此族群不銹鋼具有磁性，依據合金結構可分為兩種：麻田散不銹鋼與肥粒不銹鋼。
合金結構為麻田賽組織，所以被稱為麻田賽不銹鋼，進行熱處理可得優秀的強度與硬度，但耐蝕性較差，因此，在氯化物環境下，易生鏽與產生孔蝕情況。另一合金結構為肥粒組織，所以被稱為肥粒不銹鋼，並且無法進行熱處理使其硬化。但相較於麻田散不銹鋼，硬度較軟，但耐蝕性較佳。
400系列不銹鋼 化學成分表
| 鋼條種類 | 化學成份, wt% | |||||||||
| TYPE | C | Si | Mn | P | S | Ni | Cr | Mo | Cu | Free-cutting element |
| 416 | ≤0.15 | ≤1.0 | ≤1.25 | ≤0.060 | ≥0.015 | ≤0.60 | 12.00~14.00 | ≤0.60 | ||
| 420J2 | 0.26~0.40 | ≤1.0 | ≤1.0 | ≤0.040 | ≤0.030 | ≤0.60 | 12.00~14.00 | |||
| 420F | 0.26~0.40 | ≤1.0 | ≤1.25 | ≤0.060 | ≤0.15 | ≤0.60 | 12.00~14.00 | ≤0.60 | ||
| 430 | ≤0.15 | ≤0.75 | ≤1.00 | ≤0.040 | ≤0.030 | ≤0.60 | 16.00~18.00 | |||
| 430F | ≤0.12 | ≤1.0 | ≤1.25 | ≤0.060 | ≥0.15 | ≤0.60 | 16.00~18.00 | ≤0.60 | ||
| 440C | 0.95~1.20 | ≤1.0 | ≤1.25 | ≤0.030 | ≤0.030 | ≤0.60 | 16.00~18.00 | ≤0.75 | ||
| 416FC | ≤0.15 | ≤1.0 | ≤1.25 | ≤0.060 | >0.15 | — | 12.4 | — | Added | |
| DSR7 | 0.7 | ≤0.25 | ≤0.3 | ≤0.25 | — | — | <12 | Added | — | |
