按化学成分分类不锈钢有Cr不锈钢和Cr、Ni不锈钢两大类。影响不锈钢腐蚀性能的主要是含C量和析出的碳化物，所以耐腐蚀不锈钢含C量越低越好，通常C≤0.08%,但是，耐热钢的高温力学性能则决定于其组织中稳定的碳化物沉淀相，所以耐热钢的含C量都较高，一般含碳量在0.20%以上。
According to the classification of chemical composition, stainless steel includes CR stainless steel and Cr and Ni stainless steel. The corrosion performance of stainless steel is mainly affected by the C content and precipitated carbides. Therefore, the lower the C content of corrosion-resistant stainless steel, the better, usually C ≤ 0.08%. However, the high-temperature mechanical properties of heat-resistant steel depend on the stable carbide precipitation phase in its structure. Therefore, the C content of heat-resistant steel is high, generally more than 0.20%.
按金相组织分类，不锈钢分为铁素体不锈钢、马氏体不锈钢、奥氏体不锈钢和双相（在奥氏体基体中有铁素体）不锈钢
According to the classification of metallographic structure, stainless steel is divided into ferritic stainless steel, martensitic stainless steel, austenitic stainless steel and duplex (ferritic in austenitic matrix) stainless steel