Stainless Steel (UNS S43100, 1.4057)

Key Characteristics

Type: Martensitic Stainless Steel (UNS S43100, 1.4057).

Composition: Contains ~15-18% Chromium, 1.25-3% Nickel, and controlled Carbon, balancing corrosion resistance with hardness.

Heat Treatable: Achieves high hardness (around 40 HRC) and strength through hardening and tempering.

Corrosion Resistance: Best among conventional martensitic grades, superior to 410/430, suitable for marine and petroleum exposure.

Strength: Offers high yield and tensile strength, good toughness.

Advantages

Superior strength and toughness compared to other martensitic steels.

Excellent corrosion resistance for its class.

Cost-effective for high-strength needs compared to some advanced grades.

Limitations

Poor weldability compared to austenitic grades.

Not recommended for severe cold forming (bending, deep drawing) due to high yield strength.

Reduced impact toughness at sub-zero temperatures.

Common Applications

Aerospace fittings and fasteners.

Bolts, nuts, and high-stress shafts.

Pump shafts and marine hardware.

Automotive components.

Fabrication Notes

Usually supplied hardened and tempered (Condition T).

Heat treatment involves quenching (980-1065°C) and tempering (avoiding 425-600°C) for optimal properties.