Fine-grained high-quality hot alloy steel,4Cr5MoSiV,high hardenability, high toughness, and fine-grained. Fine-grained high-quality hot alloy steel,4Cr5MoSiV,high hardenability, high toughness, and fine-grained. Smelting characteristics The ... appear secondary hardening peak. The peak value is around 55HRC with the worst toughness.Therefore, the tempering process should avoid around ...