EP3209806A1 - Acier traité thermomécaniquement à très haute résistance - Google Patents

Acier traité thermomécaniquement à très haute résistance

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Publication number
EP3209806A1
EP3209806A1 EP15808458.2A EP15808458A EP3209806A1 EP 3209806 A1 EP3209806 A1 EP 3209806A1 EP 15808458 A EP15808458 A EP 15808458A EP 3209806 A1 EP3209806 A1 EP 3209806A1
Authority
EP
European Patent Office
Prior art keywords
steel
proportion
ultra
hot
high strength
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
EP15808458.2A
Other languages
German (de)
English (en)
Other versions
EP3209806B1 (fr
Inventor
Babasaheb Neelkanth Kalyani
Madan Umakant TAKALE
Prakasam Balachandran DR. GNANA
Rajkumar Prasad DR. SINGH
Abhay Ramchandra CHAUTHAI
Suresh Babu ARANGI
Rajesh Surendra MANE
Kumar DHARMESH
Srinivas Perla
Vinayak Pralhad PAWAR
Shital Shahaji JADHAV
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Saarloha Advanced Materials Private Ltd
Bharat Forge Ltd
Original Assignee
Bharat Forge Ltd
Kalyani Carpenter Special Steels Pvt Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Bharat Forge Ltd, Kalyani Carpenter Special Steels Pvt Ltd filed Critical Bharat Forge Ltd
Publication of EP3209806A1 publication Critical patent/EP3209806A1/fr
Application granted granted Critical
Publication of EP3209806B1 publication Critical patent/EP3209806B1/fr
Active legal-status Critical Current
Anticipated expiration legal-status Critical

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Classifications

    • 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
    • C22C38/28—Ferrous alloys, e.g. steel alloys containing chromium with titanium or zirconium
    • 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
    • C21D8/0205—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips of ferrous alloys
    • 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
    • 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
    • C22C38/04—Ferrous alloys, e.g. steel alloys containing manganese
    • 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
    • C22C38/22—Ferrous alloys, e.g. steel alloys containing chromium with molybdenum or tungsten
    • 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
    • C22C38/26—Ferrous alloys, e.g. steel alloys containing chromium with niobium or tantalum
    • 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
    • C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
    • C21D1/26—Methods of annealing
    • C21D1/30—Stress-relieving
    • 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
    • C21D2211/002—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
    • C21D7/00—Modifying the physical properties of iron or steel by deformation
    • C21D7/13—Modifying the physical properties of iron or steel by deformation by hot working
    • 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
    • C21D8/0226—Hot 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
    • C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
    • C21D8/0247—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the heat treatment
    • C21D8/0263—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the heat treatment following hot rolling

Definitions

  • the present invention relates to ultra-high strength steel for structural components.
  • it relates to the process of making such steel that has a desirable microstructure in the thermo-mechanically processed and differently cooled conditions that delivers high fatigue resistance in service.
  • the steel and the process of its manufacturing technique enables manufacture of components that exhibit bainitic microstructure that impart ultra-high strength ranges with very high fatigue resistance properties.
  • the steel and its method of manufacturing process enables saving in alloying additives compared to hardened and tempered alloy steels and in addition avoid expensive heat treatment operations to achieve the desired range of mechanical properties.
  • the steel developed in the present invention is a suitable replacement for microalloyed steel bars used for structural component development.
  • the steel can be used for applied as the hot rolled and air cooled long products that can be directly used for applications or it can be directly hot forged in open or closed die forging followed by controlled cooling to achieve the desired microstructure and range of mechanical properties.
  • the ultra-high strength steel (UTS in the 1100 to 1420 MPa range) of the invention provides a competitive replacement for quench tempered alloy steels in terms of strength and fatigue, ductility, although its toughness is lower compared to Quenched and Tempered steels but superior to micro alloyed steels.
  • the potential steel bar product can be applied in various industries that include automotive, railways, general engineering, agricultural implements, construction, mining shafts, etc.
  • the steel exhibits unique range of mechanical properties that develops due to the process of invention which involves the steel chemistry and the thermo-mechanical processing followed by controlled cooling.
  • the present invention relates to innovative composition of a steel and associated thermo-mechanical processing of making it, such that it has desirable microstructure that gives ultra-high strength and fatigue resistance.
  • the fatigue properties of the steel rolled bar of the invention have been found to exhibit greater than 5 million cycles with rotating bending type testing at a stress level of 515MPa. It was also found that the fatigue life of the forged component of the invention is at least five times more than that of the existing alloy steel materials.
  • the present invention describes the steel composition and the entire process of making the steel from melting to thermo-mechanical processing to achieve steel with ultra-high strength and very high fatigue performance.
  • the ultra-high strength steel of the invention has Carbon in the range of 0.1 to 0.25% which provides the desired microstructure and the type of nano-carbides. It has Manganese (Mn) content between 1.2 and 2.5% and Chromium (Cr) content between 0.8 and 1.4% which helps the steel achieves the desired bainitic bay in the CCT diagram and the elements increase the hardenability. It also has Silicon (Si) level of 0.5 to 1.7% to achieve the desired microstructure in control cooled conditions. To improve the prior austenite grain structure, the steel is alloyed with 0.05 to 0.1% Niobium (Nb) content.
  • the effect of dynamic strain aging associated with Nitrogen is prevented by addition of 0.01 to 0.03% Titanium (Ti).
  • Molybdenum (Mo) to a level between 0.05 to 0.1% is added to the steel to promote and stabilise the bainitic microstructure. Boron to a level of 30 ppm was added to ensure hardenability over thicker cross sections.
  • the steel is aluminium killed with a residual Aluminium (Al) level ⁇ 0.02%.
  • the steel can have residual elements Nickel (Ni) in an amount up to 0.4% and Vanadium (V) up to 0.1%, sulphur (S) content ⁇ 0.03% and phosphorus (P) content ⁇ 0.02%.
  • the steel of the invention can be manufactured through electric induction or electric arc furnace or basic oxygen furnace route followed by alloying in a ladle or induction furnace.
  • the steel may be processed by ingot casting or continuous casting route, while the latter is preferred to achieve for higher yield and productivity.
  • the cast ingot or continuous cast blooms are hot worked at a temperature range of 1250° to 900°C in a forge press or in a hot rolling mill or hot extrusion or other related to semi or finished products.
  • the finishing temperatures are maintained in the range up to 1000 to 900°C.
  • as-hot worked steel is allowed to cool in air, or quenched in oil, water or polymer.
  • the water quenched sample may have up to 7% martensite depending on section thickness.
  • a stress relief tempering heat treatment at about 200 to 340°C is optionally employed.
  • the object of the present Invention is to develop an ultra- high strength steel with high fatigue resistance with thermo-mechanically processed and control cooled steel that is processed with induction or electric arc furnace or Basic oxygen furnace routes followed by secondary refining, vacuum degassing and traditional casting processes such as ingot casting or continuous casting.
  • Another object of the present investigation is to achieve a wide range of mechanical properties within Ultra high strength range by changing the cooling rate post thermo-mechanical processing in air, water, polymer, oil and vermiculite cooling.
  • Another object of the present invention is to propose usefulness of steel in weight reduction by atleast 10% as a substitute for heat treated alloy steels or microalloyed steels.
  • Another object of the invention is to minimize the cost of steel manufacturing as compared to alloy steels and savings associated with avoidance of heat treatment in alloy steels.
  • Another object of present invention is to produce ultra-high strength components having fatigue resistance of at least five times compared to regular heat treated or micro alloyed steels.
  • Figure 1 Manufacturing method process flow of ultra-high strength steel.
  • FIG. 1 Micro structure of the steel made at various cooling conditions showing the bainitic microstructure obtained at various processing conditions
  • FIG. 3 Automotive front axle beam manufactured using ultra-high strength steel grade.
  • Figure 4 Microstructure of the forging with invented ultra-high strength steel.
  • the present invention describes the development of ultra-high strength steel for potential use in light weighting and fatigue resistant component applications.
  • the primary steel is manufactured using induction furnaces, electric arc furnaces (EAF), ladle furnaces or basic oxygen furnaces.
  • the primary steel is suitably alloyed in a secondary refining furnace followed by vacuum degassing to produce the steel of designed chemistry additives shown in Table 1, based on theoretical considerations on alloy design principles.
  • the steel is refined and killed with Aluminium (Al) to get a residual oxygen level to less than 15ppm. This is found to reduce the potential oxide inclusions that have an effect on the fatigue life of the component that may be made using the steel of the present invention.
  • Table 1 Composition of the steel designed for meeting Ultra high strength ran e and fati ue resistance. Com osition in % w/w
  • the steel is cast through ingot casting preferably with bottom pouring up-hill casting technique or it may be cast as a concast steel product of suitable size.
  • the as-cast ingot or the concast bloom may be hot charged or cold charged in a furnace for further deformation.
  • the initial soaking for hot deformation is done at a temperature between 1280° C and 1220° C.
  • the soaked bloom is subject to hot forging or hot rolling. Suitable reduction per pass is applied.
  • the material gets deformed easily by forging or directly hot rolling with good surface finish.
  • the hot worked material may be suitably hot finished at a temperature between 1000 and 900° C. This is followed by control cooling the deformed steel in any of the cooling medium vermiculite, air, oil, polymer or water.
  • the distortion of the steel is depending on the quenching severity of the media.
  • the steel quenched in water or polymer may require a stress relief temper treatment at a temperature between 200 and 340 °C.
  • the invention discloses development of the steel and its processing where the content, morphology and distribution of the phases ensure the unique range of mechanical properties.
  • the bainitic transformation involves a displacive transformation followed by diffusion of carbon to form carbides that create the bainitic microstructures.
  • the invention discloses the stability of predominantly bainitic microstructure when control cooled in various media such as vermiculite, air, oil, polymer and water quenching which resulted in higher strength.
  • the invention also discloses development of steel which can be made at par with that of processing an air cooled micro alloyed steel but delivers ultra-high strength level and superior fatigue resistance.
  • the primary steel was melted in a 35MT electric arc furnace followed by secondary steel making using a ladle furnace.
  • the entire process flow followed is shown in Figure 1.
  • the process of the present invention ensures that the steel developed by adopting above mentioned process has Oxygen content less than 15ppm (a condition that is necessary to give ultra-high strength).
  • Secondary steel making followed by vacuum degassing ensures low gas content.
  • One advantage of completely air cooled bainitic structure is that the transformation has a natural tendency to reject hydrogen gas and the steel would be virtually free from hydrogen flaking unlike that in an alloy steel.
  • the steel in the present case was manufactured by continuous casting while ingot casting is also possible. Macro segregation was minimised by having low carbon and sulphur contents.
  • the steel can be hot or cold charged during deformation.
  • the as- cast steel is amenable for hot deformation using hot forging and hot rolling and in this specific case it was directly hot rolled with a reduction ratio more than 4 with a cross section of round corner square.
  • the hot deformation temperature at which thermo-mechanical processing is carried out is between 1280 and 850 °C.
  • the plastic deformation of the steel happens with good plastic flow behaviour and with no surface defects.
  • the finish rolling temperature was maintained in a range between 1000 to 900°C.
  • the steel after thermo-mechanical processing was subject to initially three different cooling rates using vermiculite cooling, air cooling or water quenching. Each of the three cooling methods leads to the formation of predominantly bainitic microstructure.
  • the typical mechanical properties achieved in the 35 MT directly hot rolled steel are shown in Table 3.
  • the corresponding microstructures are shown in Figure 2.
  • This example shows that the steel is amenable for processing to bainitic transformation after thermo-mechanical processing over a wide range of temperatures. This implies that the steel exhibits bainitic structure with lesser control of cooling rate. This simplifies the manufacturing process in closed die forging where in some cases desired cooling rate is imposed to get a specific microstructure.
  • the present invention confirms that there is no need for forced air cooling or a very controlled cooling in the conveyor after deformation.
  • the steel made using the process of invention was used in making of close die steel component, where excellent consistency in mechanical properties is achieved.
  • the mechanical properties obtained in this study shows ultra-high strength range consistent in a product. Such levels of properties are usually achieved in hardened and tempered steels. In the case of the present invention, there is no need for hardening and tempering and air cooling is sufficient to achieve the desired mechanical properties. It was also observed that the transverse properties as shown in Table 2 significantly improved when the steel was subject to thermo- mechanical processing in a closed die forging operation.
  • the steel bar manufactured using the invented process are easy to forge into complex shaped components.
  • the forging made of such steel had the desired bainitic structure.
  • This ultra-high strength steel contributes to weight reduction of the existing components that enhances fuel efficiency in automotive type applications.
  • the component weight reduction can be achieved by at least 10%.
  • the steel made using the process of invention was used for forging an automotive front axle beam designed for Gross Axle Weight Rating (GAWR) of about 7 tons as shown in Figure 3.
  • GAWR Gross Axle Weight Rating
  • the closed die forging of components made using the steel of the invention can be manufactured using a hammer or a press, and the forging process involves soaking of rolled bar at a temperature range between 1280° C and 1220° C , The Finish forging temperature is maintained within temperature range 1000 to 900°C.
  • the forging process involves preform manufacturing step for blocker forging and finisher forging, the process of preform manufacturing consist of reduce rolling the heated billet and bending some portion using bender tool.
  • the finish forging is followed by cooling the hot forged component in any of the cooling medium selected from a group comprising controlled cooled, air, oil, or polymer.
  • the microstructure of forging component using the ultra-high strength steel is as shown in Figure 4. It should be noted that the steps of forging process disclosed in the example above are specific to the axle beam type components. Forging process for other types of components manufactured using the steel of the invention may vary depending on component geometry.
  • the mechanical properties and fatigue testing of the beam was carried out. The mechanical properties and the performance of the steel are as given in Table 3.
  • Table 3 Typical mechanical property performance of the steel of the
  • the fatigue test results shows at least five times better fatigue life as compared to conventional heat treated steel grades such as AISI 1045, 40Cr4.
  • Axle beams made from the invention of the present steel can be made slimmer than those made with micro alloyed steel grades (30MnVS6+Ti) resulting in weight reduction.
  • the steel shows dense sheaves of bainitic ferrite with nano-carbides.
  • the strengths developed in this invention far surpass the traditional medium carbon microalloyed steel grades used for component fabrication.
  • One key feature of the process of the present invention is that the enhanced strength of the steel disclosed herein is achieved without heat treatment by cooling in air or cooling in other media after thermo-mechanical processing.
  • the mechanical properties of the steel of the invention are comparable to that in the oil hardened and tempered alloy steels and superior to that obtained in ferrite pearlitic medium carbon microalloyed steel.
  • the present steel achieves the strength value merely using thermo-mechanical processes and with suitable cooling medium.
  • the steel of the present invention is comparable with 1% Cr alloy steel in terms of cost but it has mechanical properties which are equivalent to alloy steels with further alloying additive and heat treatment.
  • the enhanced strength enables reduction in weight of the components in range of at least 10 % in case of the traditional medium carbon micro alloyed steel.
  • the improved strength values have resulted in improved fatigue life of components made from the steel of the present invention is at least 5 times when compared with those which were made using traditional micro alloyed steel grade.
  • the steel of the present invention is useful for light-weighting opportunities in applications such as shafts, axle beams, steering knuckles, connecting rods, camshaft, etc.
  • the present invention has the following aspects and advantages:
  • a robust chemistry of the steel was developed from as-cast ingot or concast product which can be hot forged or hot rolled followed by controlled cooling in media such as vermiculite cooling, air cooling, oil cooling or polymer show ferrite-carbidic bainitic microstructure that exhibits ultra high strength levels with good ductility and reasonable toughness.
  • the steel has a composition in weight percentage Carbon of 0.1 to 0.25 % , Manganese 1.2 to 2.5 % Silicon of 0.5 to 1.7 % , Chromium of 0.8 to 1.4 % , Molybdenum of 0.05 to 0.1 wt.%, Niobium of 0.05 to 0.10 wt.%, Titanium of 0.01 to 0.03 wt.% and Boron between 30 ppm, with residual elements such as Nickel, Vanadium, Sulphur and Phosphorous permissible in the following proportions: Nickel less than 0.4 % , Vanadium up to 0.1 wt. % , Sulphur less than 0.03 % , and Phosphorus less than 0.02 % . Further the Oxygen is maintained at a level of less than 15 ppm to ensure cleanliness for the ultra-high strength range.
  • the steel which is thermo-mechanically processed and can be subject to a wide variety of cooling condition to give bainitic structure namely vermiculite cooling, air cooling, oil cooling, polymer quenching or water quenching exhibit bainitic structure and a wide variety of properties in the ultra high strength range with good ductility and reasonable toughness.
  • the steel could be manufactured in large tonnages and present study has resulted in a 35 MT electric arc furnace steel making furnace followed by continuous casting and it could be hot forged and hot rolled without defects at a temperature range between 850 and 1280°C.
  • the steel developed was extensively studied for mechanical properties in as-rolled, as-forged and closed die forging condition followed by air cooling where excellent Ultra high strength- ductility properties could be achieved.
  • the components like front axle beam have been analysed for fatigue performance.
  • the steel shows at least five times the fatigue life of the corresponding alloy steel component.
  • the steel developed has a potential opportunity to replace expensive alloy steels processed by quenching and tempering treatment and produce lightweight component with better strength to weight ratio. Weight reduction of structural component of at least 10 % can be achieved.
  • An ultra-high strength steel of present invention characterised in that the said steel comprises in weight percentage carbon in the proportion of 0.1 to
  • a process of making an ultra-high strength steel comprising the steps of:
  • thermo-mechanical processing said cast steel by hot charging the as-cast ingot or the continuously cast bloom, or alternatively, cold-charging them in a furnace for further deformation,
  • finish forging the component at a temperature range 1000 to 900°C cooling the finish forged component in any of the cooling medium selected from a group comprising controlled cooled, air, oil, or polymer.
  • thermo-mechanical processing is carried out by a technique selected from a group comprising hot rolling, or closed die forging, or extrusion.
  • a process of making forged components as disclosed in embodiment 3, wherein the step of hot forging of component comprises the steps of preform manufacturing for blocker forging and finisher forging, followed by cooling. 7.
  • a process of making forged components as disclosed in embodiment 6 wherein the step of preform manufacturing comprises the steps of reduce rolling and bending.

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

Abstract

La présente invention concerne un acier à très haute résistance pour des éléments structuraux, un procédé de fabrication d'un tel acier qui a une microstructure souhaitable dans des conditions de traitement thermomécanique et de refroidissement différent qui permet d'obtenir une haute performance à la fatigue en service et un procédé de fabrication d'éléments forgés à utilisant un tel acier. L'acier et le procédé pour sa fabrication permettent la fabrication d'éléments qui présentent une microstructure bainitique qui confère des plages de très haute résistance avec une très haute performance à la fatigue. L'invention permet d'économiser des additifs d'alliage par comparaison avec des aciers d'alliage trempés et revenus et de plus d'éviter des opérations de traitement thermique onéreuses pour obtenir la plage de propriétés mécaniques souhaitée. L'acier selon l'invention est un produit de remplacement approprié de barres en acier microallié ou en acier traité thermiquement utilisées pour la production d'éléments structuraux. L'acier peut être utilisé pour être appliqué en tant que produits longs laminés à chaud et refroidis à l'air qui peuvent être directement utilisés pour des applications ou il peut être directement forgé à chaud en forgeage en matrice ouverte ou fermée suivi d'un refroidissement commandé pour obtenir la microstructure et la plage de propriétés mécaniques souhaitées.
EP15808458.2A 2014-10-21 2015-10-21 Acier traité thermomécaniquement à très haute résistance Active EP3209806B1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
IN3355MU2014 2014-10-21
PCT/IB2015/058107 WO2016063224A1 (fr) 2014-10-21 2015-10-21 Acier traité thermomécaniquement à très haute résistance

Publications (2)

Publication Number Publication Date
EP3209806A1 true EP3209806A1 (fr) 2017-08-30
EP3209806B1 EP3209806B1 (fr) 2020-11-25

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Country Status (4)

Country Link
US (1) US20170369976A1 (fr)
EP (1) EP3209806B1 (fr)
HU (1) HUE052776T2 (fr)
WO (1) WO2016063224A1 (fr)

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EP3592871A1 (fr) * 2017-03-10 2020-01-15 Tata Steel Limited Produit en acier laminé à chaud ayant une résistance ultra-élevée d'au moins 1100 mpa et un bon allongement de 21 %
CN109986011A (zh) 2018-01-02 2019-07-09 通用电气公司 锻造头、锻造装置以及增材制造系统
WO2019180492A1 (fr) 2018-03-23 2019-09-26 Arcelormittal Pièce forgée en acier bainitique et son procédé de fabrication
US20230323493A1 (en) 2020-09-07 2023-10-12 Arcelormittal Forged part of steel and a method of manufacturing thereof
CN113444978B (zh) * 2021-06-29 2023-02-21 钢铁研究总院 一种超高强度钢的制备方法
CN113528763A (zh) * 2021-07-20 2021-10-22 苏州雷格姆海洋石油设备科技有限公司 超高强度大壁厚水下采油树井口连接器锻件的生产工艺
WO2024121606A1 (fr) * 2022-12-08 2024-06-13 Arcelormittal Acier forgé et laminé à chaud et son procédé de fabrication
CN116384159B (zh) * 2023-05-29 2023-08-22 北京科技大学 一种连铸工艺温度仿真和宏观组织预测的方法及系统

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Publication number Priority date Publication date Assignee Title
FR2741632B1 (fr) * 1995-11-27 1997-12-26 Ascometal Sa Acier pour la fabrication d'une piece forgee ayant une structure bainitique et procede de fabrication d'une piece
JPH09241750A (ja) * 1996-03-06 1997-09-16 Hino Motors Ltd 熱処理歪みの小さい肌焼きボロン鋼歯車の製造方法
FR2847910B1 (fr) * 2002-12-03 2006-06-02 Ascometal Sa Procede de fabrication d'une piece forgee en acier et piece ainsi obtenue.
CN101613830B (zh) * 2008-06-27 2012-08-29 鞍钢股份有限公司 一种热轧贝氏体钢轨及生产工艺
JP5402711B2 (ja) * 2010-02-17 2014-01-29 新日鐵住金株式会社 浸炭窒化層を有する鋼製品およびその製造方法
JP5533712B2 (ja) * 2011-02-03 2014-06-25 新日鐵住金株式会社 表面硬化用熱間加工鋼材

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EP3209806B1 (fr) 2020-11-25

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