SUS420J2 Stainless steel introduction
SUS420J2 is a martensitic stainless steel with high hardness, wear resistance and corrosion resistance. Due to its high carbon content (0.26-0.40%), high hardness and strength can be obtained after proper heat treatment, which is often used in the manufacture of tools, surgical instruments, molds and other parts requiring high hardness and wear resistance.

Chemical composition of SUS420J2 Stainless Steel Strip(typical value) :

• Carbon (C) : 0.26-0.40%
• Silicon (Si) : ≤1.00%
• Manganese (Mn) : ≤1.00%
• Phosphorus (P) : ≤0.040%
• Sulfur (S) : ≤0.030%
• Chromium (Cr) : 12.0-14.0%

Mechanical properties of SUS420J2 Stainless Steel Strip (after heat treatment) :

• Tensile strength: ≥635 MPa
• Yield strength: ≥440 MPa
• Elongation: ≥15%
• Hardness: ≥50 HRC (after quenching and tempering)

Physical properties of SUS420J2 Stainless Steel Strip:

• Density: 7.75 g/cm³
• Melting point: 1450-1510℃
• Thermal expansion coefficient: 10.5μm /m·℃ (20-100℃)
• Thermal conductivity: 24.9W /m·K (100℃)

Heat treatment process
The heat treatment of SUS420J2 stainless steel is crucial to its performance, and common heat treatment processes include:

Annealing:

• Temperature: 800-900℃
• Cooling method: furnace cooling or air cooling
• Objective: To soften the material and facilitate processing.

Quenching:

• Temperature: 980-1050℃
• Cooling method: oil cooling or air cooling
• Objective: To improve the hardness and strength.

Temper:

• Temperature: 150-400℃
• Cooling method: air cooling
• Objective: To eliminate quenching stress and improve toughness.

Size specification
Common size specifications of SUS420J2 stainless steel are as follows:

• Thickness: 0.1mm-100mm (can be customized).
• Width: 10mm-2000mm (can be customized)
• Length: Usually sheet or coil, the length is customized according to customer requirements.

Application field
SUS420J2 stainless steel is widely used in the following fields due to its high hardness, wear resistance and corrosion resistance:

• Tool manufacturing: kitchen tools, industrial tools, scissors, etc.
• Medical instruments: scalpel, forceps, dental instruments, etc.
• Mold manufacturing: plastic mold, die casting mold, etc.
• Automotive industry: high wear parts, fasteners, etc.
• Industrial equipment: pump shaft, valve parts, bearings, etc.

SUS420J2 stainless steel is a kind of high-carbon martensitic stainless steel, which can obtain high hardness and wear resistance through proper heat treatment, and is suitable for manufacturing tools, molds and medical devices. The heat treatment process has a significant impact on the performance, and the appropriate heat treatment method should be selected according to the specific application scenario.