4330V

[arash66]

thread330-193037
Hi, can anyone please tell me why 4330V is immune to temper embrittlement?

 

[TVP]

Because of the following:

1. It is alloyed with 0.35-0.50% Mo, which is more effective than the usual 0.20-0.30% addition specified in SAE J404, ASTM A29, etc.
2. It is processed to a fine grain practice (austenite grain size finer than ASTM #5).
3. The Mo and V additions allow for higher initial tempering temperatures to be used, which greatly reduces/eliminates the formation of cementite films on prior austenite grain boundaries. Cementite films reduce the fracture toughness, and promote embrittlement by P and other impurity elements.

 

[arash66]

thank you very much