N31 30CrMnSiNi2A D406A 30Si2MnCrMoVE 31Si2MnCrMoVE 面议 4340 40CrNi2MoA 300M 40CrNi2Si2MoVA 42CrNi2Si2MoVA 面议 D6AC 45CrNiMo1VA 45CrNiMoVA 40CrNiMoA 20Cr2Ni4A 面议 15CrMn 20CrMn 40CrMn 55CrMnA 60CrMnA 35CrMo 30CrMo 面议 304 310S 316L 317L 321 2205 2507 9Cr18 9Cr18Mo 不锈钢 面议 20CrMo 25CrMo 30CrMo 35CrMo 42Crmo 50Crmo 27SiMn 面议