# US 12,180,572 B2 · Wear-resistant steel plate and method for producing same > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,180,572 B2 - Document ID: US12180572B2 - Status: Granted - Kind: B2 - Application number: 17/753,552 - Filed: 2020-08-17 - Published: 2022-10-20 - Granted: 2024-12-31 - Earliest claimed: 2019-09-17 - Assignees: Jfe Steel Corporation - Applicants: Jfe Steel Corporation - Inventors: Naoki Takayama; Shigeki Kitsuya; Yoshiaki Murakami - Web page: https://patentgrep.com/patent/US12180572B2 ## CPC - C21D 6/002: {containing Cr (C21D6/004 takes precedence)} - C22C 38/38: with more than 1.5% by weight of manganese - C21D 1/02: Hardening articles or materials formed by forging or rolling, with no further heating beyond that required for the formation - C21D 1/18: Hardening (C21D1/02 takes precedence); Quenching with or without subsequent tempering (quenching devices C21D1/62) - C21D 1/19: by interrupted quenching - C21D 6/005: {containing Mn} - C21D 6/02: Hardening by precipitation - C21D 8/02: during manufacturing of plates or strips (C21D8/12 takes precedence) - C21D 8/021: involving particular fabrication steps or treatments of ingots or slabs - C21D 8/0226: {Hot rolling} - C21D 8/0263: {following hot rolling} - C21D 8/04: to produce plates or strips for drawing, e.g. for deep-drawing - C21D 8/0426: {Hot rolling} - C21D 9/46: for sheet metals - C22C 38/001: {containing N} - C22C 38/002: {containing In, Mg, or other elements not provided for in one single group C22C38/001 - C22C38/60} - C22C 38/005: {containing rare earths, i.e. Sc, Y, Lanthanides} - C22C 38/02: containing silicon - C22C 38/04: containing manganese - C22C 38/06: containing aluminium - C22C 38/18: containing chromium - C22C 38/20: with copper - C22C 38/22: with molybdenum or tungsten - C22C 38/24: with vanadium - C22C 38/26: with niobium or tantalum - C22C 38/28: with titanium or zirconium - C22C 38/30: with cobalt - C22C 38/32: with boron - C22C 38/40: with nickel - C22C 38/60: containing lead, selenium, tellurium, or antimony, or more than 0.04% by weight of sulfur - C21D 2211/008: Martensite - 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 (surface treatment of metallic material involving at least one process provided for in class C23 and at least one process covered by this subclass C23F17/00; unidirectional solidification of eutectic materials or unidirectional demixing of eutectoid materials C30B) - C22C: ALLOYS (treatment of alloys C21D, C22F) ## Abstract The steel plate has a specific chemical composition, and a microstructure where a volume fraction of martensite at a depth of 1 mm from a surface of the steel plate is 95% or more, and at a depth of 1 mm from a surface of the steel plate, a Vickers hardness at 400° C. is 288 or more, and a Brinell hardness at 25° C. is 360 HBW10/3000 to 490 HBW10/3000. ## Claims ### Claim 1 A wear-resistant steel plate, comprising a chemical composition containing, in mass %, C: 0.10% or more and 0.23% or less, Si: 0.05% or more and 1.00% or less, Mn: 0.10% or more and 2.00% or less, P: 0.050% or less, S: 0.050% or less, Al: 0.050% or less, Cr: 1.00% or more and 5.00% or less, N: 0.0100% or less, and O: 0.0100% or less, with the balance being Fe and inevitable impurities, wherein the chemical composition satisfies the formula (1) 1.00≤0.45Cr+Mo≤2.25 (1), where the element symbol in the formula (1) is a content of each element in mass %, and a content of an element that is not contained is 0, and a microstructure wherein a volume fraction of martensite at a depth of 1 mm from a surface of the steel plate is 95% or more, and at a depth of 1 mm from a surface of the steel plate, a Vickers hardness at 400° C. is 288 or more, and a Brinell hardness at 25° C. is 360 HBW10/3000 to 490 HBW10/3000. ### Claim 2 (depends on 1) The wear-resistant steel plate according to claim 1, wherein the chemical composition further contains, in mass %, at least one selected from the group consisting of Mo: 1.80% or less, Cu: 5.00% or less, Ni: 5.00% or less, V: 1.00% or less, W: 1.00% or less, Co: 1.00% or less, Nb: 0.050% or less, Ti: 0.100% or less, B: 0.0100% or less, Ca: 0.0200% or less, Mg: 0.0200% or less, and REM: 0.0200% or less. ### Claim 3 (depends on 1) A method for producing a wear-resistant steel plate, which is a method for producing the wear-resistant steel plate according to claim 1, comprising subjecting a steel material to hot rolling to obtain a hot-rolled steel plate, and subjecting the hot-rolled steel plate to direct quenching where a cooling start temperature is equal to or higher than Ar3 transformation point, a cooling stop temperature is equal to or lower than Ms point, and a cooling rate is 5° C./s or higher, or to reheating quenching where a cooling start temperature is equal to or higher than Ac3 transformation point, a cooling stop temperature is equal to or lower than Mf point, and a cooling rate is 5° C./s or higher. ### Claim 4 (depends on 2) A method for producing a wear-resistant steel plate, which is a method for producing the wear-resistant steel plate according to claim 2, comprising subjecting a steel material to hot rolling to obtain a hot-rolled steel plate, and subjecting the hot-rolled steel plate to direct quenching where a cooling start temperature is equal to or higher than Ar3 transformation point, a cooling stop temperature is equal to or lower than Ms point, and a cooling rate is 5° C./s or higher, or to reheating quenching where a cooling start temperature is equal to or higher than Ac3 transformation point, a cooling stop temperature is equal to or lower than Mf point, and a cooling rate is 5° C./s or higher.