High-hardness low-alloy wear-resistant steel sheet and method of manufacturing the same

Patent metadata

Field	Value
Publication number	US-10208369-B2
Application number	US-201414649684-A
Country	US
Kind code	B2
Filing date	Mar 19, 2014
Priority date	Mar 28, 2013
Publication date	Feb 19, 2019
Grant date	Feb 19, 2019

Abstract

A high-hardness low-alloy wear-resistant steel sheet and a method of manufacturing the same, which has the chemical compositions (wt %): C: 0.33-0.45%; Si: 0.10-0.50%; Mn: 0.50-1.50%; B: 0.0005-0.0040%; Cr: less than or equal to 1.50%; Mo: less than or equal to 0.80%; Ni: less than or equal to 2.00%; Nb: less than or equal to 0.080%; V: less than or equal to 0.080%; Ti: less than or equal to 0.060%; RE: less than or equal to 0.10%; W: less than or equal to 1.00%; Al: 0.010-0.080%, Ca: 0.0010-0.0080%, N: less than or equal to 0.0080%, O: less than or equal to 0.0080%, H: less than or equal to 0.0004%, P: less than or equal to 0.015%, S: less than or equal to 0.010%, and (Cr/5+Mn/6+50B): more than or equal to 0.20% and less than or equal to 0.50%; (Mo/3+Ni/5+2Nb): more than or equal to 0.02% and less than or equal to 0.50%; (Al+Ti): more than or equal to 0.01% and less than or equal to 0.13%, the remainders being Fe and unavoidable impurities. The steel sheet obtained from the above-mentioned chemical compositions and processes, has high hardness, excellent wear-resistant performance, and is applicable to a variety of parts in mechanical equipments extremely vulnerable to wearing.

First claim

What is claimed is:

1. A wear-resistant steel sheet consisting of:
a) greater than 0.33% to less than or equal to 0.37 wt % carbon (C):
b) 0.33-0.50 wt % silicon (Si);
c) 0.95-1.50 wt % manganese (Mn);
d) 0.0005-0.0040 wt % boron (B);
e) less than or equal to 1.50 wt % chromium (Cr);
f) 0.17-0.80 wt % molybdenum (Mo);
g) 0.31-2.00 wt % nickel (Ni);
h) greater than 0% to less than or equal to 0.080 wt % niobium (Nb);
i) greater than 0% to less than or equal to 0.080 wt % vanadium (V);
j) less than or equal to 0.060 wt % titanium (Ti);
k) less than or equal to 0.10 wt % rare earth (RE);
l) greater than 0% to less than or equal to 1.00 wt % tungsten (W);
m) 0.010-0.080 wt % aluminum (Al);
n) 0.0010-0.0080 wt % calcium (Ca);
o) less than or equal to 0.0080 wt % nitrogen (N);
p) less than or equal to 0.0080 wt % oxygen (O);
q) less than or equal to 0.0004 wt % hydrogen (H);
r) less than or equal to 0.015 wt % phosphorus (P);
s) less than or equal to 0.010 wt % sulfur (S);
t) 0.20-0.50 wt % (Cr/5+Mn/6+50B)
u) 0.02-0.50 wt % (Mo/3+Ni/5+2Nb)
v) 0.01-0.13 wt%(Al+Ti)
w) a remainder of iron (Fe) and other unavoidable impurities;
wherein the steel sheet comprises microstructures of martensite and retained austenite, a hardness of equal to or more than 575 HB, and a Charpy V-notch longitudinal impact energy of equal to or more than 65 J as measured at −40° C.

2. The steel sheet according to claim 1 , wherein carbon: 0.35-0.37 wt %; and silicon: 0.33-0.40 wt %.

3. The steel sheet according to claim 1 , wherein manganese: 0.95-1.20 wt %; chromium: 0.10-1.30 wt %; molybdenum: 0.17-0.60 wt %; nickel: 0.31-1.50 wt %; and (Mo/3+Ni/5+2Nb): between 0.04-0.45 wt %.

4. The steel sheet according to claim 1 , wherein niobium: 0.005-0.080 wt %; vanadium: less than or equal to 0.060 wt %; rare earth: less than or equal to 0.080 wt %; and tungsten: less than or equal to 0.80 wt %.

5. The steel sheet according to claim 1 , wherein boron: 0.0005-0.0020 wt %; calcium: 0.0010%-0.0060 wt %; and (Cr/5+Mn/6+50B) between 0.20-0.45 wt %.

6. The steel sheet according to claim 1 , wherein nitrogen: less than or equal to 0.0050 wt %; oxygen: less than or equal to 0.0050 wt %; hydrogen: less than or equal to 0.0003 wt %; phosphorus: less than or equal to 0.012 wt %; and sulfur: less than or equal to 0.005 wt %.

7. The steel sheet of claim 1 , wherein aluminum: 0.020-0.080 wt %; titanium: 0.005-0.060 wt %; and (Al+Ti): between 0.01-0.12 wt %.

8. A method of manufacturing the wear-resistant steel sheet according to claim 1 , the method comprising:
a) smelting the elements of claim 1 to yield a smelted material;
b) casting the smelted material;
c) heating the casted material to a slab heating temperature of 1000-1200° C. for a heat preservation time ranging from 1-3 hours;
d) rolling the heated material at a rough rolling temperature of 900-1150° C. and a finish rolling temperature is 780-880° C.; and
e) cooling the rolled material directly after rolling by water cooling the material to below 400° C. at a speed greater than or equal to 20° C./s, then air cooling the material to ambient temperature to obtain the wear-resistant steel sheet; wherein the resultant steel sheet comprises microstructures of martensite and retained austenite, wherein the volume fraction of the retained austenite is less than or equal to 5%;
wherein the wear-resistant steel sheet according to claim 1 is produced and the resultant steel sheet exhibits a hardness of more than 575 HB, and a Charpy V-notch longitudinal impact energy of more than 65 J as measured at −40° C.

9. The method of claim 8 , further comprising tempering the cooled material at a heating temperature of 100-400° C. for a heat preservation time of 30-120 min.

10. The method of claim 8 , wherein the slab heating temperature is 1000-1150° C.

11. The method of claim 8 , wherein the rough rolling temperature is 900-1100° C., and the reduction rate during rough rolling is more than 20%; and
wherein the finish rolling temperature is 780-860° C., and the reduction rate during finish rolling is more than 40%.

12. The method of claim 8 , wherein the water cooling temperature is below 380° C., and the water cooling speed is greater than or equal to 23° C./s.

13. The method of claim 9 , wherein the tempering temperature is 100-380° C., and the heat preservation time is 30-100 min.

Assignees

• Baoshan Iron & Steel

Inventors

• Li Hongbin
• Yao Liandeng
• Song Guobin

Classifications

• C21D6/008

  containing Si · CPC title

• C21D8/0226

  Hot rolling · CPC title

• C22C38/04

  containing manganese · CPC title

• C21D9/46

  for sheet metals · CPC title

• C22C38/44

  with molybdenum or tungsten · CPC title