possible carbon equivalent should be present in the connection region, since otherwise the components have poor weldability.
    The carbon equivalent is a measure in material science for assessing the weldability of unalloyed and low-alloyed steels. The carbon content and a variety of other alloying elements in the steel affect its behavior. In order to assess the weldability, the carbon equivalent and the weighted proportion of the elements which influence the weldability of the steel in a similar way as would be expected from carbon are therefore summarized in a numerical value in the carbon equivalent. A value of the carbon equivalent of less than 0.45% implies good weldability. Higher values require, depending on the processing thickness, the preheating of the material, although this does not always lead to the desired result. From ei-2/24 N2012 / 16700
    With a value greater than 0.65, the workpiece is suitable for welding only with increased effort since it can lead to cold or hardening cracks due to martensite formation.
    Case hardening of steel components made of solid material or a sintered material by means of carburization is a common method to improve the mechanical characteristics of such components. In case hardening, carbon is introduced into the material in the near-surface regions, a concentration gradient being formed over the layer thickness. Although this procedure is fundamentally the same for solid material components, ie, forged components, for example, and sintered components, the result achieved differs markedly. The reason for this is that due to the porosity of sintered components, the carbon diffuses into them much faster than in solid material components. This results in differences in fatigue strength, since due to the faster diffusion of the carbon whose concentration gradient is flatter.
    In case hardened steel components, to improve weldability, usually the surface layer with the increased carbon content in the weld area is mechanically removed.
    In sintered components, however, this method leads only to a limited extent to the desired result, since, as stated above, the carbon penetrates very deeply into the sintered components and thus a very large layer thickness would have to be removed in order to strike a layer with a lower carbon content. This in turn leads to a decrease in the load capacity of the module.
    It is therefore the object of the invention to improve the weldability of case-hardened sintered components for the production of an assembly.
    This object is achieved by the method mentioned above, in which, prior to carburizing, the region to be carburized, in particular the entire sintered component, is at least partially provided with a diffusion barrier for the carbon. 3/24 N2012 / 16700 • ··········································································
    The advantage here is that the diffusion barrier prevents the carbon in the subsequent carburization step from entering deeper layers, i. also penetrate the core zone or the carbon content in the core zone is significantly reduced. It is thus a sintered component to produce, in which a significant concentration jump with respect to the carbon at the transition from the edge zone into the core zone of the sintered component can be formed. Accordingly, a sintered component produced by the method may have a hard outer martensitic layer and a perlitic-ferritic core zone which is soft in comparison thereto. With such a pronounced jump in the carbon concentration, a hardness gradient can be generated, which is produced by a sudden transition from the martensitic to the equilibrium structure. It can thus be limited to a relatively small marginal zone, the high carbon content, which can be removed for the production of the assembly, without the mechanical characteristics of the assembly are significantly deteriorated by this material weakening. As a side effect, it is thus possible to improve the dynamic behavior of the sintered component in comparison with sintered components known from the prior art.
    The diffusion barrier is preferably produced by oxidation from the material of the component itself. It is thus a corresponding process simplification achievable, since no additional materials must be applied to the sintered component. In addition, the entry of foreign substances and, as a consequence, a possible change in the property profile of the sintered component, which can also only occur during use by means of different phase transformations, can thus be better avoided. However, a significant advantage is that the oxides are at least partially reduced again during carburization by the carbon which diffuses in, as a result of which this carbon is consumed and thus the penetration depth of the carbon can be reduced due to an excessively high diffusion rate or the concentration jump at the boundary surface between the edge zone and the core zone can be made more pronounced. 4/24 N2012 / 16700
    According to the preferred embodiment of the method, the oxidation is carried out with steam.
    Currently, the steam oxidation is used as a post-treatment process to achieve an improvement in the use value of sintered molded parts.
    It is used both for increasing corrosion and wear resistance. Likewise, an increase in hardness of the component, a modified appearance, a better layer adhesion of subsequently applied layers and increased tightness of the components can be adjusted. The elongation at break of only steam-treated components, however, decreases by about 50%.
    The steam treatment has in the method according to the invention the advantage that it can be used on an already known and frequently used technology, so that no significant changes in terms of the equipment must be made to carry out the process.
    For the same reasons, the oxidation is preferably carried out at a temperature between 400 ° C and 800 ° C, in particular between 550 ° C and 620 ° C.
    It is also possible that the oxidation is combined with a burn off process. It can thus be made more efficient in the production of the sintered component, by removing impurities from the sintering process itself at the same time as the oxidation. As a side effect can occur that the oxide compounds formed during the Abbrennprozesses can also serve as a diffusion barrier.
    For a better understanding of the invention, this will be explained in more detail with reference to the following description.
    The production of sintered components per se is sufficiently described in the prior art, so that in the following only a brief outline of a possible embodiment variant of a sintering process is given. 5/24 N2012 / 16700
    In essence, the manufacture may include the steps of powder blending, pressing, dewaxing and sintering. Optionally, the sintering can be followed by a thermal aftertreatment and / or a mechanical post-processing. 1) powder mixing
    The iron powder mixtures used can total up to 10 wt .-%, metallic non-ferrous alloying elements, optionally up to 5 wt .-% carbon in the form of graphite, up to 3 wt .-% pressing aid and up to 0.5 wt. - Have% organic binder. These mixtures are conventionally prepared, for example, from pure iron powder or pre-or alloyed iron powders as base material and addition of alloying elements and pressing aids. Or so-called mother mixture in highly concentrated form, optionally also with the use of temperature and / or solvents, premixed and then mixed with iron powder or mixed by adding the individual components directly into the iron powder.
    As binders resins, silanes, oils, polymers or adhesives can be used. Pressing aids are i.a. Waxes, stearates, silanes, amides, polymers.
    Pre-alloying elements may be Mo, V, Si, Mn.
    By further non-ferrous alloying elements, such as. Chromium, copper, nickel, manganese, silicon, molybdenum and vanadium, the properties of such iron-based powder sintered components can be improved accordingly, as is already known from the prior art for steels. Thus, e.g. By alloying molybdenum, the temper brittleness of chromium steels is avoided. It will improve the hardenability and toughness. In addition, the creep resistance can be increased at higher temperatures. Nickel can improve cold workability. With manganese, the tensile strength and the yield strength can be improved. With the help of silicon, the precipitation of cementite from the martensite can be prevented during tempering. 6/24 N2012 / 16700
    Since the principal effect of these alloying elements is known per se from the prior art, a further discussion at this point is unnecessary.
    The proportion of non-ferrous alloying elements may also be selected from a range with a lower limit of 0.2% by weight and an upper limit of 8% by weight, in particular from a range with a lower limit of 1% by weight. and an upper limit of 6% by weight.
    Typical mixtures are, for example: Fe (pre-alloyed with 0.85% by weight of Mo) + 0.1% by weight - 0.3% by weight of C + 0.4% by weight - 1.0% by weight % Pressing aid and possibly binder Fe + 1% by weight 3% by weight Cu + 0.5% by weight 0.9% by weight C + 0.3% by weight 0.8 % By weight of pressing assistant and possibly binder. Astaloy CrM (Cr + Mo prealloyed iron powder) + 1% by weight - 3% by weight of Cu + 0.1% by weight -1% by weight of C + 0.3 Wt .-% -1.0 wt .-% pressing aid and possibly binder.
    However, it is also possible to use all other compositions customary in sintering technology.
    Suitable mixtures are, for example: 18% by weight Mn + 2.5% by weight Al + 3.5% by weight Si + 0.5% by weight V + 0.3% by weight B, remainder Fe or 24% by weight Mn + 3% by weight Al + 2.5% by weight Si, remainder Fe or 14% by weight Mn, 5% by weight Ni + 3% by weight Al + 3% by weight % Si, balance Fe.
    These mixtures are mixed with corresponding mixing methods of powder metallurgy and homogenized. It is also possible to use the 7/24 N2012 / 16700 • • • • • • • • • • • • • • • • • • • • • • • • • • • • •
    Technique known binder process technology or the known process of diffusion alloying for uniform distribution of especially fine powder portions to use. 2) pressing
    The iron powder mixtures pretreated by the above-mentioned method can be compacted and shaped by coaxial pressing methods. It must be ensured that the shape and shape changes resulting during the subsequent process steps are already taken into account in the production of the pressing tools. The use of appropriate lubricants and binders aids in compaction. Depending on the bulk density and theoretical density of the powder mixtures, compression pressures of 400 MPa to 1200 MPa are used for this purpose.
    The compacts obtained in this way (also called green compact) are the output for the subsequent process steps.
    Instead of the coaxial pressing methods, other pressing methods can be used, as are customary in sintering technology, e.g. also isostatic pressing, etc ..
    In order to achieve reproducible dimensional behavior during sintering, care must be taken during pressing to ensure the most uniform or at least highly reproducible density distribution within the sintered component. Since a liquid phase can form during sintering (depending on the process conditions and composition of the pressed powders), it is advantageous to select the density at which the density distribution which is as uniform as possible can be achieved. Typical densities are therefore 6.4 g / cm 3 - 6.6 g / cm 3, but can also be chosen higher depending on the chemical composition and compressibility of the powder. 8/24 N2012 / 16700 • · «· · · · · · ·« t I · Φ · · · I I · · Φ I φ | • <g · * · * φφ • · • · • »
    The optionally required lubricants can be applied to the component either by conventional dipping methods or preferably by means of spraying prior to or during the pressing. 3) Dewaxing + sintering
    The pellets may be dewaxed by thermal treatment, preferably under the action of at least partially carburizing or slightly oxidizing atmospheric gases, i. be at least partially freed from burnout by the organic binder and lubricants (unless this is in a subsequent process step, as will be explained below) and sintered, preferably in continuous sintering furnaces. In this case, reducing atmospheres are achieved by using nitrogen-hydrogen mixtures with up to 30 vol .-% hydrogen content. Optionally carburizing gases, e.g. Methane, propane, or the like can be used or by slightly oxidizing character of the process gas (optionally only in sections of the sintering furnace), the dewaxing be supported, for example by endogas, humidified nitrogen, or the like. The sintering can also be carried out under vacuum, whereby a stabilization of the liquid phase can be achieved during sintering.
    The temperatures during sintering are between 1050 ° C and 1350 ° C depending on the alloy system used, the sintering holding time is between about 2 minutes and 1.5 hours.
    The process control during sintering is selected so that the smallest possible component distortion results in the event of any liquid phase. The reproducibility of the result is supported by appropriate process control, such as atmosphere control, temperature control, dew point measurement, etc.
    The sintered member is preferably cooled at a cooling rate selected from a range having a lower limit of 0.5 K / s, more preferably 1 K / s, and 20 K / s, preferably 15 K / s. 9/24 N2012 / 16700 ·· &lt; · 9 • * * • • * * • • • • • «9 9 · • • &gt; •••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••• 9
    Optionally, in order to achieve higher densities, the compacts are also pre-sintered by thermal treatment at a temperature of below 1100 ° C under the action of the above-mentioned reducing atmospheric gases and possibly re-pressed, in particular outgrown at the same time. It can thus be achieved the production of a light sintered bond between the particles. 4) Thermal aftertreatment
    Various heat treatments known in the art are applicable. Thermal processes can be used to change the ratio of ferrite to perlite constituents. 5) Mechanical processing
    All known methods of mechanical finishing or coating are possible.
    To improve the mechanical properties of such iron-based sintered components, these are usually cured after sintering, for example case-hardened. In case hardening, the proportion of carbon on the sintered component in the area of the surface as well as in near-surface layers is increased by carburizing. According to the method according to the invention, it is now provided that a diffusion barrier for the carbon is applied or formed before hardening on or in the sintered component. It is thus achieved an increase in fatigue properties in case hardened sintered moldings. The fatigue strength increase can be created by introducing a high carbon and hardness gradient.
    It should be noted that by a high carbon gradient is meant a concentration gradient of carbon, where the concentration is precipitous, i. in the range of a layer thickness between 400 pm and 1500 pm to 10/24 N2012 / 16700 ······················································································ At least 80% of the initial concentration on the surface of the sintered component decreases. Along with this, a high hardness gradient is formed, wherein the hardness decreases over this layer thickness range by 80% based on the hardness at the surface of the sintered component.
    In general, the carbon diffuses very quickly through the pore channels during case hardening of sintered components or sintered components and can thus penetrate deep into the component in a short time. By introducing a diffusion barrier, the penetration rate of the carbon can be reduced.
    As diffusion barrier can be applied, for example, a copper-based masking paste, for example by brushing, spraying or dipping the sintered component (s).
    However, in the preferred embodiment, the diffusion barrier is made from the sintered component itself, i. the material of the sintered component, formed.
    Particularly preferably, the iron is oxidized, in particular to magnetite (Fe304). In particular, this oxidation can be carried out with steam.
    The pre-switching of a "steaming process" before the carburizing operation causes the formation of a magnetite (Fe304) layer on the sintered component and / or in the pores of the sintered component, i. in the water vapor-treated surface areas, and thus can provide a diffusion barrier. The carbon must reduce the oxide layer before it enters the iron particles. Thus, the rate of diffusion of the carbon slows down and the penetration depth of the carbon atoms decreases. Accordingly, only at the edge of the component, d. H. in the boundary layer, a martensitic zone, the component interior, i. the core zone retains the original equilibrium structure. The stronger the hardness gradient is formed, the higher the fatigue strength of the component. It can be achieved with this method Zahnfußfestigkeiten which exceed 880 MPa (ofo.öo measured according to DIN 3990).
    In the steam treatment, the iron sintered material is heated in an atmosphere of steam and nitrogen, so that according to 11/24 N2012 / 16700 11
    3 Fe + 4 H20 Fe304 + 4 H2 on the water vapor accessible surface (also in the open pores) a dense, blue-black reaction layer of magnetite (Fe304) is formed, which closes the pore channels with increasing thickness. Their formation speed decreases with the shift increase. The temperature of the steam treatment may be between 400 ° C and 800 ° C, in particular between 500 ° C and 700 ° C, for example at 600 ° C.
    The time for the oxidation by means of steam is preferably selected from a range of 60 minutes to 420 minutes, in particular from a range of 90 minutes to 200 minutes.
    Preferably, the steam oxidation, i. this pre-oxidation process, used in a continuous process in which the finished sintered sintered components are transported on a belt through the water vapor or water vapor-containing atmosphere. The belt speed, which likewise influences the layer thickness of the oxide layer formed, like the temperature or the duration of the oxidation, can be between 25 mm / min and 80 mm / min, in particular between 30 mm / min and 80 mm / min. It is therefore possible with these parameters to regulate and / or control the oxidation process, in particular the layer thickness of the oxide layer formed. Subsequently, this layer thickness has effects on the formed concentration gradient, as will be explained below.
    As an additional parameter, the water vapor content of the oxidation atmosphere can be used. This proportion of water vapor in the oxidizing atmosphere may be between 75% by volume and 90% by volume, in particular between 80% by volume and 90% by volume, preferably between 85% by volume and 90% by volume, be. The remainder to 100 vol .-% forms in each case air. In particular, a volume conversion of water vapor between 40 kg / h and 100 kg / h, preferably between 75 kg / h and 90 kg / h. 12/24 N2012 / 16700 12 * · • · • · • ·
    Instead of steam, the oxidation can also be carried out with carbon dioxide or air or oxygen or mixtures thereof or with water vapor.
    By a long time of the oxidative treatment and / or by the application of a high reaction temperature and / or a high proportion of oxidant and / or a low belt speed, a relatively high layer thickness of iron oxide is achieved, and vice versa. But it is also possible that, for example, a high temperature and a high belt speed for adjusting the layer thickness is used.
    This listing of setting options of the oxidation is not conclusive. Rather, it is merely intended to show that the layer thickness of the oxide layer to be formed can be adjusted by various combinations - and consequently the strength of the carbon gradient or of the hardness gradient can subsequently be adjusted.
    The layer thickness of the oxide layer is preferably between 1 pm and 5 pm, in particular between 2 pm and 4.5 pm.
    It should be noted at this point that the oxide layer is not necessarily complete, i. continuous, must be formed, but also areas with no or a thinner oxide layer in the context of the oxidation process are allowed, although in view of a uniform as possible carburizing as uniform as possible layer thickness over the entire surface to be carburized is preferred.
    After this oxidation process, the sintered component is fed to the case hardening. Case hardening can be carried out, for example, as carburizing or carbonitriding. Both methods are well known in the art. This increases the carbon content in the surface layer.
    For this purpose, the steam-treated sintered components are exposed to a reducing atmosphere in a carburizing unit. The gas composition is controlled by methanol and nitrogen. The proportion of methanol can be selected from a range from 50% by volume to 80% by volume, in particular from a range from 50% by volume to 70% by volume. , The proportion of nitrogen can be selected from a range of 20 vol .-% to 50 vol .-%, in particular from a range of 35 vol .-% to 45 vol .-%. For example, a composition of 40% H2, 40% N2, 20% CO is used.
    Other gases can also be used, for example endogas (mixture of natural gas and atmospheric oxygen).
    When carburizing, i. The iron oxide layer, in particular the magnetite layer, on the component surface as well as on the inner surfaces of the open porosity is believed to increase the carbon content in the boundary layer of the sintered component
    Fe304 (s) + 2 CO + 2H2 (g) * 3 Fe (s) + 2 CO (g) + 4 H20 (g) reduced. The carbon from the atmosphere therefore slowly decomposes the oxide and can then diffuse into the iron grains. Since the carbon must work at low speed, homogeneity throughout the batch can be ensured due to the consistent or somewhat shortened process time.
    The process time of the carburizing can be between 60 minutes and 640 minutes, in particular between 60 minutes and 350 minutes.
    The temperature of the carburizing can be between 800 ° C and 1000 ° C, in particular between 830 ° C and 950 ° C, preferably between 850 ° C and 900 ° C.
    By varying the carburizing temperature and the carburizing time, the depth of the mar-tensitic boundary zone can be controlled. The diffusion speed or the diffusion coefficient increases exponentially with the temperature and with the root of the 14/24 N2012 / 16700 14 14
    • · · · · · · · · · ·
    Time on. Thus, it can be estimated how far the carbon can penetrate into the component.
    The carburizing can be carried out as pure carburization. However, it is also possible during the carburization to introduce other elements or to enrich the sintered component with at least one further element, for example, to carry out a carbonitriding.
    By introducing the diffusion barrier is achieved in the subsequent carburizing of the sintered component as forged a strongly demarcated, martensitic edge zone. With a strong hardness gradient, which is due to a sudden transition from the martensitic to the equilibrium structure, i. is produced in a pearlitic-ferritic microstructure, the dynamic performance can be increased, since thus the sintered components on the one hand have a hard edge layer and on the other hand a relatively soft core zone. In the case of sintered components, which are produced without the formation of the diffusion barrier prior to carburization, that is to say in particular without an oxidation step, the carbon, on the other hand, penetrates deep into the component due to the high diffusion coefficient. After quenching, a martensitic microstructure is thus produced in the majority of the component volume, as a result of which the sintered component becomes brittle and the fatigue properties are reduced.
    With subsequent turning or machining as well as during grinding operations, the material removal can be taken into account in an oversize of the surface layer, i. in the carburisation step, the edge layer is produced with a larger layer thickness corresponding to the oversize.
    In one embodiment variant of the method, it is also possible to combine the step of steam treatment or oxidation with a burn-off process, so that the additional method step, as stated above, can be dispensed with. At the same time, the temperature is regulated at least in two stages, the firing process being carried out in a first step with a temperature which is lower than that of the oxidation temperature, and it is then applied to this and / or N2012 / 16700. ············································· I
    • the temperature for the oxidation is increased to the values given above).
    Within the scope of the invention, the following tests, for example, which are listed by way of example in Table 1, have been carried out. It was to a gear made of a sintered powder. In order to be able to better verify the influences of the individual parameters described above, the same composition of the sintering powder was used for all experiments. It should be noted, however, that within the scope of the invention, other iron-based or iron-containing compositions may be used.
    Examples 1 to 3 were prepared by the process according to the invention. Example No. 4 was prepared by a prior art method. For the comparative experiment with a prior art sintered gear manufactured according to the same process route as the examples according to the invention, but without the steam treatment, the same composition of the powder was used,
    Composition of the sintering powder: 0.85% by weight Mo + 0.3% by weight C + 0.9% by weight pressing assistant, remainder Fe
    Pressing pressure for the production of the green body: 6 t / cm 2
    Temperature during sintering: 1250 ° C
    Sintering time: 45 minutes
    Composition of the reducing atmosphere: N2 / H2 (60% by volume / 40% by volume) 16/24 N2012 / 16700 16 ····································································· • · · · · · · · · · · · · · · · · · · · · · · ·
    Table 1 1 2 3 4 (comparative example) Oxidation time [minutes] 90 90 60 Oxidation temperature [° C] approx. 600 approx. 600 approx. 600 proportion of water vapor in the oxidation atmosphere [% by volume] 80 80 80 Belt speed [m / s ] 50 50 80 Oxide layer thickness [m] 4.1 4.1 3.5 T Oil [° C] 110 110 110 80 Carburizing time [minutes] 30 + 60 30 + 60 30 + 60 90 + 90 Carburizing temperature [° C] 830 860 860 900 Carbon level [%] 0,5 + 0,7 0,5 + 0,7 0,5 + 0,7 0,8 + 0,65 CTF0,50 [MPa] 658 898 862 7181 N2012 / 16700 1 : Heat treated and honed 17/24 17 • ·········································································
    The carburization was carried out at two different carbon levels. For this reason, two times are given in Table 1 for the carburization time, i. For example, Sample 1 was carburized for 30 minutes at a carbon level of 0.5% by volume and for 60 minutes at a carbon level of 0.7% by volume.
    The carbon level refers to the carbon content in the carburizing atmosphere.
    The oil temperature (T oil) in Table 1 indicates the temperature of the quench oil in which the sintered component is quenched.
    The composition of the atmosphere during carburizing has been chosen according to the state of the art.
    The finished sintered gears showed in comparative dynamic tests better fatigue properties than sintered gears of the same geometry, which were produced by a process without the formation of a diffusion barrier, in particular an oxide layer.
    Table 1 also shows from Sample No. 1 that lower fatigue strength is obtained at a lower carburizing temperature.
    It is possible with this method to produce sintered components in which the carbon content at the transition from the surface layer to the core zone decreases abruptly, in particular from 0.65% by weight to a value of less than 0.1% by weight, so that between the surface layer and the core zone a phase boundary that is clearly recognizable in the microsection is formed.
    In principle, carbon concentration gradients are adjustable which are between 0.8% by weight and less than 0.1% by weight, in particular between 0.7% by weight and 0.1% by weight.
    It is possible with the method according to the invention to produce sintered components which have a hardness HV 0.3 in the surface layer of between 600 and 750, in particular 18/24 N2012 / 16700 18 • · · · ♦ · · · · · ··· ♦ ······································································································ The hardness HV 0.3 in the core zone can be between 100 and 200, in particular between 120 and 180.
    In addition to gears of any kind, other sintered components can be produced by the method according to the invention, for example, synchronizer rings, sliding sleeves, coupling body, etc ..
    In the further method for producing the assembly, at least one of the sintered components thus produced and case-hardened is joined by welding with a further sintered component, which may also have been produced in the manner described above, or a component made of solid material of an iron-base material, in particular steel.
    The assembly may, for example, comprise or be formed from a gearwelded on a shaft or a welded (or welded) coupling body or a welded component of a synchronization device.
    The component of the solid material, so for example, the shaft may also be case hardened, as is known from the prior art. Thus, this component can also have a higher proportion of carbon in the edge region than in the core region.
    Before the components are connected to one another, that is to say the first sintered component with the second sintered component, it is of course also possible to connect more than two components to the assembly, all or some of which can be produced by the method described above-at least in the first sintered component removed with increased carbon content at least in the region of the joint. The removal takes place in particular by means of mechanical methods, for example by machining removal, as known from the prior art.
    Preferably, the layer having the increased carbon content is removed to a layer thickness at which the carbon content has decreased by at least 80%, based on the carbon content at the surface of the sintered component. 19/24 N2012 / 16700 19 • · · · · · · · · · ·············································································
    If more components are used, which have an outer edge layer with an increased carbon content, it is preferable for all of these parts, at least in the region of the joint, to remove this layer before welding.
    By "in the region of the joint" it is meant that the removed area may be slightly larger, for example by up to 5%, than the area of the actual joint area. However, this does not mean that this layer is removed on the entire component.
    Compared to the prior art is achieved with the inventive method that, for example, not a layer must be removed up to a layer thickness of 2 mm, but only up to a layer thickness of 0.5 mm maximum. 20/24 N2012 / 16700
    权利要求:
    Claims (5)
    [1]
    1. A method for producing an assembly of a first sintered component and a further sintered component or a component made of solid material, wherein the one or more sintered components are made of an iron-based sintered material, in particular steel, and the component of the solid material is made of an iron-based material, in particular steel, wherein further in the first and optionally second sintered component before joining together or with the component of the solid material, the carbon content is increased by carburizing, and wherein before joining at least in the first sintered component, a layer with increased carbon content is removed at least in the region of the joint, characterized in that prior to carburizing the carburized area, in particular the entire sintered component , at least partially with a diffusion barrier f is provided r the carbon.
    [2]
    2. The method according to claim 1, characterized in that the diffusion barrier is generated by oxidation of the material of the component.
    [3]
    3. The method according to claim 2, characterized in that the oxidation is carried out with steam.
    [4]
    4. The method according to any one of claims 2 to 3, characterized in that the oxidation is carried out at a temperature between 400 ° C and 800 ° C. 21/24 N2012 / 16700 2 • • • • • ·· • · • · · · · · · · · · · · ·
    [5]
    5. The method according to any one of claims 2 to 4, characterized in that the oxidation is combined with a Abbrennvorgang. Miba Sinter Austria GmbH

    Lawyers Burger &amp; Partner Attorney at Law 22/24 N2012 / 16700
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    同族专利:
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    FR2995615A1|2014-03-21|
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    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    JPS5789471A|1980-11-25|1982-06-03|Komatsu Ltd|Carburizing heat treatment for steel|
    DE3301541A1|1983-01-19|1984-07-19|Ringsdorff-Werke GmbH, 5300 Bonn|Process for the production from surface-hardened sintered bodies|
    DE102005012602B3|2005-03-18|2006-06-08|Aktiebolaget Skf|Method for bearing arrangement involves roller bearing ring that exhibits carrier element and the bearing rings are made either by mechanical cutting work or by providing air passage|
    DE102011109473A1|2011-08-04|2012-03-15|Daimler Ag|Sintered component e.g. cam for assembled camshaft of internal combustion engine, comprises surface portion of sintered component, boundary layer compaction, and hardened region, where compression layer is produced in surface portion|
    CN105618736A|2016-02-21|2016-06-01|刘辉|Reamer bit|
    DE102016122826A1|2016-11-25|2018-05-30|Schaeffler Technologies AG & Co. KG|The wave gear|
    法律状态:
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    ATA1026/2012A|AT513429B1|2012-09-20|2012-09-20|Method for producing a sintered component module|ATA1026/2012A| AT513429B1|2012-09-20|2012-09-20|Method for producing a sintered component module|
    FR1357540A| FR2995615A1|2012-09-20|2013-07-30|PROCESS FOR PREPARING A SET OF SINTERED ELEMENTS|
    DE201310109572| DE102013109572A1|2012-09-20|2013-09-03|Method for establishing sintered component module, involves increasing carbon content in sintered components and removing layer having increased carbon content and diffusion barrier between components before interconnecting components|
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