Stainless steel is divided into martensite and austenite, ferrite and duplex.

1. Martensitic chromium stainless steel is mainly low-carbon or high-carbon steel with chromium content in the range of 11.5%-18%. Designations 403, 410, 414, 416, 416 (Se), 420, 431, 440A, 440B and 440C, the corrosion resistance of these steels comes from «chromium». The martensitic stainless steels widely used in various countries are as follows:
1. Low and medium carbon 13% Cr steel
2. High carbon 18% Cr steel
3. Low-carbon nickel-containing (about 2%) 17% Cr steel.

2. Austenitic stainless steel has stable austenite structure when Cr contains about 18%, Ni 8%~10%, and C about 0.1%. Non-magnetic and has high toughness and plasticity, but the strength is low, it is impossible to strengthen it by phase transformation, it can only be strengthened by cold working.

3. Ferritic stainless steel has a chromium content of 11% to 30%, and has a body-centered cubic crystal structure. Generally does not contain nickel, sometimes contains a small amount of Mo, Ti, Nb and other elements, large thermal conductivity, small expansion coefficient, good oxidation resistance, excellent stress corrosion resistance and other characteristics, mostly used in the manufacture of atmospheric resistance, water vapor, water and oxidation Acid corrosion parts. Poor plasticity, plasticity and corrosion resistance after welding are significantly reduced.

4. Austenitic-ferrite duplex stainless steel is a stainless steel with austenite and ferrite structure each accounting for about half. Containing C is low, Cr content is 18%~28%, Ni content is 3%~10%. Some steels also contain alloying elements such as Mo, Cu, Si, Nb, Ti, and N. This type of steel has the characteristics of austenitic and ferritic stainless steel. Compared with ferrite, it has higher plasticity and toughness, no room temperature brittleness, and has significantly improved intergranular corrosion resistance and welding performance, while maintaining iron. The 475°C brittleness and high thermal conductivity of plain stainless steel are characterized by superplasticity. Compared with austenitic stainless steel, the strength is high and the resistance to intergranular corrosion and chloride stress corrosion is significantly improved. Duplex stainless steel has excellent pitting corrosion resistance and is also a nickel-saving stainless steel.

 

Stainless steel standard steel number comparison table
China Japan USA United Kingdom Germany France
GB1220-92 JIS AISI BS970 DIN17440 NFA35-575
GB3280-92
0Cr13 SUS410S S410
1Cr13 SUS410 410 410S21 X7Cr13 Z6C13
2Cr13 SUS420J1 420J1 420S29 X20Cr13 Z20C13
1Cr17 SUS430 430
7Cr17 SUS440A 440A
9Cr18 SUS440C 440C X105CrMo17 Z100CD17
0Cr18Ni9 SUS304 304 304S15 X5CrNi189 Z6CN18.09
00Cr18Ni9 SUS304L 304L 304S12 X2CrNi189 Z2CN18.09
0Cr17Ni12Mo2 SUS316 316 316S16 X5CrNiMo1812 Z6CND17.12
00Cr17Ni14Mo2 SUS316L 316L 316S12 X2CrNiMo1812 Z2CND17.12
0Cr18Ni11Ti SUS321 321 X10CrNiTi189 Z6CNT18.10
0Cr18Ni11Nb SUS347 347 347S17 X10CrNiNb189 Z6CNNb18.10
00Cr26Ni7Mo2Ti
00Cr26Ni17Mo2Ti

 

Chemical composition of martensite, ferrite, austenite, duplex stainless steel
Steel number C Si Mn Cr Ni Mo Ti Nb S P
2Cr18Ni9 0.12-0.22 ≤1.0 ≤2.0 17-19 8-11 ≤0.03 ≤0.035
1Cr18Ni9(304) ≤0.015 ≤1.0 ≤2.0 17-19 8-10 ≤0.03 ≤0.035
0Cr18Ni9(304L) ≤0.08 ≤1.0 ≤2.0 17-19 8-11 ≤0.03 ≤0.035
1Cr18Ni9Ti ≤0.12 ≤1.0 ≤2.0 17-19 8-11 5×(C-0.02~0.8) ≤0.03 ≤0.035
0Cr18Ni9Ti(321) ≤0.08 ≤1.0 ≤2.0 17-19 8-11 5×C%~0.7 ≤0.03 ≤0.035
0Cr18Ni11Nb(347) ≤0.08 ≤1.0 ≤2.0 17-19 9-12 ≤10×C% ≤0.03 ≤0.035
0Cr17Ni12Mo2(316) ≤0.08 ≤1.0 ≤2.0 16-19 11-15 1.8-2.5 5×C%~0.7 ≤0.03 ≤0.035
00Cr26NiMo2Ti ≤0.03 0.4-0.8 ≤1.5 25-27 6.5-7.5 1.5-2.5 0.3-0.5 ≤0.03 ≤0.035
1Cr13(410) ≤0.15 ≤1.0 ≤1.0 11.5-13.5 ≤0.03 ≤0.035
2Cr13(420) 0.16-0.25 ≤1.0 ≤1.0 12-14 ≤0.03 ≤0.035
3Cr13 0.26-0.35 ≤1.0 ≤1.0 12-14 ≤0.03 ≤0.035
4Cr13 0.36-0.45 ≤1.0 ≤1.0 12-14 ≤0.03 ≤0.035
1Cr17(430) ≤0.12 ≤0.8 ≤0.8 16-18 ≤0.03 ≤0.035
1Cr17Ti ≤0.12 ≤0.8 ≤0.8 16-18 5×C%~0.8 ≤0.03 ≤0.035
0Cr17Ti ≤0.08 ≤0.8 ≤0.8 16-18 5×C%~0.8 ≤0.03 ≤0.035
1Cr25Ti ≤0.12 ≤1.0 ≤0.8 20-27 5×C%~0.8 ≤0.03 ≤0.035

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