WO2013064698A2 - Procédé de fabrication d'éléments structuraux de résistance élevée en acier moulé présentant des propriétés trip/twip et utilisation des éléments structuraux ainsi réalisés - Google Patents

Procédé de fabrication d'éléments structuraux de résistance élevée en acier moulé présentant des propriétés trip/twip et utilisation des éléments structuraux ainsi réalisés Download PDF

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WO2013064698A2
WO2013064698A2 PCT/EP2012/071862 EP2012071862W WO2013064698A2 WO 2013064698 A2 WO2013064698 A2 WO 2013064698A2 EP 2012071862 W EP2012071862 W EP 2012071862W WO 2013064698 A2 WO2013064698 A2 WO 2013064698A2
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Prior art keywords
cold
austenitic
semi
finished
components
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PCT/EP2012/071862
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German (de)
English (en)
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WO2013064698A3 (fr
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Andreas Weiss
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Technische Universität Bergakademie Freiberg
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Priority to DE112012004621.8T priority Critical patent/DE112012004621A5/de
Publication of WO2013064698A2 publication Critical patent/WO2013064698A2/fr
Publication of WO2013064698A3 publication Critical patent/WO2013064698A3/fr

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    • 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
    • C21D6/00—Heat treatment of ferrous alloys
    • C21D6/004—Heat treatment of ferrous alloys containing Cr and Ni
    • 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
    • C21D6/00—Heat treatment of ferrous alloys
    • C21D6/005—Heat treatment of ferrous alloys containing Mn
    • 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
    • C21D7/00—Modifying the physical properties of iron or steel by deformation
    • C21D7/02—Modifying the physical properties of iron or steel by deformation by cold working
    • 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
    • C22C38/001—Ferrous alloys, e.g. steel alloys containing N
    • 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
    • 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
    • C22C38/58—Ferrous alloys, e.g. steel alloys containing chromium with nickel with more than 1.5% by weight of manganese
    • 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
    • C21D2211/001—Austenite
    • 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
    • C21D2211/008—Martensite
    • 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
    • C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
    • C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
    • C21D8/0221—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the working steps
    • C21D8/0236—Cold rolling
    • 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
    • C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
    • C21D8/10—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of tubular bodies
    • 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
    • C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
    • C21D9/08—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for tubular bodies or pipes
    • 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
    • C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
    • C21D9/36—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for balls; for rollers
    • 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
    • C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
    • C21D9/38—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for roll bodies
    • 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
    • C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
    • C21D9/40—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for rings; for bearing races

Definitions

  • the invention relates to a method for producing high-strength components made of cast steel with TRIP / TWIP properties.
  • the cast steel used has an austenitic or austenitic-martensitic structure. The process produces low-cost, high-strength, lean components, even with complicated geometry.
  • WO 2008/009722 A1 describes a process for the production of austenitic stainless steel castings and their use.
  • a cast steel is shown, which shows a TRIP effect due to its chemical composition.
  • the TRIP effect results in a simultaneous increase in strength and toughness. For example, tensile strengths of more than 550 MPa and elongations at break of more than 30% are achieved for the cast steel parts.
  • the steel moldings do not undergo hot or cold forming during the manufacturing process.
  • the TRIP effect is only triggered in the cast steel parts during use. For this purpose, external stresses must act on the material. Due to the TRIP effect, the steel cast solidifies and also has a large toughness reserve, which protects the steel from breakage.
  • the patent specification DE 102009013631 B3 describes a method for producing high-strength molded parts (components) in its final dimensions from high-alloy cast steel with plasticity effects and their use.
  • a near-net shape blank with narrow dimensional tolerance by casting preferably produced by the fine-pressure casting or squeeze casting process of high-alloy steel casting with TRIP or TWIP effect.
  • the geometry of the cast, near-net shape blank differs only slightly from the geometry of the finished part. Therefore, this blank undergoes only a small cold forming below 200 ° C.
  • the technology concept underlying DE 102009013631 B3 consists of the casting of a near-net shape blank, which receives the final contours of the finished part by a weak cold forming without or, if appropriate, with a recrystallization annealing.
  • a disadvantage of the described method is that only end sparklentahe castings are used as the starting material for the finished molded parts.
  • the dimensions and geometries of the near-net shape castings differ only slightly from the dimensions and geometries of the finished part.
  • the first cold working degree is less than 20% for austenitic steels and less than 15% for austenitic-martensitic steels.
  • an intermediate annealing must be carried out in order to realize further cold forming and to transfer the casting into the finished part. Due to the low cold forming, the strength-increasing effect of cold forming is weak.
  • the invention has for its object to develop a process for the production of high-strength steel castings with TRIP / TWIP properties, which allows to produce these components inexpensively by cold working of semi-finished in the form of, for example, heavy plate, tube, rod and coil material.
  • the object is achieved by a method for producing high-strength components in the form of high-cold-formed semi-finished or high-cold formed molded parts, in austenitic or austenitic-martensitic steel casting with
  • Cold forming means that the cast semifinished product or molded part cooled down to room temperature is not warmed up before or during the shaping, wherein heating by the deformation itself does not count as warming up. According to the invention, however, the cold-formed semi-finished products or molded parts are cooled during cold forming, ie heating of the castings is restricted during cooling by cooling or by stepwise cold forming with subsequent cooling to room temperature. With a correspondingly high re-use of cold-formed castings in the vicinity of room temperature, without recrystallization or reversion of the austenite austenite in austenite, extremely high flow rates can be achieved in this way. Elongation limits are generated. In the case of very high cold forming, the yield and flow limits are only slightly lower than the tensile strengths of the components.
  • the room temperature is determined by the ambient temperature of the air.
  • the temperature of the medium used (air, oil, water) to which the parts are subjected at the beginning of cold forming determines the initial temperature during forming. If the parts are removed, for example, from fresh tap water, this initial temperature is usually slightly lower than room temperature. However, in the sense of the inventive method, this temperature is likewise attributed to the room temperature for cold forming.
  • the degree of cold transformation ⁇ in% is the quotient of length or thickness change to initial length or thickness times 100%.
  • Martensit temperature or Ms temperature is the temperature at which 1% martensite spontaneously forms from austenite during cooling.
  • TRIP / TWIP property means that the austenite of the cast steel transforms into ⁇ - and / or ⁇ '-martensite during a mechanical stress deformation-induced. As a result, the plastic deformation capacity and the tensile strength increase. By twinning (TWIP effect) these property changes can be enhanced.
  • Austenitic steels are high-alloyed steels. At room temperature, they have an austenitic structure with u. U. small ⁇ -ferrite. The Ms temperatures for the ⁇ '- or ⁇ -martensite formations are below room temperature.
  • Austenitic-martensitic steels are also high-alloyed steels. They have a lower alloy content compared to austenitic steels. The Ms temperatures for the ⁇ '- or ⁇ -martensite formations are above room temperature.
  • Cast steel is steel, which is cast in molds.
  • stainless or high manganese austenitic or austenitic-martensitic steel casting with a chromium content of> 12% by mass or with a manganese content of> 16% by mass is used.
  • the carbon content of the used austenitic or austenitic-martensitic cast steel is less than 0.25 Ma%, the nitrogen content is less than 0.20 Ma%.
  • Austenitic and austenitic-martensitic steel castings with TRIP / TWIP properties endure extremely high cold work without any intermediate annealing and thus strengthen stronger than comparable steels without these effects.
  • Cold forming grades of more than 90% for the austenitic steels and more than 50% for the austenitic-martensitic steels near room temperature can be applied without any intermediate annealing.
  • a necessary condition is that heating of the castings during cold forming is restricted by cooling or by stepwise cold forming followed by cooling to room temperature.
  • the forming conditions (degrees of deformation, forming speed) must be adjusted so that the formed part does not exceed a temperature range of 60 to 80 ° C in the process of cold forming.
  • the cooling of the semifinished products or molded parts during cold forming is required so that their heating above 80 ° C is omitted.
  • the room temperature is raised to max. 60 ° C, preferably cooled to room temperature to 40 ° C. Heating above 80 ° C causes a weakening of the TRIP and TWIP effect of the cold formed part. This is associated with a decrease in the cold workability.
  • the cooling can be done by lubrication and consequent reduction of friction or by cooling media.
  • high cold working temperatures can be achieved without any intermediate annealing if a large number of passes are made with low stitch reductions and the parts are then cooled down to room temperature.
  • the cast semi-finished products or shaped parts have the shape of heavy plate, rod material, pipe or coil and are converted by the cold forming accordingly in sheet, in rod material with a smaller cross section, in thin-walled tube or in coil material.
  • cold forming takes place in several passes.
  • the molding or semi-finished product is cooled to room temperature after each cold forming pass.
  • the cold-formed semifinished product or molded part in the temperature range of 600 to 900 ° C, preferably in the temperature range of 600 to 800 ° C, annealing at a hold time of 5 to 30 min, preferably from 10 after 20 minutes and after cooling to room temperature subjected to further cold working with a degree of deformation of 20% to near 100% for austenitic steels and of more than 20% to 60% for austenitic-martensitic steels.
  • the remodeling martensite converts partially or completely into austenite without any recrystallization taking place. In this case, a reloading by cold forming at room temperature also high flow and expansion limits are achieved.
  • the annealing takes place at temperatures above the recrystallization temperature, the strength properties decrease and the toughness properties of the re-stressed components increase with increasing recrystallization or increasing retention time. If the recrystallization annealing achieves complete softening of the austenitic microstructure and, moreover, a finely dispersed austenite microstructure results, then in the case of renewed cold forming with appropriate cooling, a TRIP / TWIP effect can be triggered at a higher voltage level.
  • the annealed austenite exhibits a TRIP / TWIP effect at and above room temperature.
  • the strength properties of the recrystallized austenite are higher, the more finely disperse and higher the austenite is.
  • the measure of the product of tensile strength and elongation at break is high. This indicates a high cold workability of the recrystallized austenite in the intermediates.
  • the annealed products are subsequently subjected to further severe cold working, inducing a TRIP / TWIP effect at an elevated level of strength.
  • the formed material is cooled to room temperature.
  • the degrees of deformation are from 20 to close to 100% and for austenitic-martensitic steels from more than 20 to around 60%.
  • the result is finished, high-strength components made of high cold formed steel castings in the form of semi-finished or molded parts without and with complicated geometry that can be used as a construction, wear or crash element.
  • the cold-formed semi-finished products or molded parts hereinafter also referred to as components, components after the last cold forming step in the temperature range between room temperature and 100 ° C, preferably between room temperature and 80 ° C, 1 h to 72 hours, preferably 1 h to 48 hours, outsourced.
  • the semi-finished products or molded parts produced by the process according to the invention can be outsourced to increase the strength properties.
  • the aging takes place by holding at temperatures above room temperature and is particularly effective in cold-formed structural states.
  • the increases in strength increase with increasing degree of cold working, increasing aging temperature and removal time.
  • the toughness properties decrease with increasing cold working degree and increasing aging temperature and with increasing aging time.
  • Outsourced components have a yield strength of up to 150 MPa compared to non-paged components with a 0.2% proof strength.
  • the fatigue strength is up to 70 MPa higher.
  • the outsourcing effect is accompanied by up to a three-fold increase in the elongation at break compared to non-outsourced components.
  • the components produced according to the invention achieve a high property profile with respect to the combination of tensile strength and elongation at break compared to the parts which are produced via the near-net-cast route.
  • finished semi-finished products and molded parts according to the invention have high strength properties, high hardnesses and high wear resistance combined with low toughness properties. Comparable properties can not be achieved by hot forming or by near-net-shape casting technology.
  • By increasing the strength of manufactured structural parts can absorb higher forces, and it is possible to produce high-strength precast parts with slim dimensions and complicated geometries. Thus, the benefits of Leichbaus come into play.
  • the components produced by the method according to the invention with their properties can not be generated by the near net shape casting technology and a lower cold working of the castings.
  • the inventive method is material and energy saving and the manufactured components are used as a construction, wear or crash element with the highest quality.
  • finished austenitic cast steel components can have a 0.2% yield strength of about 400 to 950 MPa, a tensile strength of about 750 to 1200 MPa, a constriction of about 40 to 10% and an elongation at break of about 50 to 2% after aging at room temperature.
  • Finished components made of austenitic-martensitic cast steel are characterized by a 0.2% yield strength of about 450 to 1 100 MPa, a tensile strength of about 900 to 1600 MPa, a constriction of about 30 to 5% and an elongation at break of about 30 to 1% after aging at room temperature.
  • the mechanical parameters of the finished components are determined according to DIN 50 125 or DIN 50 1 14.
  • the hardness test is carried out according to Vickers.
  • the components are therefore suitable for high static and dynamic loads.
  • the components can be used for slim wear or crash elements, for mechanical and structural parts or as fastening and structural elements and for reinforcements.
  • the casting skin is removed. Thereafter, the board is thinned in a roll stand in several stitches by about 0.3 mm. As a result, the Board was thinned to a sheet with the thickness of 0.7 mm by rolling. The total cold working degree is thus 96%. There is no annealing between the individual stitches.
  • deformation twins and approximately 50% ⁇ '-martensite are formed in the cold-formed sheet.
  • the 0.2% yield strength of the sheet is 880 MPa and the tensile strength is 1040 MPa, the neck is 13% and the elongation at break is 5%.
  • the cast skin After pouring and solidifying, the cast skin is removed. Thereafter, the board is pre-rolled at room temperature to a thickness of 12 mm. This solidifies the material. Slip belts, stacking faults, twins and small amounts of ⁇ - and ⁇ '-martensite are formed in the austenite. As a result of ⁇ '-martensite formation, the cast steel becomes weakly ferromagnetic.
  • the cold formed board is subsequently subjected to annealing at 700 ° C and 20 minutes holding time and cooled in water to room temperature.
  • annealed austenite the structural defects produced by cold forming in the form of martensitic microstructure constituents are completely dissolved and no longer present.
  • the annealed austenite has above all a higher dislocation density and a smaller grain size than the austenite in the cast material. It is completely surprising that z. B. slip bands with twin structures in austenite after annealing partially retained. The is indicated indirectly by a hardness increase of about 20%.
  • the tensile strength of the annealed austenite has increased from the original 550 MPa to 650 MPa and the elongation at break from the original 60% to 71%. This indicates increased calcinability of the annealed austenite over the austenite in the as-cast condition.
  • the preformed blank with the annealed austenite is subsequently cold-rolled to 30 mm thickness at room temperature without intermediate heating and with lubricant to a thickness of 1 mm. After each pass, however, the sample heated by the cold working is cooled in water to room temperature before the next pass is made. The degree of cold working is 95%. Due to the very high cold forming, an austenitic-martensitic microstructure with ⁇ '-martensite content of approx. 25% has been established in addition to a large number of slip bands and deformation twins.
  • the finished sheet has a hardness HV 10 of 520, a 0.2% proof stress of 620 MPa, a tensile strength of 950 MPa and an elongation at break of 3 to 10%.
  • the chill casting produces a semi-finished product as a cast plate with a length of 500 mm, a width of 150 mm and a thickness of 15 mm. After casting and solidification, the casting skin is removed. Thereafter, the board is pre-rolled at room temperature to a thickness of 9 mm in several passes without intermediate heating. After each pass, however, the sample heated by the cold working is cooled in water to room temperature before the next pass is made.
  • This cold-formed board is subsequently subjected to an annealing at 700 ° C and 20 minutes holding time and cooled in water to room temperature.
  • the 30% formed martensite produced by the cold forming has been converted back into austenite.
  • the microstructure at room temperature again consists of approx. 50% austenite and approx. 50% ⁇ '-martensite.
  • the recrystallized and reverted austenite in turn has a significantly higher dislocation density and a smaller grain size than the austenite in the cast material. This is indirectly indicated by a hardness increase of almost 100%.
  • the tensile strength of the annealed austenitic-martensitic steel has increased by the treatment of originally 750 MPa to 950 MPa.
  • the elongation at break changes from originally 48% to 40%. This indicates increased cold workability of the annealed austenitic-martensitic steel over the cast condition.
  • the preformed board is then cold rolled in 10 passes at RT with no intermediate heating and with lubricant to a thickness of 7.5 mm. After each stitch, it is waited until the material has cooled down to room temperature. The total Endkaltumformgrad is thus about 50%. Due to the further cold forming an almost completely martensitic microstructure has set.
  • the heavy plate has a 0.2% proof stress of 860 MPa, a tensile strength of 1350 MPa and an elongation at break of 1.5%.
  • Shaped part made of austenitic CrMnNi steel
  • This tube is pressed together in a forming machine at room temperature, while about 30% cold formed. It is cooled down to room temperature with water or lubricant. The result is a solidified intermediate in the form of a round body.
  • This intermediate has a predominantly austenitic structure with a variety of structural defects and increased dislocation density.
  • This part subsequently undergoes annealing at 700 ° C and 20 minutes holding time. After water cooling, an austenitic state has been set at an increased level of strength with an improved TRI P / TW IP effect.
  • the recrystallized molded part is therefore subsequently finished in several cold forming steps with very high and different degrees of cold deformation of the pin and the ball in a rotary swaging machine to a ball joint pin. During the repeated cold forming with small forming steps is additionally cooled, so that the formed workpiece during kneading is kept approximately at room temperature.
  • the strongly formed parts of the pin and ball are high strength.
  • the structure of the ball, which is exposed to wear in use, is predominantly martensitic.
  • the hardness HV10 of the ball is 880 hardness units. Thus, the required resistance to the wear stress is applied.
  • the casting skin is removed. Thereafter, short proportional bars are made from the material.
  • the tensile bars are stretched at room temperature by 40% with a strain rate of 1 mm / s. Heating of the samples is thereby largely avoided.
  • a TRIP / TWIP effect is triggered. It forms sliding bands, stacking faults, twins and about 10% ⁇ '-deformation martensite.
  • the originally paramagnetic steel becomes ferromagnetic as a result of ⁇ '-martensite formation.
  • the 0.2% yield strength of the cast material is about 255 MPa and the strength after 40% elongation is 560 MPa, which corresponds to a true stress of 784 MPa.
  • the tensile bars stretched by 40% are subsequently removed at room temperature and at different times of 1 min and for 1, 3, 7 and 24 hours at room temperature and 80 ° C and subjected to breakage.
  • pre-stretched samples show an increase in the upper yield strength, tensile strength and elongation at break.
  • Tables 1 and 2 show the change in these properties as a function of the aging time at room temperature and 80 ° C.
  • the upper yield strength, the tensile strength and the elongation at break increase. Instead of the original 0.2% proof stress, an increasingly pronounced lower and upper yield strength is registered with increasing aging time.
  • the upper yield strength is close and only slightly below the tensile strength of the steel.
  • the proportion of ⁇ '-deformation martensite does not change due to reloading and paging. In all tensile specimens stretched by 40% at room temperature, the proportion is about 10%.
  • Table 1 Change in mechanical properties as a function of the aging time at room temperature.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Heat Treatment Of Steel (AREA)

Abstract

La présente invention concerne un procédé de fabrication d'éléments structuraux de résistance élevée en acier austénitique ou austénitique-martensitique coulés présentant des propriétés TRIP/TWIP et ayant une valeur équivalente pour l'énergie de défaut d'empilement de l'austénite W < 35mJ/m2 selon la relation appropriée. Selon l'invention, des produits semi-finis ou des pièces moulées sont tout d'abord fondus à partir d'acier moulé au moyen de procédés de fusion courants, et coulés sans être soumis à une tolérance dimensionnelle restreinte, les produits semi-finis ou les pièces moulées étant ensuite formés à froid avec un degré de déformation allant de 20 % jusqu'à près de 100 % pour des aciers austénitiques et allant de plus de 20% à 60% pour des aciers austénitiques-martensitiques. Au cours du formage à froid, les produits semi-finis ou les pièces moulées traités sont refroidis de sorte que leur échauffement reste inférieur à 80 °C. Les éléments structuraux ainsi fabriqués peuvent être employés comme éléments de construction, éléments d'usure ou éléments anti-choc.
PCT/EP2012/071862 2011-11-05 2012-11-05 Procédé de fabrication d'éléments structuraux de résistance élevée en acier moulé présentant des propriétés trip/twip et utilisation des éléments structuraux ainsi réalisés WO2013064698A2 (fr)

Priority Applications (1)

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DE112012004621.8T DE112012004621A5 (de) 2011-11-05 2012-11-05 Verfahren zur Herstellung hochfester Bauteile aus Stahlguss mit TRIP/TWIP Eigenschaften und Verwendung der hergestellten Bauteile

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DE102011117846.9 2011-11-05
DE102011117846 2011-11-05

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WO2013064698A2 true WO2013064698A2 (fr) 2013-05-10
WO2013064698A3 WO2013064698A3 (fr) 2014-05-01

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EP2749659A1 (fr) * 2012-12-07 2014-07-02 Benteler Automobiltechnik GmbH Procédé de fabrication d'un composant de véhicule automobile et composant de véhicule automobile
WO2016020519A1 (fr) * 2014-08-07 2016-02-11 Technische Universität Bergakademie Freiberg Produits semi-finis à haute résistance et en même temps durs, et composants en acier fortement allié, leur procédé de fabrication et utilisation
WO2016177473A1 (fr) * 2015-05-05 2016-11-10 Technische Universität Bergakademie Freiberg Procédé de production de tôles minces en acier crmnni inoxydable austénitique
DE102015210313A1 (de) 2015-06-03 2016-12-08 Technische Universität Bergakademie Freiberg Verfahren zur Herstellung dünnwandiger Stahlgussteile aus hoch legierten Stählen mit TRIP/TWIP-Eigenschaften
DE102016117494A1 (de) 2016-09-16 2018-03-22 Salzgitter Flachstahl Gmbh Verfahren zur Herstellung eines umgeformten Bauteils aus einem mittelmanganhaltigen Stahlflachprodukt und ein derartiges Bauteil
RU2692151C1 (ru) * 2017-12-28 2019-06-21 Федеральное государственное автономное образовательное учреждение высшего образования "Белгородский государственный национальный исследовательский университет" (НИУ "БелГУ") Способ получения листов высокопрочных аустенитных марганцовистых сталей

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CN112680660B (zh) * 2020-12-03 2022-04-15 山东钢铁集团日照有限公司 一种1.2GPa级TRIP钢及其微观组织的调控方法

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DE102009013631B3 (de) 2009-03-18 2010-08-19 Burkhard Weiss Verfahren zur prozessstufenarmen Herstellung hochfester, hochwertiger Formteile aus hochlegierten Stählen mit Plastizitätseffekt und deren Verwendung

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2749659A1 (fr) * 2012-12-07 2014-07-02 Benteler Automobiltechnik GmbH Procédé de fabrication d'un composant de véhicule automobile et composant de véhicule automobile
WO2016020519A1 (fr) * 2014-08-07 2016-02-11 Technische Universität Bergakademie Freiberg Produits semi-finis à haute résistance et en même temps durs, et composants en acier fortement allié, leur procédé de fabrication et utilisation
WO2016177473A1 (fr) * 2015-05-05 2016-11-10 Technische Universität Bergakademie Freiberg Procédé de production de tôles minces en acier crmnni inoxydable austénitique
DE102015210313A1 (de) 2015-06-03 2016-12-08 Technische Universität Bergakademie Freiberg Verfahren zur Herstellung dünnwandiger Stahlgussteile aus hoch legierten Stählen mit TRIP/TWIP-Eigenschaften
DE102015210313B4 (de) 2015-06-03 2018-09-27 Technische Universität Bergakademie Freiberg Verfahren zur Herstellung dünnwandiger Stahlgussteile aus hoch legierten Stählen mit TRIP/TWIP-Eigenschaften
DE102016117494A1 (de) 2016-09-16 2018-03-22 Salzgitter Flachstahl Gmbh Verfahren zur Herstellung eines umgeformten Bauteils aus einem mittelmanganhaltigen Stahlflachprodukt und ein derartiges Bauteil
WO2018050634A1 (fr) 2016-09-16 2018-03-22 Salzgitter Flachstahl Gmbh Procédé pour la fabrication d'une pièce façonnée à partir d'un produit plat en acier à teneur moyenne en manganèse et pièce correspondante
RU2692151C1 (ru) * 2017-12-28 2019-06-21 Федеральное государственное автономное образовательное учреждение высшего образования "Белгородский государственный национальный исследовательский университет" (НИУ "БелГУ") Способ получения листов высокопрочных аустенитных марганцовистых сталей

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