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Martensitic Stainless Steels

SUS420J2, RB-S, RB-X

Overview

SUS420J2, RB-S, and RB-X are classified as martensitic stainless steels and can be hardened through quenching and tempering heat treatment.
Martensitic stainless steel contains high carbon content and can be hardened through quenching, resulting in high strength. Furthermore, adjusting the tempering conditions can achieve various mechanical properties.
It also has high heat resistance and work-hardening properties, so it is used in various fields as shown in the application section.
However, due to its high carbon content, it has the disadvantage of being the most rust-prone of all stainless steels, so it requires anti-rust treatment similar to iron.

Examples of Applications

Knitting Needles, Reed, Spinning Machine, Doctor Blades, Industrial Knives, Scale, Soldering Irons, Scrapers, HDD Parts, Bearing Parts, Springs

Manufacturable Shapes

Manufacturable Range

Thickness: 0.050~2.5mm 
Width     : 3.0~300mm

Features

SUS420J2

It is classified as a martensitic stainless steel and because of its marketability and prce, it is widely used in various fields. Our annealed finish makes the carbides completely spheroidized, making processing easier.
RB-S
[TOKKIN Original Product]
It is classified as a martensitic stainless steel and with a higher Carbon content compared to SUS420J2, great hardening occurs during quenching, it has the highest level of hardness among stainless steels.Because it is quite hard even after annealing, less suitable for complex processing, but it is an ideal material for blades.
RB-X
[TOKKIN Original Product]
Although it is a stainless steel, RB-X can be hardened through quenching and tempering heat treatment because of its high Carbon content.It has superior corrosion resistance than RB-S due to higher Chromium content and addition of Nickel and Molybdenum. Because its Carbon content is slightly lower than RB-S, the hardness after quenching is slightly lower.

Standards

Equivalent overseas standards are for reference only.
RB-S and RB-X are TOKKIN original product.

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Grade Japan USA Europe International
JIS G4313,G4305 UNS AISI/ASTM EN ISO
SUS420J2 SUS420J2 S42000 420 1.4028
1.4034
 X30Cr13

Chemical Compositions

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Grade C Si Mn P S Cr Ni Mo Fe
SUS420J2 0.26~0.40 ≦1.00 ≦1.00 ≦0.040 ≦0.030 12.00~14.00 - - Bal.
RB-S 0.58~0.70 ≦1.00 ≦1.00 ≦0.040 ≦0.015 12.50~14.50 - - Bal.
RB-X 0.36~0.42​ ≦1.00 ≦1.50​ ≦0.040 ≦0.015 13.00~
14.5​0
≦0.50​ 0.60~1.00​ Bal.

Physical Properties

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Grade Density
[g/cm3
Specific Heat
[J/(kg・K)]
Electrical Resistance
[μΩ・cm]
Young's Modulus
[GPa]
Thermal Expansion
Coefficient
[×10-6/K]
Thermal Conductivity
[W/(m・K)]
Melting Point
[℃]
Magnetism
SUS420J2 7.75 460 55 200 10.3
(0~100℃)
24.7 1454~1510 Magnetism
RB-S 7.70 430 60 220 - 25.0 - Magnetism

Mechanical Properties

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Grade Hardness[HV]
 As Annealed / As Rolled After Heat Treatment
(Reference Values)
Annealed Full Hard Quenching and Tempering
SUS420J2 150~200 280~320 450~550
RB-S 230~270 310~360 600~750
RB-X 190~230 300~350 500~650

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Grade Temper / Finish Tensile Strength
[N/m㎡]
Elongation
[%]
SUS420J2 Annealed 540~655 20~30
Full Hard 880~1030 1~3

Graphs of Mechanical Properties

The mechanical properties resulting from rolling and quenching/tempering are shown in the figure below.
After quenching to the optimum condition, tempering should be performed according to the required properties of the product before use.
Since quenching and tempering conditions vary depending on the product size and required properties, they should be determined after testing.


Quenching and Tempering Curve of RB-S and SUS420J2

Advantages of TOKKIN

TOKKIN's materials for Martensitic Stainless Steels have the following advantages.
  • Microstructure can be controlled
    Controlling the microstructure improves hardenability and blade attachment workability.
    Because of its good hardenability, it is possible to harden materials with low temperature than that of normal quenching or short time, which reducing the burden of heat-treating furnace.
  • Thickness can be controlled
    We accommodate your order of special thickness in μ units required for cutter blades, razor blades and etc.
  • Small lot production is available
    Our standard MOQ is 300kg or more.

We welcome your questions and inquiries regarding materials.