High-chromium heat-resistant steel
The present invention provides a high-chromium heat-resistant steel. The steel contains in mass %, C: 0.08% to 0.13%; Si: 0.15% to 0.45%; Mn: 0.1% to 1.0%; Ni: 0.01% to 0.5%; Cr: 10.0% to 11.5%; Mo: 0.3% to 0.6%; V: 0.10% to 0.25%; Nb: 0.01% to 0.06%; N: 0.015% to 0.07%; B: ≤0.005%, and Al: ≤0.04%. The balance consists of Fe and inevitable impurity elements. The steel shows a martensitic microstructure.
1. A high-chromium heat-resistant steel, consisting of, in mass %:
C: 0.08% to 0.13%;
Si: 0.15% to 0.45%;
Mn: 0.1% to 1.0%;
Ni: 0.01% to 0.5%;
Cr: 10.0% to 11.5%;
Mo: 0.3% to 0.6%;
V: 0.15% to 0.25%;
Nb: 0.01% to 0.06%;
N: 0.015% to 0.07%,
B: 0 to 0.005%; and
Al: 0 to 0.04%;
wherein the balance is Fe and inevitable impurity elements.
2. The high-chromium heat-resistant steel of claim 1 , wherein B is in the range of 0.001% to 0.005% by mass.
3. The high-chromium heat-resistant steel of claim 1 , wherein the mass % of the inevitable impurity elements is lower than 0.4%.
4. The high-chromium heat resistant steel of claim 1 , consisting of, in mass %:
C: 0.08% to 0.11%;
Si: 0.15% to 0.35%;
Mn: 0.40% to 0.60%;
Ni: 0.01% to 0.2%;
Cr: 10.45% to 11.0%;
Mo: 0.45% to 0.55%;
V: 0.15% to 0.25%;
Nb: 0.035% to 0.06%;
N: 0.040% to 0.070%;
B: 0 to 0.005%; and
Al: 0 to 0.04%;
wherein the balance is Fe and inevitable impurity elements.
5. The high-chromium heat-resistant steel of claim 4 , wherein B is in the range of 0.002% to 0.004%.
6. The high-chromium heat-resistant steel of claim 4 , wherein Al: 0 to 0.025% by mass.
7. A steam contacting component made from the high-chromium heat-resistant steel of claim 1 .
8. A pressure boiler comprising one or more steam contacting components made from the high-chromium heat-resistant steel of claim 1 .
9. A thermal power plant comprising the steam contacting component of claim 7 .
10. A thermal power plant comprising the pressure boiler of claim 8 .
11. The steam contacting component of claim 7 , wherein the steam contacting component is a tube.
12. The pressure boiler of claim 8 , wherein the one or more steam contacting components is a boiler drum.
13. The pressure boiler of claim 8 , wherein the one or more steam contacting components is a tube.
14. The high-chromium heat-resistant steel of claim 1 , wherein the steel has a martensitic microstructure.
15. The high-chromium heat-resistant steel of claim 14 , wherein the steel does not contain delta ferrite.
16. The high-chromium heat-resistant steel of claim 1 , wherein the steel has a creep rupture time of at least 21,985 hours under a temperature of 650° C. and a stress of 70 MPa.
17. The high-chromium heat-resistant steel of claim 1 , wherein the steel has a creep rupture time of at least 23,801 hours under a stress of 70 MPa at a temperature of 650° C.
18. The high-chromium heat-resistant steel of claim 1 , wherein the steel has a creep rupture time of at least 25,451 hours under a stress of 70 MPa at a temperature of 650° C.
19. The high-chromium heat-resistant steel of claim 1 , wherein the steel has a creep rupture time of between 21,985 and 25,451 hours under a stress of 70 MPa at a temperature of 650° C.
20. The high-chromium heat-resistant steel of claim 1 , wherein the steel forms an average scale thickness of at most 33 μm under a steam oxidation temperature of 650° C. for 1000 hours.
21. The high-chromium heat-resistant steel of claim 1 , wherein the steel forms an average scale thickness of at most 39 μm of under a steam oxidation temperature of 650° C. for 1000 hours.
22. The high-chromium heat-resistant steel of claim 1 , wherein the steel forms an average scale thickness of at most 40 μm under a steam oxidation temperature of 650° C. for 1000 hours.
23. The high-chromium heat-resistant steel of claim 1 , wherein the steel forms an average scale thickness of 33 to 40 μm under a steam oxidation temperature of 650° C. for 1000 hours.
24. The high-chromium heat-resistant steel of claim 1 , wherein the steel has a creep rupture time of between 21,985 and 25,451 hours under a stress of 70 MPa at a temperature of 650° C., and wherein the steel forms an average scale thickness of 33 to 40 μm under a steam oxidation temperature of 650° C. for 1000 hours.
25. The high-chromium heat-resistant steel of claim 1 , wherein Ni is in the range of 0.01% to 0.2% by mass.
26. The high-chromium heat-resistant steel of claim 1 , wherein Mo is in the range of 0.45% to 0.6% by mass.