TOKKIN™ 350 | Precipitation Hardening Stainless Steel｜TOKUSHU KINZOKU EXCEL CO., LTD.(TOKKIN)

Stainless Steels

Precipitation Hardening

TOKKIN™ 350 | Precipitation Hardening Stainless Steel

Fatigue Properties

High Corrosion Resistance

Precipitation/Age Hardening

Product Lineup

Request a Quote/Samples

Overview & Features

TOKKIN™ 350 is a Cr-Ni-Mo stainless steel. In solution heat-treated and annealed conditions, it boasts excellent workability and high strength by heat treatment.
Compared to other precipitation hardening stainless steels, the addition of Molybdenum provides superior corrosion resistance and oxidation resistance, and the absence of Aluminum and Titanium provides good weldability. It also has excellent yield strength and cyclic fatigue strength, and is used for bellows, diaphragms, actuation valves, etc. which require long life under cyclic stress.

Examples of Applications

Bellows, Diaphragms, Valves, Air Conditioner, Actuated Valves, Watch Parts

Available Shapes

Manufacturable Range (COIL, SHEET)

Thickness

0.030-1.0mm

Width

3.0-300mm

Length

COIL or SHEET less than 2000mm

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

Standard

Chemical Composition

Physical Properties

Mechanical Properties

Heat Treatment

Corrosion Resistance

Related Pages

Standards

UNS

S35000

ASTM

A693(Type 633)

AMS

5548

AISI

633

Chemical Composition

Physical Properties

Annealed Condidtion

Density

7.92 g/cm³

Specific Heat

461 J/(kg・K)

Electrical Resistivity

79 μΩ・cm

Thermal Expansion

15.2×10^-6/K (25～100℃)

Thermal Conductivity

15.4 W/(m・K) (100℃)

Mechanical Properties

In general, TOKKIN350 is supplied in 2B finish with ligt skin-passed of annaled material to compensate for distortion. Mechanical properties of 2B finish meet the annealed condition requirements of the AMS5548 standard.

Heat Treatment

Age hardening(Precipitation Hardening) can be performed on TOKKIN350.
precipitation hardened is performed from the annealed state to obtain high strength through two treatments:
①primary hardening, which transforms the metastable austenite structure in the annealed state into martensite. ②precipitation hardening, which completely hardens the structure.
Please see the figure below for heat treatment conditions.

Corrosion Resistance

Corrosion resistance in each corrosive environment is shown in the table below.

Related Pages

High-Strength, High-Ductility
JIN™

"TOKKIN's uniquely designed production method for JIN™ brings you a material that combines high strength and excellent workability that cannot be obtained with ordinary manufacturing methods. The balance of Yield stress (YS) exceeds 35,000 MPa x Elongation (EL) is among the highest in the world."

Learn More

Materials for Bellows

We manufacture TOKKIN 350 and various other metals for bellows, and we can propose materials and specifications according to required properties such as strength, corrosion resistance, and heat resistance.

Learn More

Precipitation Hardening Stainless Steels

These grades were developed with the concept of steels that are easy to form like austenitic stainless steels, and provide high strength like that of martensitic stainless steels.

Learn More

Related Products

TOKKIN™ 350 JIN™ | High-Strength and High-Ductility Stainless Steel

By applying our proprietary "JIN™" process to our own grade TOKKIN 350 material, we have achieved high strength, excellent workability, and high reliability that cannot be obtained with ordinary manufacturing methods.

Main features of TOKKIN 350 JIN:

(1)Both High Strength and High Ductility
Typical values: Yield Strength(Ys) over 1500 MPa & Elongation(El) over 20%

(2)Low Mechanical Anisotropy
Greater flexibility in part design and stamping

(3)No Heat Treatment required after processing
Dimensional changes due to heat treatment are eliminated and dimensional accuracy is stabilized.

(4)Higher corrosion resistance than SUS316L
This material can meet the needs of customers who want to improve workability while maintaining the same strength as SUS301, or who want to omit precipitation hardening heat treatment of SUS631 or SUS632J1.

Dowlnload data sheet or more details on this page.

Learn More

SUS301 | Austenitic Stainless Steel

SUS301 is a steel grade in which Chromium and Nickel are reduced from a typical austenitic stainless steel grade SUS304, so that it can be easily hardened by processing. Full hard finished materials such as EH and SEH, have extremely high strength equivalent to hardened materials by only cold rolling.
It is an ideal material for spring parts uses that require durability, such as spiral springs and membrane switches. In addition, its properties of austenitic stainless steel allow the product to be used in a variety of environments without plating to prevent rust.

We supply 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.

Learn More

SUS631 (17-7PH) | Precipitation Hardening Stainless Steel

SUS631 is the most typical precipitation hardening type steel that can be heat treated to increase hardness while retaining the excellent performance of 18-8 stainless steel.
From the softest solution-treated to the hardest full hard rolled, depending on the processing and application, it is possible to have a strength second only to high-carbon martensitic quenched materials by applying various heat treatments.
In the solution heat-treated state, more than 30% elongation allows for strong processing such as drawing.
Please note that the material is weakly magnetic in the solution heat-treated state, but becomes quite strongly magnetic after precipitation hardening treatment.

This material is hard to obtain due to its relatively small distribution volume, and most of the materials distributed in stock sales are 3/4H finish. However, we can provide from the softest material in solution heat-treated condition (A material) to the hardest material with full hard finish (EH) per your use and processing method in small lot.

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.

Learn More