WO2023067544A1 - Acier laminé à chaud faiblement allié de haute dureté et son procédé de fabrication - Google Patents

Acier laminé à chaud faiblement allié de haute dureté et son procédé de fabrication Download PDF

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Publication number
WO2023067544A1
WO2023067544A1 PCT/IB2022/060094 IB2022060094W WO2023067544A1 WO 2023067544 A1 WO2023067544 A1 WO 2023067544A1 IB 2022060094 W IB2022060094 W IB 2022060094W WO 2023067544 A1 WO2023067544 A1 WO 2023067544A1
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Prior art keywords
hot rolled
rolled steel
high hardness
alloyed hot
low alloyed
Prior art date
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PCT/IB2022/060094
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English (en)
Inventor
Chiradeep Ghosh
Rahul Kumar
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Tata Steel Limited
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Publication of WO2023067544A1 publication Critical patent/WO2023067544A1/fr

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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
    • C22C38/40—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
    • 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
    • C21D1/18—Hardening; Quenching with or without subsequent tempering
    • 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
    • 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
    • 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
    • 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
    • C22C38/06—Ferrous alloys, e.g. steel alloys containing aluminium
    • 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
    • C22C38/46—Ferrous alloys, e.g. steel alloys containing chromium with nickel with vanadium
    • 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

Definitions

  • the present invention relates to a high hardness low alloyed hot rolled steel, and more particularly to the high hardness wear resistant hot rolled steel having improved abrasion resistance and impact toughness, and method of manufacturing the high hardness low alloyed hot rolled steel.
  • Wear involves gradual decay of material from any surface due to relative motion between the active and counter body species. This can either happen due to mechanical action or chemical reaction.
  • abrasive wear resistant material is of high demand. Surprisingly, the abrasive wear alone contributes as high as 63% of the total wear loss, which is undesirable. With better design or by selecting some alternative materials, this can be reduced to a great extent.
  • a new design of a component is often coupled with other associated risks, and also does not always make an economically viable alternative. In contrary, selecting a better material sometime considered as a better option.
  • Another objective of the present invention is to provide a high hardness low alloyed hot rolled steel sheet, having the following composition in weight%: C: 0.10-0.25, Mn: 1.05-1.5, Si: 0.25-0.35, Cr: 0.15-0.25, Mo: 0.05-0.15, Ni: 0.45- 0.55, Al: 0.15-0.25, carbon equivalent: 0.34-0.69, and the balance being Iron (Fe) and unavoidable impurities and a microstructure consisting of ferrite, austenite, pearlite, bainite and martensite.
  • Another objective of present invention is to produce a method to manufacture the high hardness low alloyed hot rolled steel possessing sufficient amount of martensite by controlling cooling rate after finish rolling in the run-outtable (ROT) during hot rolling operation.
  • ROT run-outtable
  • Another objective of present invention is to estimate the saturation cooling rate to obtain the maximum possible hardness in the said composition range.
  • It is yet another objective of the present invention, is to provide new easier manufacturing method combining thermomechanical, and heat treatment processes for the proposed chemical composition to manufacture the high hardness low alloyed hot rolled steel having improved abrasion resistance, impact toughness, hardness, and weldability.
  • the high hardness low alloyed hot rolled steel comprises the following composition expressed in weight %: Carbon (C): 0.10% - 0.25%, Manganese (Mn): 1.05% - 1.5%, Chromium (Cr): 0.15-0.25%, Silicon (Si): 0.25%- 0.35%, Nickel (Ni): 0.45%-0.55%, Aluminium (Al): 0.15-0.25%, Molybdenum (Mo): 0.05%-0.15%, Vanadium: maximum 0.03%, carbon equivalent: 0.34 - 0.69 and the remaining being substantially iron and incidental impurities.
  • the high hardness low alloyed hot rolled steel comprises a microstructure of maximum 10 % ferrite, maximum 10% austenite, maximum 20% pearlite, maximum 20% bainite and 60 -100 % martensite.
  • the high hardness low alloyed hot rolled steel has a hardness (HV 1 kg) > 200 Hv. In an embodiment, the high hardness low alloyed hot rolled steel has hardness (HV 1 kg) in the range of 200 - 460 Hv.
  • the high hardness low alloyed hot rolled steel has a tensile strength > 600 MPa. In an embodiment, the high hardness low alloyed hot rolled steel has a yield strength > 500 MPa. In an embodiment, the high hardness low alloyed hot rolled steel has total elongation in range 10 to 20%.
  • the Mn content of the high hardness low alloyed hot rolled steel is kept below 1.8 wt.% to avoid center-line segregation.
  • the C content in the high hardness low alloyed hot rolled steel helps in stabilizing the austenite at room temperature.
  • the Si content of the high hardness low alloyed hot rolled steel is kept in the range between 0.25- 0.35 wt.% to partially retard cementite formation.
  • the high hardness low alloyed hot rolled steel comprises the composition expressed in weight %: C - 0.15, Mn - 1.1, Si - 0.3, Cr - 0.2, V - 0.03, Ni - 0.5, Al - 0.2, Mo - 0.1, carbon equivalent 0.43 and the balance being Iron (Fe) and unavoidable impurities.
  • the high hardness low alloyed hot rolled steel comprises the composition expressed in weight %: C - 0.21, Mn - 1.47, Si - 0.3, Cr - 0.2, Ni - 0.5, Mo - 0.1, carbon equivalent 0.55, and the balance being Iron (Fe) and unavoidable impurities.
  • the high hardness low alloyed hot rolled steel has hardness (HV 1kg) in the range of 220-380 Hv.
  • the high hardness low alloyed hot rolled steel has hardness (HV 1kg) in the range of 300-460 Hv.
  • a method for manufacturing high hardness low alloyed hot rolled steel sheet comprises casting steel slab having a composition expressed in weight %: C: 0.10-0.25, Mn: 1.05-1.5, Si: 0.25-0.35, Cr: 0.15-0.25, Mo: 0.05-0.15, Ni: 0.45-0.55, Al: 0.15-0.25, carbon equivalent: 0.34-0.69, and the balance being Iron (Fe) and unavoidable impurities.
  • the method also comprises reheating the steel slab to a temperature greater than 1150°C.
  • the method further comprises hot rolling the steel slab to about 70% deformation to produce a steel sheet such that finish rolling is done at a temperature (TERT).
  • the TFRT varies in the range 830°C to 890°C.
  • the method comprises cooling at a cooling rate in the range of 5°C/s - 60°C/s till a room temperature is reached to obtain the high hardness low alloyed hot rolled steel sheet.
  • the high hardness low alloyed hot rolled steel comprises a microstructure of maximum 10 % ferrite, maximum 10% austenite, maximum 20% pearlite, maximum 20% bainite and 60 -100 % martensite.
  • the high hardness low alloyed hot rolled steel has a tensile strength > 600 MPa and yield strength > 500 MPa, total elongation in range 10 to 20%.
  • the TFRT is 870°C.
  • the high hardness low alloyed hot rolled steel comprises the composition expressed in weight %: C - 0.15, Mn - 1.1, Si - 0.3, Cr - 0.2, V - 0.03, Ni - 0.5, Al - 0.2, Mo - 0.1, carbon equivalent 0.43, and the balance being Iron (Fe) and unavoidable impurities.
  • the high hardness low alloyed hot rolled steel comprises the composition expressed in weight %: C - 0.21, Mn - 1.47, Si - 0.3, Cr - 0.2, Ni - 0.5, Mo - 0.1, carbon equivalent 0.55, and the balance being Iron (Fe) and unavoidable impurities.
  • the high hardness low alloyed hot rolled steel has hardness (HV 1kg) in the range of 220-380 Hv.
  • the high hardness low alloyed hot rolled steel has hardness (HV 1kg) in the range of 300-460 Hv.
  • the saturation cooling rate exists for the high hardness low alloyed hot rolled steel in the range of 20-30 °C/s.
  • the maximum hardness (HV 1kg) high hardness low alloyed hot rolled steel is in the range of 360-380 Hv.
  • the maximum hardness (HV 1kg) of the high hardness low alloyed hot rolled steel is in the range of 450-460 Hv.
  • the steel slab is reheated to a temperature between 1150°C - 1250°C for a duration of 20 minutes to 2 hours depending on the slab thickness.
  • the thickness of the steel sheet is in the range of 4 mm - 8 mm.
  • a component produced from the high hardness low alloyed hot rolled steel is used in structural as well as wear resistant applications of the L&E equipment, particularly used in mining and earthmoving applications.
  • Figure 1 illustrates a flowchart of a method of manufacturing a high hardness low alloyed hot rolled steel sheet, according to an embodiment of the present invention
  • Figure 2 illustrates a schematic diagram of cooling technique followed after rolling (in the run-out table of the hot-strip mill) during manufacture of the high hardness low alloyed hot rolled steel sheet, according to the embodiment of the present invention
  • Figure 3 illustrates a graphical representation of variation of hardness versus cooling rates of examples (steel 1 and steel 2) of the high hardness low alloyed hot rolled steel, according to the embodiments of present invention.
  • the high hardness low alloyed hot rolled steel having a minimum tensile strength of 600 MPa comprises the following composition expressed in weight %: C: 0.10-0.25, Mn: 1.05-1.5, Si: 0.25-0.35, Cr: 0.15-0.25, Mo: 0.05-0.15, Ni: 0.45-0.55, Al: 0.15-0.25, carbon equivalent: 0.34- 0.69, and the balance being Iron (Fe) and unavoidable impurities.
  • the high hardness low alloyed hot rolled steel comprises a microstructure of maximum 10 % ferrite, maximum 10% austenite, maximum 20% pearlite, maximum 20% bainite and 60 -100 % martensite.
  • the high hardness low alloyed hot rolled steel has a hardness > 200 Hv.
  • the high hardness low alloyed hot rolled steel has a hardness in the range of 200-460 Hv.
  • the high hardness low alloyed hot rolled steel has a yield strength > 500 MPa, and total elongation in the range between 10- 20%.
  • the high hardness low alloyed hot rolled steel has improved abrasion resistance, impact toughness, hardness, and weldability.
  • the high hardness low alloyed hot rolled steel comprises the composition expressed in weight %: C - 0.15, Mn - 1.1, Si - 0.3, Cr - 0.2, V - 0.03, Ni - 0.5, Al - 0.2, Mo - 0.1, carbon equivalent 0.43 and the balance being Iron (Fe) and unavoidable impurities.
  • the high hardness low alloyed hot rolled steel has hardness (HV 1kg) in the range of 220-380 Hv.
  • the high hardness low alloyed hot rolled steel comprises the composition expressed in weight %: C - 0.21, Mn - 1.47, Si - 0.3, Cr - 0.2, Ni - 0.5, Mo - 0.1, carbon equivalent 0.55, and the balance being Iron (Fe) and unavoidable impurities.
  • the high hardness low alloyed hot rolled steel has hardness (HV 1kg) in the range of 300-460 Hv.
  • the martensite in the microstructure provides excellent resistance to abrasive wear and improves the impact toughness.
  • the high hardness low alloyed hot rolled steel is suitable for producing components to be used in structural as well as wear resistant applications of the Lifting & Excavating equipment, particularly used in mining and earthmoving applications.
  • the method (100) of manufacturing the high hardness low alloyed hot rolled steel sheet of the desired composition comprises casting molten steel having composition expressed in weight %: C: 0.10-0.25, Mn: 1.05-1.5, Si: 0.25-0.35, Cr: 0.15-0.25, Mo: 0.05-0.15, Ni: 0.45-0.55, Al: 0.15-0.25, carbon equivalent: 0.34-0.69, and the balance being Iron (Fe) and unavoidable impurities.
  • the molten steel is cast in a casting apparatus to obtain steel slabs (cast ingots). In the illustrated example, the steel is cast either in a conventional continuous caster or thin-slab caster.
  • the method (100) comprises reheating the steel slab (steel casting) to a temperature greater than 1150°C.
  • the slab is reheated to temperature ranging between 1150 to 1250°C for a duration of 20 minutes to 2 hours depending on the slab thickness.
  • a reheating temperature greater than 1250°C is also undesirable because it may lead to excessive grain coarsening of austenite and/or scale loss.
  • the method (100) comprises hot rolling the steel slab to about 70% deformation to produce a steel sheet such that finish rolling is done at a temperature (TFRT).
  • TFRT temperature
  • the TFRT is varied in the range 830°C to 890°C, more preferably 870°C.
  • the slabs of higher thicknesses are rough rolled in roughing stands in a conventional hot-rolling mill.
  • the rough rolling is done above the recrystallization temperature.
  • the finish rolling is carried out in a 6 or 7 stands tandem rolling mill.
  • the rolling is finished at the finish rolling temperature, TFRT given by such that 830 ⁇ TFRT ⁇ 890°C.
  • the above range of the finish rolling temperature (TFRT) is chosen to finish the hot rolling in the austenitic range.
  • the TFRT is kept below T m to exploit the thermo-mechanical controlled rolling.
  • the method (100) comprises cooling at a cooling rate in the range of 5°C/s - 60°C/s till a room temperature is reached to obtain the high hardness low alloyed hot rolled steel sheet.
  • the cooling rate is kept between 5°C/s - 60°C/s so as to ensure sufficient amount of martensite formation in the microstructure.
  • the steel is cooled to allow development of higher amount of martensite in the final microstructure, which will give rise to the improved abrasion resistance, impact toughness, hardness, and weldability.
  • the obtained high hardness low alloyed hot rolled steel sheet has microstructure represented by, in area%, maximum 10 % ferrite, maximum 10% austenite, maximum 20% pearlite, maximum 20% bainite and 60 -100 % martensite.
  • the high hardness low alloyed hot rolled steel has a hardness > 200 Hv. More particularly, in the range of 200-460 Hv.
  • the high hardness low alloyed hot rolled steel sheet exhibits tensile strength greater than 600 MPa, total elongation in the range of 10-20%, and yield strength greater than 500 MPa.
  • the thickness of the steel sheet is in the range of 4 mm - 8 mm.
  • the disclosed invention method (100) it is possible to manufacture the high hardness hot-rolled steel sheet with a minimum 600 MPa tensile strength consisting of ferrite + pearlite + bainite + austenite + martensite microstructure which has improved abrasion resistance, impact toughness, hardness, and weldability.
  • a steel sheet is suited for producing components to be used in structural as well as wear resistant applications of the L&E equipment, particularly used in mining and earthmoving applications where good abrasive wear resistance and impact toughness is a requirement along with the high hardness.
  • C 0.10-0.25%: The presence of carbon is inevitable in any commercial steel. Carbon is added to control the strength of the steel. Depending on the final requirement, the weight percentage of the carbon addition changes. After quenching from the austenitic region to the partitioning temperature, the microstructure mainly constitutes of austenite and martensite. Depending on the partitioning temperature and composition of the base steel, carbon gets rejected from the supersaturated martensite. This carbon migrates from martensite to austenite. As a result of the carbon enrichment of the austenite, the stability of this phase increases. Afterwards, at room temperature the presence of austenite in the microstructure can also be visible. This austenite improves the mechanical property of the steel.
  • Si 0.25-0.35%: Si is added during steel making process as an effective deoxidizer. Additionally, Si is a very efficient solid solution strengthener. Furthermore, cementite precipitation can be retarded to a large extent by Si. This is attributed to the build-up of Si in front of the advancing cementite/matrix interface. Since Si has little solubility in cementite, it is rejected by a growing cementite particle causing an enrichment of Si at the interface. Now for the continuous precipitation, Si should diffuse away from the interface. This does not happen. As a consequence, this creates a favourable situation for carbon partitioning to take place instead of carbide precipitation. However, higher amount of Si in steel creates some operational issue in terms of surface appearance of the steel.
  • Al 0.15-0.25%: Al is also added in molten steel as a deoxidizer. The presence of nitrogen in steel creates an environment to form AIN precipitate. This precipitate limits the grain growth during reheating of the steel slab before hot rolling. Furthermore, like Si, Al also exhibits to suppress the carbide precipitation in steel. However, it does not create any operational hindrance during hot rolling. Therefore, in the current context Al is added between 0.15-0.25 wt.%.
  • Mn 1.05-1.50%: Mn is a mild solid solution strengthener. It decreases the ductile to brittle transition temperature. More importantly Mn is an austenite stabilizer. It delays the austenite decomposition during accelerated cooling. As a consequence, finish rolling can be performed more effectively in the austenitic region and more amount of deformation can be imparted. This creates a finer ferrite grain size which in turn increases the strength of the steel. However, at higher Mn content there is always a chance for centerline segregation in the steel due to low diffusivity of Mn. Therefore, in the present context Mn content is restricted between 1.05-1.50 wt.%.
  • Cr 0.15-0.25%: Cr improves the hardenability of the steel to a large extent. It retards the formation of pearlite during continuous cooling from the austenite region. Thus, helps in formation of the martensite event at a nominal cooling rate. Therefore, the Cr content is restricted between 0.15-0.25 wt.%.
  • Mo 0.05-0.15%: Mo is also added to primarily to improve the hardenability of the steel. Although Mo impairs the bainite formation to a certain extent, it retards the pearlite formation to a much greater degree. Considering this, Mo is added in the range of 0.05-0.15 wt.%.
  • Ni 0.45-0.55%: Ni is primarily added in steel to improve the fracture toughness. Ni induces grain refinement by reducing the transformation temperature. This in turn increases the number of grain boundaries which is responsible for better fracture toughness properties. Keeping this in mind Ni has been added in the range 0.45-0.55 wt.% in the current context.
  • V 0.03% or less: V forms VN/VC in the ferrite region thereby increases the strength of the material. This is the reason for V addition in the current steel.
  • Microstructure The final set of desired properties in the high hardness low alloyed hot-rolled steel is achieved by the presence of ferrite, bainite, pearlite, austenite and martensite. All the hot-rolling, controlled cooling and coiling conditions have significance in achieving the final microstructure and properties. The contribution of the each of the phases i.e. ferrite, pearlite, austenite, bainite and martensite are described below.
  • Ferrite The final hot-rolled microstructure contains a small amount 10% ferrite, which is strengthened by the contributions from the alloying elements mentioned above.
  • Pearlite A small amount of fine pearlite (20% maximum) is observed in the final microstructure. A small amount of fine pearlite imparts strength in the final microstructure.
  • Austenite A small amount of austenite (10% maximum) is observed in the final microstructure. This is essential to impart toughness in the final product.
  • Bainite A small amount of bainite (20% maximum) is observed in the final microstructure. This contributes towards the final strength and toughness of the product.
  • Martensite The final hot-rolled microstructure contains 60-100% martensite.
  • the martensite in the microstructure ensures the hardness of 200-460 Hv is achieved in the final hot-rolled steel sheet.
  • Table -2 Variation in hardness with cooling rate.
  • the present invention provides the high hardness low alloyed hot rolled steel having improved abrasion resistance, impact toughness, hardness, and weldability.
  • the martensite present in the microstructure provides higher hardness for the produced steel.
  • the disclosed steel is suitable for producing components to be used in structural as well as wear resistant applications of the L&E equipment, particularly used in mining and earthmoving applications.
  • the invention also provides a method to manufacture the high hardness low alloyed hot rolled steel having higher amount of martensite by controlling cooling rate after finish rolling in the run-out-table (ROT) during hot rolling operation.
  • the high hardness low alloyed hot rolled steel makes an important contribution towards durable, cost effective, futuristic and strategic application of steel with greater factor of safety. Further the steel having high hardness and good wear resistance may be used in the sectors of engineering, mining, construction, agriculture, port, electric power and metallurgy etc.

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

Abstract

L'invention concerne un acier laminé à chaud faiblement allié de haute dureté affichant une résistance à l'abrasion, une ténacité à l'impact, une dureté et une soudabilité améliorées. L'acier laminé à chaud faiblement allié de haute dureté a la composition suivante exprimée en % en poids : C : de 0,10 à 0,25, Mn : de 1,05 à 1,5 ; Si : de 0,25 à 0,35, Cr : de 0,15 à 0,25 ; Mo : de 0,05 à 0,15 ; Ni : de 0,45 à 0,55, Al : de 0,15 à 0,25, équivalent carbone : de 0,34 à 0,69, et le reste étant du fer (Fe) et des impuretés inévitables. L'acier laminé à chaud faiblement allié de haute dureté a une microstructure de 10 % de ferrite au maximum, de 10 % d'austénite au maximum, de 20 % de perlite au maximum, de 20 % de bainite au maximum et de 60 à 100 % de martensite. L'acier laminé à chaud faiblement allié de haute dureté a une résistance à la traction ≥ 600 MPa, un allongement total de 10 à 20 %, une dureté ≥ 200 Hv, et une limite d'élasticité ≥ 500 MPa. L'invention concerne également un procédé (100) de fabrication d'une bande d'acier laminé à chaud faiblement allié de haute dureté de la composition susmentionnée.
PCT/IB2022/060094 2021-10-20 2022-10-20 Acier laminé à chaud faiblement allié de haute dureté et son procédé de fabrication WO2023067544A1 (fr)

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EP3653736A1 (fr) * 2018-11-14 2020-05-20 SSAB Technology AB Bande d'acier laminé à chaud et procédé de fabrication
EP3719149A1 (fr) * 2019-04-05 2020-10-07 SSAB Technology AB Produit d'acier à dureté élevée et son procédé de fabrication

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2789699A1 (fr) * 2013-08-30 2014-10-15 Rautaruukki Oy Produit d'acier laminé à chaud de grande dureté et procédé de fabrication de celui-ci
EP3653736A1 (fr) * 2018-11-14 2020-05-20 SSAB Technology AB Bande d'acier laminé à chaud et procédé de fabrication
EP3719149A1 (fr) * 2019-04-05 2020-10-07 SSAB Technology AB Produit d'acier à dureté élevée et son procédé de fabrication

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