Steel for small-caliber weapon
The present invention relates to a steel composition, to the process for manufacturing same, to the steel blank obtained having a hardness of between 46 and 48 HRC and a resilience KV at −40° C. of at least 40 joules, and to the use thereof for manufacturing a pressure appliance component.
1. A steel composition consisting essentially of:
carbon: 0.28-0.35;
manganese: 0.10-0.60;
silicon: 0.10-0.20;
chromium: 2.80-3.40;
molybdenum: 0.70-1.60;
Vanadium: 0.20-0.50;
phosphorus: ≤0.005;
nickel: ≤0.10;
aluminium: ≤0.025;
copper: ≤0.10;
arsenic+antimony+tin: <100 ppm;
sulfur: <10 ppm;
iron: remainder;
as weight percentages of the total composition, and also inevitable impurities, wherein the steel composition when heat treated has a resilience KV at −40° C. of at least 40 joules.
2. The steel composition according to claim 1 , consisting essentially of:
carbon: 0.28-0.35;
manganese: 0.10-0.20;
silicon: 0.10-0.20;
chromium: 2.80-3.40;
molybdenum: 0.70-1.30;
vanadium: 0.20-0.40;
phosphorus: ≤0.005;
nickel: ≤0.10;
aluminium: ≤0.025;
copper: ≤0.10;
arsenic+antimony+tin: <100 ppm;
sulfur: <10 ppm;
iron: remainder;
as weight percentages of the total composition, and also the inevitable impurities.
3. The steel composition according to claim 1 , wherein the molybdenum content is between 0.7 and 1.1, as weight percentages of the total composition.
4. The steel composition according to claim 1 , wherein the aluminium content is between 0.006 and 0.025, as a weight percentage of the total composition.
5. A pressure appliance component made from the steel composition according to claim 1 .
6. The pressure appliance component according to claim 5 , wherein the pressure appliance component is a barrel tube.
7. The pressure appliance component according to claim 6 , wherein the barrel tube is for a small-calibre weapon.
8. A steel blank formed from the steel composition of claim 1 , wherein the steel blank has the resilience KV at −40° C. of at least 40 joules.
9. The steel blank according to claim 8 , wherein the steel blank has a mechanical strength Rm of between 1500 and 1600 MPa.
10. The steel blank according to claim 8 , wherein the steel blank has a hardness at or between 46 and 48 HRC.
11. A process for manufacturing a steel blank having the composition according to claim 1 , the process comprising:
a) a step of producing the steel;
b) a step of transforming the steel;
c) a heat treatment of the steel comprising a tempering treatment at a temperature of at least 530° C., for an overall time of between 2 and 6 hours.
12. The process according to claim 11 , wherein step c) comprises several tempering treatments, the cumulative times of which correspond to the overall time of said step.
13. The process according to claim 12 , wherein step c) comprises two tempering treatments of 2 hours each.
14. The process according to claim 11 , wherein step c) comprises, before the tempering treatment, quenching at a temperature of at least 900° C.
15. The process according to claim 14 , wherein the quenching is at a temperature of between 900 and 930° C.
16. The process according to claim 11 , wherein step b) consists of a rolling step.
17. The process according to claim 11 , wherein the production step a) is performed in an electric arc furnace followed by vacuum arc degassing, or via VIM-VAR or VIM-ESR processes.
18. The process according to claim 17 , wherein the production step a) is performed in an electric arc furnace followed by vacuum arc degassing with a step of electroslag remelting (ESR) or vacuum arc remelting (VAR).
19. The process according to claim 11 , wherein the tempering treatment of step c) is at a temperature of between 530 and 550° C. for an overall time of 4 hours.