TOKKIN™ 350│Precipitation Hardening Stainless Steel for Bellows


Welded bellows, actuated valves for air conditioners, diaphragms for cooling equipment

Thickness: 0.010mm(Foil) - 2.0mm Width : 3.0mm-300mm |
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JAPAN
Product Overview
TOKKIN™ 350 is a precipitation hardening stainless steel with excellent yield strength and cyclic fatigue strength. Compared to other stainless steels, it has better weldability, corrosion resistance, and oxidation-resistant properties.
TOKKIN™ 350 Equivalency materials
AM350, UNS S35000, AISI 633, AMS 5548, ASTM A693(Type 633)
Features
TOKKIN™ 350 corresponds to JIS SUS633, and is a chromium–nickel–molybdenum stainless steel.
It has excellent workability when solution heat treated or annealed, and boasts high strength when heat treated. It also has excellent yield strength and cyclic fatigue strength.
How is TOKKIN™ 350 different from other precipitation hardening stainless steels?
Thanks to a higher Molybdenum(Mo) content than other precipitation hardening stainless steels (SUS631 and SUS632J1), TOKKIN™ 350 has excellent corrosion resistance and oxidation-resistant properties against sulfuric acid, hydrochloric acid, and other substances. It does not contain aluminum or titanium, which gives it excellent weldability.
For this reason, TOKKIN™ 350 is frequently used in applications requiring long life such as bellows, actuated valves for air conditioners, and diaphragms for cooling equipment.
General thickness materials are in stock.
When you absolutely need materials in a hurry, please ask us available stock.
We also have a stock of foils with a thickness of 0.10 mm or less, so we can provide them in small quantities.
We'll send you our Inventory List, Please request from here.
Standard
TOKKIN Designation |
USA |
others |
|||
UNS |
AMS |
AISI |
ASTM |
||
TOKKIN™ 350 |
S35000 |
5548 |
633 |
633 |
AM350 |
Chemical composition
TOKKIN Designation |
Chemical composition(%) |
|||||||||
C |
Si |
Mn |
P |
S |
Cr |
Ni |
Mo |
N |
その他 |
|
TOKKIN™ 350 |
0.07~ 0.11 |
≦0.50 |
0.50~ 1.25 |
≦0.040 |
≦0.030 |
16.00~ 17.00 |
4.00~ 5.00 |
2.50~ 3.25 |
0.07~ 0.13 |
Bal |
Tokkin Advantages
High quality and reliability
Our ability to produce uniform strength and thickness tolerances that are impossible to achieve using regular materials allows us to manufacture products that demonstrate stable strength in spring applications.
Moreover, we can produce excellent fatigue resistance and reliability by adjusting material structure and by creating a high degree of cleanliness via the careful management of manufacturing history and the adjustment of chemical composition.
Ultrathin foils
We can manufacture ultra thin sheets of 0.010 to 0.099 mm.
Flexible, small-lot production
We can manufacture standard lots weighing 300 kg,
and are also happy to consider smaller lots upon consultation.
(Requests for small-lot orders will be dealt with on a case-by-case basis.)
Ability to adjust materials to desired hardness
We make products to order, and can adjust hardness as required.
Select your surface finish
By changing the roll used in the rolling process, we can offer a bright or dull finish.
If required we can also provide a hairline finish (outsourced).
Physical properties
Finish |
Density |
Specific heat |
Electric resistance |
Coefficient of thermal expansion |
Thermal conductivity |
Young's modulus |
g/cm3 |
J(kg·K) |
μΩ·cm |
(25~100゜C)10-6/K |
(100ºC)W/(m·K) |
N/mm2 |
|
Annealed |
7.92 |
461 |
79 |
15.2 |
15.4 |
200,000 |
SCT 850 |
7.81 |
461 |
79 |
11.3 |
15.4 |
196,000 |
Mechanical properties
Finishing condition |
Annealed (BA 2B) |
SCT 850 |
||||||
Hardness |
Tensile strength |
Yield strength |
Elongation |
Hardness |
Tensile strength |
Yield strength |
Elongation |
|
Thickness (mm) |
HV |
N/mm2 |
N/mm2 |
% |
HV |
N/mm2 |
N/mm2 |
% |
0.030~0.051 |
≦266 |
≦1393 |
≦641 |
9≦ |
412~484 |
1276≦ |
1037≦ |
4≦ |
0.051~0.127 |
≦266 |
≦1372 |
≦627 |
10≦ |
412~484 |
1276≦ |
1037≦ |
6≦ |
0.127~0.254 |
≦266 |
≦1351 |
≦614 |
12≦ |
412~484 |
1276≦ |
1037≦ |
6≦ |
0.254~0.508 |
≦266 |
≦1331 |
≦600 |
14≦ |
412~484 |
1276≦ |
1037≦ |
8≦ |
耐食性
A - Excellent , B – Good , C – Moderate , D - Restricted
Humidity |
A |
Sodium Hydroxide |
C |
Phosphoric Acid |
D |
Sea Water |
D |
hydrochloric Acid |
D |
Sulfuric Acid |
D |
Salt Spray (NaCl) |
B |
Acetic Acid |
C |
Nitric Acid |
B |
Note:The 4-level rating scale is intended for comparative purposes only. Corrosion testing is recommended; factors which affect corrosion resistance include temperature, concentration, pH, impurities, aeration, velocity, crevices, deposits, metallurgical condition, stress, surface finish and dissimilar metal contact.
Precipitation Hardening
To ensure high hardness, TOKKIN™ 350 is annealed and then precipitation hardened. This process involves a primary hardening treatment, which transforms the metastable austenite structure into a martensite structure, and a precipitation hardening treatment, which completely hardens the material. TOKKIN™ 350 can be hardened using the SCT850 heat treatment conditions shown in the diagram on the right.
SUS631/632J1 and TOKKIN™ 350 are cold rolled and then precipitation hardened. This process forms an intermetallic compound containing minute amounts of aluminum in the martensite, which enables these materials to achieve extremely high hardness.