|
Alloy |
UNS Number |
SAE Number |
|
430 |
UNS S43000 |
GENERAL PROPERTIES
Stainless steel grade 430 is a non-hardenable steel containing straight chromium, and belongs to the ferritic group of steels. This steel is known for its good corrosion resistance and formability, coupled with practical mechanical properties. It can be used in certain chemical applications due to its resistance to nitric acid.
Grade 430F stainless steel is usually provided in bar form to be used in automatic screw machines.
Grade 434 has similar properties as grade 430, although it is a molybdenum-bearing version. The molybdenum content enhances its corrosion resistance.
RESISTANCE TO CORROSION
All ferritic grades, such as stainless steel grade 430, have excellent stress corrosion cracking resistance. Grade 430 has good corrosion resistance to numerous substances, such as certain organic acids and nitric acid. The corrosion resistance is maximized in well-polished or buffed condition. Its pitting and crevice corrosion resistance is quite similar to that of grade 304. 430F is a high-sulphur free machining grade, and therefore the resistance to pitting and crevice corrosion is comparatively lesser than those grades that are non-free machining.
PHYSICAL PROPERTIES
|
Melting Point |
Density |
Specific Gravity |
Modulus of Elasticity |
|
1425 – 1510 ℃ |
7.75g/cm3 |
7.75 |
200 GPa |
MECHANICAL PROPERTIES
|
Alloy |
Tensile Strength |
Yield Strength |
% Elongation |
|
430 Annealed * |
70,053.21 |
44,961.69 |
22 |
CHEMICAL PROPERTIES
|
Alloy |
C |
Si |
Mn |
P |
S |
Cr |
Fe |
|
430 |
0.08 |
1.00 |
1.00 |
0.04 |
0.02 |
16.00 – 18.00 |
Bal |
WELDING
To perform any welding, stainless steel grade 430 has to be pre-heated at 150-200°C (302-392°F). In case of embrittlement in the welded metal, the particular area can be post-weld annealed at 790-815°C (1454-1499°F); however grain refinement will not happen.
It is recommended that grade 430, 308L, 309 or 310 filler rod should be used based on the application.
Ductility of the welded products can be improved by annealing post-welding at temperatures of 760 to 815°C. However, this is not required for thin welded products. Welding of exhaust tubing of automobiles is carried out without filler rods.
HEAT TREATMENT
Solution annealing can be performed by heating stainless steel grade 430 to 815 - 845°C (1499-1553°F). Then it has to be slow furnace cooled to 600°C (1112°F) and followed by air-cooling in a quick manner - as slow cooling between 540 and 400°C (1004 and 752°F) tends to cause embrittlement.
For sub-critical annealing, heating should be performed to 760-815°C (1400-1499°F), followed by air-cooling or water quenching.
This stainless steel cannot be hardened by thermal treatment.
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