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 ... .According to the use of molds, the tempering temperature should be in the range of 540-620 Fine-grained high-quality hot alloy steel ...