Both ferritic stainless steels and martensitic stainless steels are regarded as 400 series of stainless steels and classified by phase constituent of microstructure. Ferritic stainless steels are soft and tough; on the other hands, martensitic stainless steels are hard, strong, but brittle.
   Both of their resistance to rusting are worse than austenitic stainless steels. Furthermore, ferritic stainless steels are unable to be hardened by heat treated; however, martensitic stainless steels are heat treatable to obtain the premium hardness and strength.

Stainless Steels Chemical Composition, %
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 —