Understanding the Composition and Heat Treatment of 420S45 Stainless Steel

[ad_1] 420S45 stainless steel is a martensitic stainless steel with a chemical composition of:

– Carbon (C): 0.36-0.42%
– Silicon (Si): max. 1%
– Manganese (Mn): max. 1%
– Phosphorus (P): max. 0.04%
– Sulfur (S): max. 0.03%
– Chromium (Cr): 12.0-14.0%

The high carbon content in 420S45 stainless steel makes it a hardenable steel with good strength and wear resistance. The addition of chromium provides good corrosion resistance.

The heat treatment process for 420S45 stainless steel involves:

1. Annealing: The steel is heated to a temperature of 745-825°C and then slowly cooled to relieve internal stresses and improve machinability.

2. Quenching: The steel is heated to 980-1065°C and then rapidly cooled (quenched) in oil or air to achieve maximum hardness.

3. Tempering: The quenched steel is then heated to a temperature between 150-370°C to reduce brittleness and increase toughness and ductility.

The mechanical properties of 420S45 stainless steel after heat treatment include:

– Hardness: 50-60 HRC (depending on the heat treatment process)
– Tensile strength: 700-1000 MPa
– Yield strength: 600-800 MPa
– Elongation: 12-18%
– Modulus of elasticity: 190-210 GPa

Overall, 420S45 stainless steel is commonly used in applications where high hardness, strength, and wear resistance are required, such as in surgical instruments, cutlery, industrial blades, and molds.