SUS420J2 | Martensitic Stainless Steel

Stainless Steels


SUS420J2 | Martensitic Stainless Steel

Overview & Features

SUS420J2 is classified as a martensitic stainless steel, and although it is a stainless steel, can be hardened through quenching and tempering heat treatment. Because of its marketability, price, and usability, it is widely used in various fields.
Our annealed finish makes the carbides completely spheroidized, making processing easier and has excellent hardenability.

Main features of SUS420J2:

(1) Suitable for Wear and Heat Resistant Applications.
This grade is best suited for wear-resistant stainless steel applications, and can be used for heat-resistant applications due to its high tempering resistance.

(2) Less Mechanical and Physical Anisotropy
Due to the effect of microstructural transformation, it has less mechanical and physical anisotropy than austenitic spring materials that are hardened by cold rolling.

(3) It allows for savings in thickness and width.
Due to being a martensitic stainless steel, it has a higher Young's modulus compared to non-ferrous or austenitic stainless steels for springs. This allows the thickness and width of leaf springs to be reduced.

TOKKIN supplies a variety of stainless steels for springs as specified in JIS G4313.
Please refer to this page for the features and comparison of each grade of stainless steel for springs.

Examples of Applications

Puncture Needles (lancets), Medical knives / Hairdressing knives, Hinges, Thomson Blades/Pinnacle Blades, Doctor Blades, Scale, reed, Spinning Machine, Soldering Irons, Scrapers, Springs

Supported Shapes

Supported Range (COIL,SHEET)






COIL or SHEET less than 2000mm

This is the manufacturing range of coils and sheets we manufacture.

We manufacture in accordance with JIS G4313 standards.
Overseas standards are listed as equivalent or similar to our materials, so please use them as a reference.


SUS420J2 (G4313, G4305)










7.75 g/cm³

Specific Heat

460 J/(kg・K)

Electrical Resistivity

55 μΩ・cm

Young's Modulus

200 GPa

Thermal Expansion


Thermal Conductivity

24.7 W/(m・K)

Melting Range

1454-1510 ℃



We can manufacture according to your desired hardness between annealed to full hardened as shown in the table below.(The hardness of hardened steel strip is to be discussed each by each)
Some finishes may not be available depending on the thickness of the sheet, so please consult with us first.
*For ultra-thin foil, soft materials such as annealed or BA finish may not be applicable due to concerns about defects (folding, wrinkling, etc.).

SUS420J2 can be hardened by quenching and tempering.
The max quenched hardness is [589-640HV].
Please select tempering temperature according to required hardness and toughness by referencing quenching and tempering curve.

Steels for Blades

Material which is used to make various blades such as razor blades, shaver blades, and medical blades. Depending on the application and required properties, you can choose from a variety of options such as high carbon steel or martensitic stainless steel.

Martensitic Stainless Steels

They have a high carbon content and can acquire extremely high strength if quenched after stamping.

Hardened Stainless Steels

We provide quenched stainless steel strips.

Stainless Steels for Springs

This materials are possible to increase their hardness by rolling, they can be used as spring parts.


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