Martensitic stainless steel for injection moulds and injection mould frames

1. Mold component or mold frame component for the injection-molding of plastics materials, which component is composed of quenched and tempered martensitic stainless steel whose composition consists of, in % by weight:

0.02%≦C≦0.09%

0.025%≦N≦0.12%

with 0.05%≦C+N≦0.14%

Si<0.17%

Al≦0.080%

with Si+23 Al≧0.20%

and Si+0.6 Al≦0.17%

and 0.00025≦Al×N≦0.0020

1.05<Mn≦1.8%

11.5%≦Cr≦16%

0<Ti≦0.020%

0.05%≦5<0.25%

optionally up to 0.48% of copper, up to 0.90% of the sum Mo+W/2, up to 0.48% of nickel, up to 0.090% of vanadium, and up to 0.090% of niobium,

the balance being iron and impurities resulting from the production operation, the composition also satisfying the condition:

6.5≦F═(Cr+Mo)+2(Si+V+Nb)−27(C+N)−(Ni+Mn/2+Cu/3)≦13.

2. Component according to claim 1 , wherein: Cu≦0.4%.

3. Component according to claim 1 or claim 2 , wherein: Al×N≧0.00050.

4. Component according to claim 1 or 2 , wherein the composition satisfies at least one of the following conditions:

Ni≧0.10%

V≧0.015%

Mo+W/2≧0.10%.

5. Component according to claim 1 or 2 , wherein the composition satisfies the condition: 7.0≦F≦8.9.

6. Component according to claim 1 or 2 , wherein the composition satisfies the condition: 9.0≦F≦11.5.

7. Component according to claim 1 or 2 , wherein: Nb<0.020%.

8. Component according to claim 1 or 2 , wherein the structure of the steel contains less than 20% of δ ferrite, the balance being martensite.

9. Component according to claim 8 , wherein the structure of the steel contains less than 10% of δ ferrite, the balance being martensite.