top of page

What is stainless steel

Steel that contains more than 12% chromium and has a high resistance to corrosion by external media (acids, alkalis, salts) is called stainless steel.

Based on its chemical composition, stainless steel can be divided into:

  • Chromium stainless steel (magnetic)

  • Nickel-chromium stainless steel (non-magnetic)

Based on the metallographic structure, stainless steel can be mainly divided into three categories:

  • Martensitic stainless steel (13Cr series)

  • Ferritic stainless steel (18Cr series)

  • Austenitic stainless steel (18-8 series)​

AUSTENITIC

Austenitic stainless steel is the most common type of stainless steel. It is composed of 18% chromium and 8% nickel. A representative grade is SUS 304.

This type of stainless steel has the following characteristics: Non-magnetic (or weakly magnetic)，Cannot be strengthened by heat treatment, Good machinability

The main applications of 300 series stainless steel are general household applications such as kitchen utensils, building materials, medical and health equipment,  transportation vehicles,  mechanical equipment and parts.

MARTENSITIC

A representative grade of martensitic stainless steel is 410. Its chemical composition contains 13% chromium, less than 0.15% carbon, and a small amount of other alloying elements.

This type of stainless steel has the following characteristics: Magnetic, can be hardened by heat treatment to increase strength and difficult to form.

Due to the absence of nickel, its corrosion resistance is inferior to that of ordinary 304 stainless steel, so it can only be used in mild corrosive environments. Typical applications include: Bearings, medical instruments, and tools.

FERRITIC

A representative grade of ferritic stainless steel is 430. Its standard chemical composition is 16-18% chromium and low carbon content.

This type of stainless steel has the following characteristics: Magnetic, Good plasticity, Easy to form, Cannot be strengthened by heat treatment.

Typical applications include: Kitchen utensils, wire mesh, and ornaments.

​Type        Hardenability   Oxidation    High Temperature Low Temperature ​ Weldability    Magnetic
                                        Resistance     Strength               Toughness
 
Austenitic 
Ferritic
Martensitic
No
No
​Yes
Excellent
Excellent
​Poor
Excellent
Poor
​Good
Excellent
Poor
​Poor
Excellent
Poor
​Poor
No
Yes
​Yes

In addition to the above three categories, there are also precipitation hardening stainless steel and duplex stainless steel.

Precipitation hardening stainless steel:

  • Main components: chromium (Cr about 17%), nickel (Ni about 4%), 600 series stainless steel.

  • Characteristics: can be strengthened by heat treatment, high hardness, high temperature resistance, high corrosion resistance.

  • Applications: aerospace industry, high-precision components.

Duplex stainless steel:

  • Main components: chromium (Cr about 22%), nickel (Ni about 9%), molybdenum (Mo about 3%). Due to the presence of both ferritic and austenitic phases in the metallographic structure, it is called duplex stainless steel, such as Alloy 2205.

  • Characteristics: high strength, good machinability, excellent corrosion resistance, high yield strength.

  • Applications: chemical processing, pulp and paper industry, oil and gas industry, marine applications.

Stainless Steel
Chemical Composition

TYPE
​AUSTENITIC
MANTENSITIC
​FERRITIC
GRADE
C
Mn
Si
P
S
Ni
Cr
Mo
SUS304
  0.08            2.00            1.00           0.045          0.030        8.00~         18.00~            -
  MAX           MAX            MAX           MAX           MAX        10.50          20.00
SUS304L
  0.03            2.00            1.00           0.045          0.030        9.00~         18.00~            -
  MAX           MAX            MAX           MAX           MAX        13.00          20.00
SUS304S
  0.04           1.00~           0.75           0.040          0.030       10.00~       18.00~             -
  MAX           2.00            MAX           MAX           MAX        10.50          20.00
SUS309
  0.08            2.00            1.00           0.040          0.030       12.00~       22.00~             -
  MAX           MAX           MAX           MAX           MAX        15.00          24.00
SUS310S
  0.08            2.00            1.50           0.045          0.030       19.00~       24.00~             -
  MAX           MAX           MAX           MAX           MAX        22.00          26.00
SUS316
  0.08            2.00            1.00           0.045          0.030       10.00~       16.00~         2.00~
  MAX           MAX            MAX          MAX           MAX        14.00          18.00           3.00
SUS316L
  0.03            2.00            1.00           0.045          0.030       12.00~       16.00~         2.00~
  MAX           MAX            MAX          MAX           MAX        15.00          18.00           3.00
SUS305
  0.12            2.00            1.00           0.045          0.030       10.00~       17.00~            -
  MAX           MAX            MAX          MAX           MAX        13.00          19.00        
SUS410
  0.15            1.00            1.00           0.040          0.030         0.60          11.50~            -
  MAX           MAX            MAX          MAX           MAX          MAX          13.00           
SUS430
  0.12            1.00            0.75           0.040          0.030         0.60          16.00~           -
  MAX           MAX            MAX           MAX           MAX          MAX          18.00           

中良實業股份有限公司 Chung Liang Business Co., Ltd.

​711012 台南市歸仁區中山路三段487號

No. 487, Sec. 3, Zhongshan Rd., Guiren Dist., Tainan City 711012, Taiwan (R.O.C.)

TEL.  06-230-7686,  06-230-5914     FAX.  06-2307572

EMAIL.  chungliang1967@yahoo.com.tw

taiwantrade.com
DUNSCertified.png

 

©Chung Liang Business co., Ltd. All rights reserved 

bottom of page