NSSC 550(13Cr-2Ni-2Mo)是新日铁住金独自开发的兼具高硬度和高耐蚀性的马氏体(M)系不锈钢商品。将此钢进行适当淬火和回火处理，可以获得0.2%屈服强度1150N/mm2、抗拉强度1750N/mm2、HV(维氏强度)550的极高强度和硬度，且具有与SUS304钢同等以上的耐蚀性，加之作为线材制品也具备重要的锻压性，故被用作建材中的自动攻丝螺栓、各种高强度销钉和高强度链条等。
High Strength high Rust-Resistant Ferritic Stainless Steel
NSSC 550 is a martensitic grade with remarkably improved quench hardening.
Superior to SUS 304 in corrosion resistance by appropriate addition of Cr and Mo, as well as by control of trace elements.
Superior to SUS 304 in its performance of wire drawings as well as cold-heading.
Applications: Self-tapping screws, High-strength nails, Various kinds of pins, High-strength chains and other applications requiring high hardness and high rust resistance.