Classifications

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  • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
  • C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
  • C21D1/18—Hardening; Quenching with or without subsequent tempering
  • C21D1/19—Hardening; Quenching with or without subsequent tempering by interrupted quenching
  • C21D1/22—Martempering
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  • C22C—ALLOYS
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  • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
  • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
  • C22C38/46—Ferrous alloys, e.g. steel alloys containing chromium with nickel with vanadium
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  • C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
  • C21D1/18—Hardening; Quenching with or without subsequent tempering
  • C21D1/25—Hardening, combined with annealing between 300 degrees Celsius and 600 degrees Celsius, i.e. heat refining ("Vergüten")
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  • C21D6/00—Heat treatment of ferrous alloys
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  • C21D6/00—Heat treatment of ferrous alloys
  • C21D6/001—Heat treatment of ferrous alloys containing Ni
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  • C21D6/00—Heat treatment of ferrous alloys
  • C21D6/002—Heat treatment of ferrous alloys containing Cr
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  • C21D6/00—Heat treatment of ferrous alloys
  • C21D6/005—Heat treatment of ferrous alloys containing Mn
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  • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
  • C21D6/00—Heat treatment of ferrous alloys
  • C21D6/008—Heat treatment of ferrous alloys containing Si
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C38/00—Ferrous alloys, e.g. steel alloys
  • C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon
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  • C22C—ALLOYS
  • C22C38/00—Ferrous alloys, e.g. steel alloys
  • C22C38/04—Ferrous alloys, e.g. steel alloys containing manganese
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  • C22C—ALLOYS
  • C22C38/00—Ferrous alloys, e.g. steel alloys
  • C22C38/06—Ferrous alloys, e.g. steel alloys containing aluminium
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  • C22C—ALLOYS
  • C22C38/00—Ferrous alloys, e.g. steel alloys
  • C22C38/08—Ferrous alloys, e.g. steel alloys containing nickel
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  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C38/00—Ferrous alloys, e.g. steel alloys
  • C22C38/12—Ferrous alloys, e.g. steel alloys containing tungsten, tantalum, molybdenum, vanadium, or niobium
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  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
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  • C22C38/00—Ferrous alloys, e.g. steel alloys
  • C22C38/14—Ferrous alloys, e.g. steel alloys containing titanium or zirconium
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  • C22C—ALLOYS
  • C22C38/00—Ferrous alloys, e.g. steel alloys
  • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
  • C22C38/22—Ferrous alloys, e.g. steel alloys containing chromium with molybdenum or tungsten
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  • C22C—ALLOYS
  • C22C38/00—Ferrous alloys, e.g. steel alloys
  • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
  • C22C38/24—Ferrous alloys, e.g. steel alloys containing chromium with vanadium
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  • C22C—ALLOYS
  • C22C38/00—Ferrous alloys, e.g. steel alloys
  • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
  • C22C38/26—Ferrous alloys, e.g. steel alloys containing chromium with niobium or tantalum
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  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C38/00—Ferrous alloys, e.g. steel alloys
  • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
  • C22C38/28—Ferrous alloys, e.g. steel alloys containing chromium with titanium or zirconium
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C38/00—Ferrous alloys, e.g. steel alloys
  • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
  • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
  • C22C38/44—Ferrous alloys, e.g. steel alloys containing chromium with nickel with molybdenum or tungsten
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  • C21—METALLURGY OF IRON
  • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
  • C21D2211/00—Microstructure comprising significant phases
  • C21D2211/002—Bainite
• • C—CHEMISTRY; METALLURGY
  • C21—METALLURGY OF IRON
  • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
  • C21D2211/00—Microstructure comprising significant phases
  • C21D2211/004—Dispersions; Precipitations
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  • C21D2211/00—Microstructure comprising significant phases
  • C21D2211/008—Martensite
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  • C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
  • C21D9/18—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for knives, scythes, scissors, or like hand cutting tools
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  • C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
  • C21D9/22—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for drills; for milling cutters; for machine cutting tools

Definitions

• the present invention relates to a tool steel with very high thermal diffusivity and high wear resistance, mainly abrasive. This tool steel also shows good hardenability.
• Wear in material shaping processes is, primarily, abrasive and adhesive, although sometimes other wear mechanisms, like erosive and cavitative, are also present.
• hard particles are generally required in tool steels, these are normally ceramic particles like carbides, nitrides, borides or some combination of them.
• the volumetric fraction, hardness and morphology of the named hard particles will determine the material wear resistance for a given application.
• the use hardness of the tool material is of great importance to determine the material durability under abrasive wear conditions.
• the hard particles morphology determines their adherence to the matrix and the size of the abrasive exogenous particle that can be counteracted without detaching itself from the tool material matrix.
• FGM materials functionally graded materials
• the tool material must be hard and have hard particles.
• Thermal gradients are the cause of thermal shock and thermal fatigue. In many applications steady transmission states are not achieve due to low exposure times or limited amounts of energy from the source that causes a temperature gradient.
• the magnitude of thermal gradient for tool materials is also a function of their thermal conductivity (inverse proportionality applies to all cases with a sufficiently small Biot number).
• a material with a superior thermal conductivity is subject to a lower surface loading, since the resultant thermal gradient is lower.
• the thermal expansion coefficient is lower and the Young's modulus is lower.
• the invention is related to a process to manufacture a hot work tool steel, characterised in that the steel is subjected to a martensitic, bainitic or martensitic- bainitic quench with at least one tempering cycle at temperature above 590°C, so that a steel having a hardness above 47 HRc with a low scattering structure characterized by a diffusivity of 9 mm 2 /s or more is obtainable.
• a steel having a hardness above 53 HRc with a low scattering structure characterized by a diffusivity of 9 mm 2 /s or more is obtainable.
• the steel is subjected to at least one tempering cycle at temperature above 660°C, so that a steel having a hardness of 50 HRc or more with a low scattering structure characterized by a diffusivity of 5.8mm 2 /s or more at 600 °C is obtainable.
• Tool steels of the present invention have a thermal diffusivity above 8 mm 2 /s and, often, above 12 mm 2 /s for hardness over 52 HRc, and even more than 16 mm 2 /s for hardness over 42 HRc, furthermore presenting a very good wear resistance and good hardenability.
• Thermal diffusivity is considered the most relevant thermal property since it is easier to measure accurately and because most of the tools are used in cyclic processes, so that the thermal diffusivity is much more important for evaluating performance of the tool than can be thermal conductivity.
• Tool steels of the present invention have a wear resistance and hardness higher than steels described in EP2236639A1.
• the tool steels of the present invention can attain much higher levels of thermal diffusivity than the tool steels of WO2004/046407 Al, where the high levels of %Cr impose very tight restrictions which are not observed, on the compositions to be taken within the proposed range and the small process window thereafter during the thermo-mechanical processing to attain high levels of carrier mobility.
• %Cr has the tendency to dissolve in the W and/or Mo carbides causing the dispersion of the heat energy carriers and thus their presence is also undesirable. This is the only point of coincidence that also, in the case of JP04147706, does not lead to high thermal diffusivity in any of the examples described. At an even lower extent is the case of JP11222650, where the inventors look for the presence of large amounts of primary carbides to resist massive wear as is the case for high speed steel but with an exceptionally low content of %C to allow cold coining.
• %Cr does not compel the use of especial scraps and, if there are not other elements that require so, then a %Cr > 0.5 can be expected. Even more important is the placement of this %Cr, which will be predominantly dissolved in the carbides if no special measures are taken.
• %Si is slightly different, since it is possible to reduce its content through a refining process, such as ESR, although, due to the narrow window of the process in this case, it is technologically very difficult (and expensive, and therefore it is only carried out in the case of seeking a specific functionality) to reduce the %Si below 0.2 and, at the same time, to reach a low level of inclusions (especially oxides).
• a refining process such as ESR
• thermo-mechanical treatments used do not pursue the maximization of mobility of the heat energy carriers.
• Thermal conductivity is not properly chosen as one of the main desirable characteristic or, for materials previously developed, the knowledge was lacking on how to attain a desired level of thermal diffusivity before the publication of EP 1887096 Al, and thus the phases present in the final microstructure are chosen according to the optimization of some other properties desirable for the application, generally a certain compromise of relevant, to the application, mechanical properties.
• strengthening mechanisms are chosen which are very detrimental for thermal diffusivity.
• the nominal levels of certain critical elements are far away from the real content values in the embodiment. For instance, this is often the case for %Si and %Cr. While the nominal composition can describe a certain level, especially in the case of only upper bound descriptions, like %Cr ⁇ 1 (or even without mentioning the %Cr, which can lead to the erroneous assumption that is 0%) and in the same fashion as often the case %Si ⁇ 0.4, it ends up by being %Cr > 0.3 and %Si > 0.25. This applies also for all trace elements with a strong influence on the conductivity of the matrix and even more those with a high solubility in carbides and great potential for distortion of the carbides structure.
• thermo-mechanical treatments to be used, some of which are described below, have to be taken into account.
• Thermal diffusivity is a consequence of the scattering mechanisms on the phases present for all carrier types present. The perfection of the lattice plays an important role, but also other scattering mechanisms are of relevance.
• the thermal diffusivity itself will be used as a measurement of the structure attained. Within a same chemical composition different structures can be attained and thus also different levels of thermal diffusivity.
• Tool steels of the present invention excel mainly because of their high thermal diffusivity and wear resistance. Wear resistance and toughness tend to be inversely proportional, although different microstructures reach different relationships, i.e., as a function of microstructure different levels of toughness for the same elastic limit and hardness at a given temperature can be reached and, for a specific type of material, hardness tends to correlate with wear resistance unless the volume fracture or the morphology of wear resistant particles is significantly changed. In this vein, it is well known that for most tool steels with medium carbon content, pure microstructure of tempered martensite is the only one that offers the best compromise of mechanical properties.
• a strategy to obtain wear resistance and higher elastic limit at high temperatures and, at the same time, obtain high thermal conductivity is the use of carbides with high electron density, as secondary carbides of the M 3 Fe 3 C type and sometimes even primary carbides (M- should only be Mo or W for a greater thermal conductivity).
• carbides with high electron density As secondary carbides of the M 3 Fe 3 C type and sometimes even primary carbides (M- should only be Mo or W for a greater thermal conductivity).
• M- should only be Mo or W for a greater thermal conductivity There are other carbide types (Mo, W, Fe) with high electron densities and with tendency to solidify with a good crystalline perfection.
• these high carbide forming elements tend to form separate MC type carbides, due to its high affinity for
• this combination is highly desirable as the percentage of V as the percentage of Zr, Hf and Ta tend to significantly improve the wear resistance compared to a steel that has only carbides (Fe, Mo, W), the same applied for %Nb.
• %Ceq is smaller than 0.35 then %V should be kept below 1.7%.
• Fe, Mo and W carbides where obviously part of the C can be replaced by N or B, usually more that 60% and, optimally, more than 80% or even more than 90% of these type of carbides.
• %Cr is commonly used, but has an extremely negative effect on the thermal conductivity for this system because it dissolves in the M 3 Fe 3 C carbides and causes a great distortion, so it's much better to use strong carbide forming elements and non soluble elements in carbides. These last elements will reduce the conductivity of the matrix and, thus, the ones with the minimum negative effect should be used. Accordingly, the natural candidate is Ni, but at the same time others can be used (a special mention should be made to %B, for its effect with very low concentrations).
• carbide formers with great affinity to C are tend to be used for their positive effect on wear resistance, the necessary and desirable quantity of delaying elements of the transformation kinetics to stable structures during quenching is lower.
• a quantity up to 1% in weight, and for large sections up to 3.0% will be enough to get sufficient hardenability and contribute to the increase of toughness without an excessive detriment of conductivity.
• Higher %Ni quantities provide more toughness and a reduction in the linear thermal expanded coefficient, but the priority of the present invention is a combination of wear resistance with thermal diffusivity, thus, only for some special applications the strategy of using high contents of %Ni, with a maximum of 3.8%, can be used.
• %Mo, %W and %C used to obtain the desired mechanical properties must be balanced to achieve a high thermal conductivity, so that within the matrix remain the least amount of these elements in solid solution.
• carbide formers that could be used to obtain a certain tribological response (like %V, %Zr, %Hf, %Ta,).
• %Cr or %Si in solid solution (oxidation resistance to high temperature).
• the negative effect on thermal diffusivity can be moderated through carbon fixing with stronger carbide formers elements.
• %Cr should not exceed 2% and, preferable, 1.5%.
• V, %Nb, %Ta, %Zr and %Hf, and preferably the last two or three levels close to 3% of Cr can be achieved maintaining a good thermal diffusivity, and even 1.4% for the case of Si. In fact for most applications %Cr ⁇ 2.8%) is required if the thermal diffusivity needs to be high.
• compositions require %>Cr ⁇ 2.5 %> to be able to attain high thermal diffusivity with the proper thermo- mechanical processing (which is composition dependent, as explained). At this level the environmental protection effect is only somewhat noticeable if the %>Cr is mainly left in solid solution in the matrix. Finally, a much greater range of compositions can attain high thermal diffusivity when the proper thermo-mechanical treatment is applied, if %>Cr is restricted to remain below 1.9%.
• This rule applies only for big enough contents of %>C eq (normally 0.32 min, preferably 0.35 min and most accurately when 0.38 minimum %Ceq) and %Mo eq (normally 3.2 min, preferably 3.4 min and most accurately when 3.6 minimum %Moeq).
• the maximum value for R has been observed to be possibly 11.5, preferably 10.8 and optimally 10.5 for low %>C eq values.
• Low %>Ceq values are for this rule those under 0.35%), occasionally under 0.36%> or even under 0.37%.
• the maximum value for R has been observed to be possibly 16.8, preferably 16.0 and optimally 15. High %>C eq values are for this rule those above 0.38%>, occasionally above 0.40% or even above 0.45%. For intermediate values of %>C eq , the maximum value for R has been observed to be 14, preferably 13, and optimally 12.
• solV - vanadium percentage in solid solution solV - vanadium percentage in solid solution.
• R - number of carbide former units per carbide unit for example: 1 if the carbide type is MC, 23/7 if the carbide type would be M 23 C 7 ).
• AM - carbide former atomic mass for example: 1 if the carbide type is MC, 23/7 if the carbide type would be M 23 C 7 .
• This balance provides an extraordinary thermal conductivity if the reinforcing ceramic particles formers, including the non metallic part (%C, %B and %N), are taken into the carbides (as an alternative nitrides, borides and intermediate substances). Then, the appropriated thermal treatment must be applied. This thermal treatment will have a phase in which most of the elements will be dissolved (austenitization to sufficiently high temperature, usually around 1080°C for moderated Mo eq levels, 1120°C for medium levels of Mo e q and 1240°C for high levels of Mo eq , exceptionaly, if distortion of the heat treatment is of great importance for the application, lower austenitization temperatures can be used).
• the highest possible temperature is desirable for the last tempering if thermal diffusivity is to be maximized, and this approach is used to set the intermediate tempering strategy. That is, the same final hardness level can be achieved with different sequences of tempering and the one using a higher final tempering temperature is chosen, if the only objective is to maximize the thermal diffusivity at a certain level of hardness. So, usually, unusually high final tempering temperatures end up being used, often above 600°C, even when hardness over 50 HRc are chosen.
• steels of the present invention it is usual to achieve hardness of 47 HRc, even more than 52 HRc, and often more than 53 HRc and with the embodiments regarded as particularly advantageous due to their wear resistance, hardness above 54HRc, and often more than 56 HRc are possible with even one tempering cycle above 590°C, giving a low scattering structure characterized by a thermal diffusivity greater than 8 mm 2 /s and, generally, more than 9 mm 2 /s, or even more than 10 mm 2 /s, when particularly well executed then greater than 11 mm 2 /s, even greater than 12 mm 2 /s an occasionally above 12,5 mm 2 /s.
• the volume fraction of hard particles (carbides, nitrides, borides and mixtures thereof) is often above a 4% preferably above a 5.5% and for some high wear applications, even above a 9%.
• Size of primary hard particles is very important to have an effective wear resistance and yet not excessively small toughness. The inventors have observed that for a given volume fraction of hard particles overall resilience of the material diminishes as the size of the hard particles increases, as would be expected. A bit more surprisingly it has also been observed that when the size of hard particles is increased, the overall fracture toughness increases if the fracture toughness of the particles themselves is maintained.
• a critical hard particle size below which the hard particle is not effective against the abrasive agent.
• This critical size depends on the size of the abrasive agent and the normal pressure.
• the abrasive particles are of small size (normally below 20 microns)
• big primary hard particles will be desirable. Therefore, for some applications it is desirable to have some primary hard particles bigger than 12 microns, often greater than 20 microns and for some particular applications even greater than 42 microns.
• Small secondary hard particles are those with a maximum equivalent diameter (diameter of a circle with equivalent surface as the cross section with maximum surface on the hard particle) below 7.5 nm. It is then desirable to have a volume fraction of small secondary hard particles for such applications above 0.5%. It is believed that a saturation of mechanical properties for hot work applications occurs at around 0.6%, but ithas been observed by the inventors that for some applications requiring high plastic deformation resistance at somewhat lower temperatures it is advantageous to have higher amounts than these 0.6%, often more than 0.8% and even more than 0.94%.
• Heat treatment has to be selected with a rather high austenitization temperature and an abnormally high tempering temperaures, actually more than 55 HRc commonly achieved with at least one tempering cycle at 630 °C or even above, 50 HRc can be maintained even with one tempering cycle at 660 °C or more.
• Proper thermo-mechanical processing together with the compositional rules just explained have to be implemented to minimize scattering at high temperatures, the optimized arrangements is characterized by providing diffusivities of more than 5.8 mm2/s, often more than 6.1mm2/s and even more than 6.5mm2/s at measuring temperatures as high as 600 °C.
• MOeq(real) % ⁇ + 0.52*%W.
• Nb can be quite detrimental for the thermal diffusivity for some applications it will not be desirable (%Nb ⁇ 0.09) and then the contents of Hf, Zr and Ta in the sum should exceed 0.01%, preferably 0.07%) and in applications requiring high wear resistance with very high thermal diffusivity and where Zr is chosen as the main former of hard carbides, then contents above 0.14%>, preferably above 0.2%> and even above 0.4%>, will be desirable.
• the restrictions on K can be relaxed around a 3% to 5% for alloys with low carbon content as hereby described.
• the parameter K should exceed 0.6, preferably 0.75, more preferably 0.84 and optimally 0.87.
• the restrictions on K can be relaxed very severely, for some applications even eliminated.
• Another hardening mechanism can be used in order to search for some specific combination of mechanical properties or environmental degradation resistance. It is always the intention to maximize the desired property, but trying to have minimal possible adverse impact on thermal conductivity.
• Solid solution with Cu, Mn, Ni, Co, Si, etc... including some carbide formers with less affinity to carbon, like Cr) and interstitial solid solution (mainly with C, N and B).
• precipitation can also be used, with an intermetallic formation like Ni 3 Mo, NiAl, Ni 3 Ti... (also of Ni and Mo, small quantities of Al and Ti can be added, but special care must be taken for Ti, since it dissolves in M 3 Fe 3 C carbides and a 2% should be used as a maximum).
• atomic mass and the formed type of carbide determine if the quantity of a used element should be big or small. So, for instance, 2%V is much more than 4%W. V tends to form MC carbides, unless it dissolves in other existing carbides. Thus, to form a carbide unit only a unit of V is needed, and the atomic mass is 50.9415. W tends to form M 3 Fe 3 C carbides in hot work steels. So three units of W are needed to form a carbide unit, and the atomic mass is 183.85. Therefore, 5.4 more times carbide units can be formed with 2%V than with 4%W.
• Tool steel of the present invention can be manufactured with any metallurgical process, among which the most common are sand casting, lost wax casting, continuous casting, melting in electric furnace, vacuum induction melting. Powder metallurgy processes can also be used along with any type of atomization and eventually subsequent compacting as the HIP, CIP, cold or hot pressing, sintering (with or without a liquid phase and regardless of the way the sintering process takes place, whether simultaneously in the whole material, layer by layer or localized), laser cusing, spray forming, thermal spray or heat coating, cold spray to name a few of them.
• the alloy can be directly obtained with the desired shape or can be improved by other metallurgical processes.
• Tool steel of the present invention can be obtained in the form of bar, wire or powder (amongst others to be used as solder or welding alloy). Even, a low-cost alloy steel matrix can be manufactured and applying steel of the present invention in critical parts of the matrix by welding rod or wire made from steel of the present invention. Also laser, plasma or electron beam welding can be conducted using powder or wire made of steel of the present invention.
• the steel of the present invention could also be used with a thermal spraying technique to apply in parts of the surface of another material.
• the steel of the present invention can be used as part of a composite material, for example when embedded as a separate phase, or obtained as one of the phases in a multiphase material. Also when used as a matrix in which other phases or particles are embedded whatever the method of conducting the mixture (for instance, mechanical mixing, attrition, projection with two or more hoppers of different materials).
• Tool steel of the present invention can also be used for the manufacturing of parts under high thermo-mechanical loads and wear resistance or, basically, of any part susceptible to failure due to wear and thermal fatigue, or with requirements for high wear resistance and which takes advantage of its high thermal conductivity. The advantage is a faster heat transport or a reduced working temperature.
• components for combustion engines such as rings of the engine block
• reactors also in the chemical industry
• heat exchange devices generators or, in general, any power processing machine.
• Dies for forging open or closed die
• extrusion rolling, casting and metal thixoforming.
• any matrix, tool or part can benefit from increased wear resistance and thermal fatigue.
• dies, tools or parts that benefit from better thermal management as is the case of material forming or cutting dies with release of large amounts of energy (such as stainless steel or TRIP steels) or working at high temperatures (hot cutting, hot forming of sheet).
• Example 1 Some examples indicate the way in which the steel composition of the invention can be specified with higher precision for different hot working applications: Example 1
• V 0 - 0.9% (preferably 0.3 - 0.8%)
• Si ⁇ 0.15%
• Mn ⁇ 0.5%
• Mo eq 3.5 - 5.5
• compositional range can be used:
• V 0 - 2.0% (preferably 0.4 - 0.8%)
• compositional range of the following type can be used:
• compositional range of the following type can be used:
• Si ⁇ 0.15% (preferably Si ⁇ 0.1%)
• V 0 - 2% for cases with Mo eq > 5 and V: 0 - 4% for cases with Mo eq ⁇ 5

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• 2011
  • 2011-01-13 EP EP11382004A patent/EP2476772A1/fr not_active Withdrawn
• 2012
  • 2012-01-13 CA CA2824238A patent/CA2824238A1/fr not_active Abandoned
  • 2012-01-13 US US13/978,782 patent/US20140000770A1/en not_active Abandoned
  • 2012-01-13 EP EP12700396.0A patent/EP2663664A1/fr not_active Withdrawn
  • 2012-01-13 WO PCT/EP2012/050531 patent/WO2012095532A1/fr active Application Filing
  • 2012-01-13 MX MX2013008138A patent/MX2013008138A/es unknown
  • 2012-01-13 JP JP2013548855A patent/JP2014508218A/ja active Pending
  • 2012-01-13 EP EP17166724.9A patent/EP3330401A1/fr not_active Withdrawn
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