Abrasion-resistant steel plate and method of producing abrasion-resistant steel plate

Patent metadata

Field	Value
Publication number	US-11111556-B2
Application number	US-201616092553-A
Country	US
Kind code	B2
Filing date	Apr 19, 2016
Priority date	Apr 19, 2016
Publication date	Sep 7, 2021
Grant date	Sep 7, 2021

Abstract

An abrasion-resistant steel plate comprises: a specific chemical composition; and a microstructure in which a volume fraction of martensite at a depth of 1 mm from a surface of the abrasion-resistant steel plate is 90% or more, and a prior austenite grain size in a plate thickness central part at the mid-thickness of the abrasion-resistant steel plate is 80 μm or less, wherein hardness at a depth of 1 mm from the surface of the abrasion-resistant steel plate is 460 to 590 HBW 10/3000 in Brinell hardness, and a concentration [Mn] of Mn in mass % and a concentration [P] of P in mass % in a plate thickness central segregation area satisfy 0.04[Mn]+[P]<0.50.

First claim

The invention claimed is:

1. An abrasion-resistant steel plate comprising:
a chemical composition containing, in mass %,
C: more than 0.23% and 0.34% or less,
Si: 0.01% to 1.0%,
Mn: 0.30% to 2.50%,
P: 0.020% or less,
S: 0.01% or less,
Cr: 0.01% to 2.00%,
Al: 0.001% to 0.100%,
N: 0.01% or less, and
a balance consisting of Fe and inevitable impurities; and

a microstructure in which a volume fraction of martensite at a depth of 1 mm from a surface of the abrasion-resistant steel plate is 90% or more, and a prior austenite grain size at the mid-thickness of the abrasion-resistant steel plate is 80 μm or less,
wherein hardness at a depth of 1 mm from the surface of the abrasion-resistant steel plate is 460 to 590 HBW 10/3000 in Brinell hardness, and
a concentration [Mn] of Mn in mass % and a concentration [P] of P in mass % in a plate thickness central segregation area satisfy the following Expression (1):
0.04[Mn]+[P]<0.50  (1).

2. The abrasion-resistant steel plate according to claim 1 ,
wherein the chemical composition further contains, in mass %, one or more elements selected from the group consisting of
Cu: 0.01% to 2.0%,
Ni: 0.01% to 5.0%,
Mo: 0.01% to 3.0%,
Nb: 0.001% to 0.100%,
Ti: 0.001% to 0.050%,
B: 0.0001% to 0.0100%,
V: 0.001% to 1.00%,
W: 0.01% to 1.5%,
Ca: 0.0001% to 0.0200%,
Mg: 0.0001% to 0.0200%, and
REM: 0.0005% to 0.0500%.

3. The abrasion-resistant steel plate according to claim 1 ,
wherein a reduction of area in a tensile test of the abrasion-resistant steel plate after subjecting the abrasion-resistant steel plate to temper embrittlement treatment and subsequent hydrogen embrittlement treatment is 10% or more.

4. The abrasion-resistant steel plate according to claim 2 ,
wherein a reduction of area in a tensile test of the abrasion-resistant steel plate after subjecting the abrasion-resistant steel plate to temper embrittlement treatment and subsequent hydrogen embrittlement treatment is 10% or more.

5. A method of producing the abrasion-resistant steel plate according to claim 1 , the method comprising:
subjecting molten steel to continuous casting, to form a slab;
heating the slab to 1000° C. to 1300° C.;
subjecting the heated slab to hot rolling in which reduction rolling with a rolling shape factor of 0.7 or more and a rolling reduction of 7% or more at a plate thickness central part temperature of 950° C. or more is performed three times or more, to obtain a hot-rolled steel plate;
reheating the hot-rolled steel plate to a reheating quenching temperature; and
quenching the reheated hot-rolled steel plate,
wherein the slab has the chemical composition according to claim 1 ,
in the continuous casting, light reduction rolling with a rolling reduction gradient of 0.4 mm/m or more is performed twice or more, upstream from a final solidification position of the slab,
the reheating quenching temperature is Ac 3 to 1050° C., and
an average cooling rate from 650° C. to 300° C. in the quenching is 1° C./s or more.

6. A method of producing the abrasion-resistant steel plate according to claim 2 , the method comprising:
subjecting molten steel to continuous casting, to form a slab;
heating the slab to 1000° C. to 1300° C.;
subjecting the heated slab to hot rolling in which reduction rolling with a rolling shape factor of 0.7 or more and a rolling reduction of 7% or more at a plate thickness central part temperature of 950° C. or more is performed three times or more, to obtain a hot-rolled steel plate;
reheating the hot-rolled steel plate to a reheating quenching temperature; and
quenching the reheated hot-rolled steel plate,
wherein the slab has the chemical composition according to claim 2 ,
in the continuous casting, light reduction rolling with a rolling reduction gradient of 0.4 mm/m or more is performed twice or more, upstream from a final solidification position of the slab,
the reheating quenching temperature is Ac 3 to 1050° C., and
an average cooling rate from 650° C. to 300° C. in the quenching is 1° C./s or more.

7. The method according to claim 5 , further comprising
tempering the quenched hot-rolled steel plate at a tempering temperature of 100° C. to 300° C.

8. The method according to claim 6 , further comprising
tempering the quenched hot-rolled steel plate at a tempering temperature of 100° C. to 300° C.

9. A method of producing the abrasion-resistant steel plate according to claim 1 , the method comprising:
subjecting molten steel to continuous casting, to form a slab;
heating the slab to 1000° C. to 1300° C.;
subjecting the heated slab to hot rolling in which reduction rolling with a rolling shape factor of 0.7 or more and a rolling reduction of 7% or more at a plate thickness central part temperature of 950° C. or more is performed three times or more, to obtain a hot-rolled steel plate; and
direct quenching the hot-rolled steel plate,
wherein the slab has the chemical composition according to claim 1 ,
in the continuous casting, light reduction rolling with a rolling reduction gradient of 0.4 mm/m or more is performed twice or more, upstream from a final solidification position of the slab,
a direct quenching temperature in the direct quenching is Ac 3 or more, and
an average cooling rate from 650° C. to 300° C. in the direct quenching is 1° C./s or more.

10. A method of producing the abrasion-resistant steel plate according to claim 2 , the method comprising:
subjecting molten steel to continuous casting, to form a slab;
heating the slab to 1000° C. to 1300° C.;
subjecting the heated slab to hot rolling in which reduction rolling with a rolling shape factor of 0.7 or more and a rolling reduction of 7% or more at a plate thickness central part temperature of 950° C. or more is performed three times or more, to obtain a hot-rolled steel plate; and
direct quenching the hot-rolled steel plate,
wherein the slab has the chemical composition according to claim 2 ,
in the continuous casting, light reduction rolling with a rolling reduction gradient of 0.4 mm/m or more is performed twice or more, upstream from a final solidification position of the slab,
a direct quenching temperature in the direct quenching is Ac 3 or more, and
an average cooling rate from 650° C. to 300° C. in the direct quenching is 1° C./s or more.

11. The method according to claim 9 , further comprising
tempering the quenched hot-rolled steel plate at a tempering temperature of 100° C. to 300° C.

12. The method according to claim 10 , further comprising
tempering the quenched hot-rolled steel plate at a tempering temperature of 100° C. to 300° C.

13. The abrasion-resistant steel plate according to claim 1 ,
wherein the prior austenite grain size at the mid-thickness of the abrasion-resistant steel plate is 13 μm or more and 80 μm or less.

Assignees

• Jfe Steel Corp

Inventors

• Terazawa Yusuke
• Takayama Naoki
• Hayashi Kenji
• Hase Kazukuni

Classifications

• C21D8/02

  during manufacturing of plates or strips (C21D8/12 takes precedence) · CPC title

• B22D11/1206

  for plastic shaping of strands (rolling mills B21B1/46) · CPC title

• C22C38/40

  with nickel · CPC title

• C22C38/28

  with titanium or zirconium · CPC title

• C22C38/38 Primary

  with more than 1.5% by weight of manganese · CPC title