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CN-117026072-B - Steel sheet for hot stamping, method for producing same, and hot stamped member and method for producing same

CN117026072BCN 117026072 BCN117026072 BCN 117026072BCN-117026072-B

Abstract

The present invention relates to a steel sheet for hot stamping and a method for producing the same, and a hot stamped member and a method for producing the same. The steel sheet for hot stamping of the present invention has a predetermined composition, and has a steel structure comprising ferrite and cementite, wherein Mn concentration of the ferrite and cementite is such that Mn [ theta ]/Mn [ alpha ] is 1.4 or more when Mn [ alpha ] [ theta ] and Mn [ theta ] are respectively defined.

Inventors

  • NAKAGAWA KOICHI
  • TAMAI YOSHIKIYO

Assignees

  • 杰富意钢铁株式会社

Dates

Publication Date
20260505
Application Date
20170113
Priority Date
20160329

Claims (20)

  1. 1. A steel sheet for hot stamping, which comprises, in mass%, 0.180% or more and less than 0.300% of C, 3.50% or more and less than 11.0% of Mn, 0.01 to 1.5% of Si, 0.05% or less of P, 0.05% or less of S, 0.005 to 0.1% of Al, 0.01% or less of N, 0.002 to 0.03% of Sb, and 0.005 to 3.0% of W, with the balance being Fe and unavoidable impurities, And has a structure comprising 92.00% to 99.0% ferrite, 1.0% to 5.0% cementite, and 5.0% or less balance of a structure, wherein the balance of the structure is selected from bainite and pearlite, and Mn is enriched in cementite when Mn concentrations of the ferrite and cementite are Mn alpha and Mn alpha, respectively, wherein Mn theta/Mn alpha is 1.4 or more.
  2. 2. The steel sheet for hot stamping according to claim 1, wherein the composition further comprises one or more selected from the following groups A to D in mass%, Group A is one or more selected from Ni 0.01-5.0%, cu 0.01-5.0%, cr 0.01-5.0% and Mo 0.01-3.0%, Group B is one or more than two selected from 0.005-3.0% of Ti, 0.005-3.0% of Nb and 0.005-3.0% of V, Group C is one or more selected from REM 0.0005-0.01%, ca 0.0005-0.01% and Mg 0.0005-0.01%, And 0.0005-0.05% of group D.
  3. 3. The steel sheet for hot stamping as set forth in claim 1 or 2, wherein a plating layer is provided on a surface thereof.
  4. 4. The steel sheet for hot stamping as set forth in claim 3, wherein the plating layer is a Zn-based plating layer or an Al-based plating layer.
  5. 5. The steel sheet for hot stamping as claimed in claim 4, wherein the Zn-based coating layer contains Ni in an amount of 10 to 25 mass%.
  6. 6. A method for producing a steel sheet for hot stamping, wherein a steel sheet having a composition comprising, in mass%, 0.180% or more and less than 0.300% of C, 3.50% or more and less than 11.0% of Mn, 0.01 to 1.5% of Si, 0.05% or less of P, 0.05% or less of S, 0.005 to 0.1% of Al, 0.01% or less of N, 0.002 to 0.03% of Sb and 0.005 to 3.0% of W, the balance being Fe and unavoidable impurities is heated, hot rolled, and coiled into a coil-like shape at a coiling temperature of 650 ℃ to 750 ℃ or more in a temperature range of 950 ℃ or more, the hot rolled steel sheet is cold rolled at a reduction rate of 30% or more and 85% or less to produce a cold rolled steel sheet, and further the cold rolled steel sheet is heated to a temperature range of 39 ℃ to 150 ℃ to 5310 ℃ or more and cooled at a temperature range of 5310 ℃ or less after heating the cold rolled steel sheet to a temperature range of 39 ℃ to 150 ℃ to 5310 ℃ or less.
  7. 7. The method for producing a steel sheet for hot stamping as claimed in claim 6, wherein the composition further comprises one or more selected from the group A to D, Group A is one or more selected from Ni 0.01-5.0%, cu 0.01-5.0%, cr 0.01-5.0% and Mo 0.01-3.0%, Group B is one or more than two selected from 0.005-3.0% of Ti, 0.005-3.0% of Nb and 0.005-3.0% of V, Group C is one or more selected from REM 0.0005-0.01%, ca 0.0005-0.01% and Mg 0.0005-0.01%, And 0.0005-0.05% of group D.
  8. 8. The method for manufacturing a steel sheet for hot stamping according to claim 6 or 7, wherein a plating layer is formed on the surface of the steel sheet for hot stamping after the annealing.
  9. 9. The method for producing a steel sheet for hot stamping as claimed in claim 8, wherein the plating layer is a Zn-based plating layer or an Al-based plating layer.
  10. 10. The method for producing a steel sheet for hot stamping as claimed in claim 9, wherein the Zn-based plating layer contains 10-25 mass% Ni.
  11. 11. The method for producing a steel sheet for hot stamping as claimed in claim 8, wherein an adhesion amount of the plating layer is 10 to 90g/m 2 per one side.
  12. 12. The method for producing a steel sheet for hot stamping as claimed in claim 9, wherein an adhesion amount of the plating layer is 10 to 90g/m 2 per one side.
  13. 13. The method for producing a steel sheet for hot stamping as claimed in claim 10, wherein an adhesion amount of the plating layer is 10 to 90g/m 2 per one side.
  14. 14. A hot stamping member comprising, in mass%, 0.180% or more and less than 0.300% of C, 3.50% or more and less than 11.0% of Mn, 0.01 to 1.5% of Si, 0.05% or less of P, 0.05% or less of S, 0.005 to 0.1% of Al, 0.01% or less of N, 0.002 to 0.03% of Sb and 0.005 to 3.0% of W, the balance being Fe and unavoidable impurities, And has a structure in which martensite is 70.0% or more by volume and retained austenite is 3.0% or more and 30.0% or less by volume, and retained austenite having an equivalent circular diameter of 0.3 μm or more is present at 2.0X10 5 pieces/mm 2 or more, The hot stamping member is obtained by hot stamping a steel sheet as a raw material, wherein the steel sheet has a structure composed of 92.00% to 99.0% ferrite, 1.0% to 5.0% cementite, and 5.0% or less balance of structure, wherein the balance of structure is selected from bainite and pearlite, and Mn/Mn is 1.4 or more when Mn concentration of the ferrite and Mn/Mn is Mn, respectively, and Mn is enriched in the cementite.
  15. 15. The hot stamping member as claimed in claim 14, wherein the composition further comprises one or more selected from the following groups A to D in mass%, Group A is one or more selected from Ni 0.01-5.0%, cu 0.01-5.0%, cr 0.01-5.0% and Mo 0.01-3.0%, Group B is one or more than two selected from 0.005-3.0% of Ti, 0.005-3.0% of Nb and 0.005-3.0% of V, Group C is one or more selected from REM 0.0005-0.01%, ca 0.0005-0.01% and Mg 0.0005-0.01%, And 0.0005-0.05% of group D.
  16. 16. A hot stamped component according to claim 14 or 15, wherein the surface has a coating.
  17. 17. The hot stamped component of claim 16, wherein the coating is a Zn-based coating or an Al-based coating.
  18. 18. The hot stamped member according to claim 17, wherein the Zn-based plating layer contains 10 to 25 mass% of Ni.
  19. 19. A method of manufacturing a hot stamped component, wherein, A steel sheet is used as a raw material, which comprises, in mass%, 0.180% or more and less than 0.300% of C, 3.50% or more and less than 11.0% of Mn, 0.01 to 1.5% of Si, 0.05% or less of P, 0.05% or less of S, 0.005 to 0.1% of Al, 0.01% or less of N, 0.002 to 0.03% of Sb, and 0.005 to 3.0% of W, the balance being Fe and unavoidable impurities, and which has a structure comprising 92.00% or more and 99.0% or less of ferrite, 1.0% or more and 5.0% or less of cementite, and 5.0% or less of a balance being selected from bainite and pearlite, wherein Mn/Mn alpha is 1.4 or more when Mn is respectively defined as Mn alpha, mn is enriched in Mn, Heating the steel sheet to a temperature range of Ac 3 to 1000 ℃ and holding the steel sheet in the temperature range for 10 to 900 seconds, and then press-forming and quenching the steel sheet simultaneously by using a forming die, A hot stamped member having a structure containing 70.0% or more by volume of martensite and 3.0% or more and 30.0% or less by volume of retained austenite, and having 0.3 μm or more by equivalent circle diameter of 2.0X10 5 pieces/mm 2 or more is obtained.
  20. 20. The method for manufacturing a hot stamping member as described in claim 19, wherein the composition further comprises one or more selected from the following groups A to D in mass%, Group A is one or more selected from Ni 0.01-5.0%, cu 0.01-5.0%, cr 0.01-5.0% and Mo 0.01-3.0%, Group B is one or more than two selected from 0.005-3.0% of Ti, 0.005-3.0% of Nb and 0.005-3.0% of V, Group C is one or more selected from REM 0.0005-0.01%, ca 0.0005-0.01% and Mg 0.0005-0.01%, And 0.0005-0.05% of group D.

Description

Steel sheet for hot stamping, method for producing same, and hot stamped member and method for producing same The present application is a divisional application of the application patent application having a filing date of 2017, 1-13, a filing number of 201780019325.6 (international filing number PCT/JP 2017/001110), and a name of "steel sheet for hot stamping and a method for manufacturing the same, and a hot stamping member and a method for manufacturing the same". Technical Field The present invention relates to a steel sheet for hot press and a method for manufacturing the same, and a hot press member and a method for manufacturing the same. The hot stamping member is a stamping member formed by hot stamping a steel plate. Background In recent years, from the viewpoint of global environment protection, improvement of fuel efficiency of automobiles has been strongly desired. Therefore, weight reduction of the automobile body is demanded. Therefore, in order not to impair safety even if the automotive member is thinned, a steel sheet as a raw material of the automotive member is required to have high strength. However, in general, as the strength of a steel sheet increases, formability decreases, and therefore, in the production of an automobile member using a high-strength steel sheet as a raw material, problems such as difficulty in forming or deterioration in formability occur. In order to solve such a problem, a technique of manufacturing a high-strength automobile member by applying a hot stamping process has been proposed. The hot stamping process is a technique in which a steel sheet is heated to an austenite region and then transferred to a press machine, and the steel sheet is quenched while being formed into a member of a desired shape in a die in the press machine. In addition, in the cooling process (quenching) in the mold, the structure of the member changes from austenite to martensite, whereby a desired shape member of high strength can be obtained. The "hot stamping process (forming)" is also referred to as "hot forming", "hot stamping (hot stamping)", and "press quenching". In addition, recently, from the viewpoint of ensuring safety of passengers, improvement of impact resistance characteristics of automobile members has been desired. In order to meet this demand, it is necessary to improve the ability to absorb energy at the time of collision (impact energy absorbing ability), and from this viewpoint, it is effective to improve the uniform elongation of the automobile member in order to avoid the impact energy absorbing ability from being lowered by breaking the automobile member at the time of collision. Therefore, development of a hot stamped member having high strength and excellent uniform elongation is strongly desired. In order to meet such a demand, for example, patent document 1 discloses a hot-stamped article obtained by stamping a steel sheet by a hot stamping method, which comprises a composition comprising, in mass%, 0.15 to 0.35% of C, 0.5 to 3% of Si, 0.5 to 2% of Mn, 0.05% or less of P, 0.05% or less of S, 0.01 to 0.1% of Al, 0.01 to 1% of Cr, 0.0002 to 0.01% of B, 4 to 0.1% of Ti (N), 0.001 to 0.01% of N, and the balance being Fe and unavoidable impurities, and a structure comprising, in terms of area percentage, 80 to 97% of martensite, 3 to 20% of retained austenite, and 5% or less of the balance being a structure. According to this technique, it is described that the structure of the hot-stamped member can be made to be a metallic structure in which a proper amount of retained austenite remains by properly controlling the forming conditions, whereby the hot-stamped member having further improved ductility inherent in the formed product can be obtained. Patent document 2 discloses a hot-stamped steel having excellent ductility, which has a microstructure comprising, in mass%, 0.20 to 0.40% of C, 0.05 to 3.0% of Si, 1.0 to 4.0% of Mn, 0.05% or less of P, 0.05% or less of S, 0.005 to 0.1% of Al, 0.01% or less of N, and the balance being Fe and unavoidable impurities, and having an area ratio of 5 to 55% of ferrite phase, an area ratio of 45 to 95% of martensite phase, and an average particle diameter of 7 μm or less of ferrite phase and martensite phase in the whole structure. According to this technique, it is described that a hot-stamped member having a high strength of 1470 to 1750MPa in tensile strength and a high ductility of 8% or more in total elongation El can be obtained. In addition, with the increase in the strength of the member, there is a concern that the member will be damaged by hydrogen, that is, hydrogen embrittlement, and it is required to improve the delayed fracture resistance. In order to meet such a demand, for example, patent document 3 discloses a steel sheet for hot press forming, which is characterized in that spherical inclusions having a diameter of 0.1 μm or less, each containing two or more of S, O (oxygen) and REM, are dispersed in a stee