SUS410 vs SUS420: Martensitic Steel Strength Comparison

SUS420: Higher carbon content allows it to achieve superior hardness (e.g., 50-55 HRC in hardened state) and wear resistance, making it excellent for blades and surgical tools.

SUS410: Moderate carbon content provides good strength but less hardness than 420, balancing strength with toughness and better flexibility.

420 has significantly more carbon, driving its hardness; 410 has lower carbon for general-purpose use.

Hardness vs. Toughness: 420 excels in hardness; 410 offers better toughness and flexibility.

420: Knives, surgical instruments, cutting tools, precision parts (needs high hardness).

410: Fasteners, structural components, gears, general industrial parts (needs balance of properties).

Both offer moderate resistance (chromium content), but 420's higher hardness also improves wear resistance.

SUS420 for applications demanding maximum hardness, edge retention, and wear resistance, despite higher cost. Choose SUS410 for cost-effective, all-around performance where moderate strength, good machinability, and toughness are required.