Steel with excellent rolling-contact fatigue properties

Patent metadata

Field	Value
Publication number	US-9303302-B2
Application number	US-201114118370-A
Country	US
Kind code	B2
Filing date	May 25, 2011
Priority date	May 25, 2011
Publication date	Apr 5, 2016
Grant date	Apr 5, 2016

Abstract

Disclosed is a steel having high manufacturability and better rolling-contact fatigue properties. The steel contains C of 0.65% to 1.30%, Si of 0.05% to 1.00%, Mn of 0.1% to 2.00%, P of greater than 0% to 0.050%, S of greater than 0% to 0.050%, Cr of 0.15% to 2.00%, Al of 0.010% to 0.100%, N of greater than 0% to 0.025%, Ti of greater than 0% to 0.015%, and O of greater than 0% to 0.0025% and further contains iron and unavoidable impurities. Al-containing nitrogen compound particles dispersed in the steel have an average equivalent circle diameter of 25 to 200 nm, and Al-containing nitrogen compound particles each having an equivalent circle diameter of 25 to 200 nm are present in a number density of 1.1 to 6.0 per square micrometer.

First claim

The invention claimed is:

1. A steel, comprising:
C in a content of from 0.65% to 1.30%;
Si in a content of from 0.05% to 1.00%;
Mn in a content of from 0.1% to 2.00%;
P in a content of from greater than 0% to 0.050%;
S in a content of from greater than 0% to 0.050%;
Cr in a content of from 0.15% to 2.00%;
Al in a content of from 0.010% to 0.042%;
N in a content of from greater than 0% to 0.025%;
Ti in a content of from greater than 0% to 0.015%; and
O in a content of from greater than 0% to 0.0025%,

in mass percent, with the balance consisting of iron and inevitable impurities,
wherein Al-containing nitrogen compound particles dispersed in the steel have an average equivalent circle diameter of from 25 to 200 nm, and
wherein Al-containing nitrogen compound particles each having an equivalent circle diameter of from 25 to 200 nm are present in a number density of from 1.1 to 6.0 per square micrometer.

2. The steel of claim 1 , wherein the steel has an average prior austenitic grain size number of 11.5 or less.

3. The steel of claim 1 , further comprising at least one element selected from the group consisting of:
Cu in a content of from greater than 0% to 0.25%;
Ni in a content of from greater than 0% to 0.25%; and
Mo in a content of from greater than 0% to 0.25%.

4. The steel of claim 1 , further comprising at least one element selected from the group consisting of:
Nb in a content of from greater than 0% to 0.5%;
V in a content of from greater than 0% to 0.5%; and
B in a content of from greater than 0% to 0.005%.

5. The steel of claim 1 , further comprising at least one element selected from the group consisting of:
Ca in a content of from greater than 0% to 0.05%;
REM or REMs in a content of from greater than 0% to 0.05%;
Mg in a content of from greater than 0% to 0.02%;
Li in a content of from greater than 0% to 0.02%; and
Zr in a content of from greater than 0% to 0.2%.

6. The steel of claim 1 , further comprising at least one element selected from the group consisting of:
Pb in a content of from greater than 0% to 0.5%;
Bi in a content of from greater than 0% to 0.5%; and
Te in a content of from greater than 0% to 0.1%.

7. The steel of claim 1 , comprising C in a content of from 0.95% to 1.30%.

8. The steel of claim 1 , comprising Ti in a content of from greater than 0% to 0.0035%.

9. The steel of claim 1 , comprising:
C in a content of from 0.95% to 1.30%; and
Ti in a content of from greater than 0% to 0.0035%.

Assignees

• Kaizuka Masaki
• Kobe Steel Ltd

Inventors

• Kaizuka Masaki

Classifications

• C21D9/40 Primary

  for rings; for bearing races · CPC title

• C22C38/001 Primary

  containing N · CPC title

• C22C38/24

  with vanadium · CPC title

• C22C38/22

  with molybdenum or tungsten · CPC title

• C22C38/38

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