Composition, properties and uses of SUS444 and TTS443
SUS 444 steel belongs to high alloy ferritic stainless steel. Compared with SUS 430, it contains about 1.0% more chromium and adds alloy element Mo, so it has good pitting corrosion, crevice corrosion and stress corrosion resistance, and its corrosion resistance is even better than SUS 304 and SUS 316 in some fields. 2. With the addition of stabilizing elements such as Ti, Nb and Zr, the steel has good intergranular corrosion resistance and high temperature oxidation resistance.
1, chemical composition:
Standard: GB/T (China); JIS (Japan)
Brand name: Ocr18Mo2Nb (China); SUS444 (Japan)
Specific ingredients: (less than)
C: less than 0.025
Si: less than 1
Mn: less than 1
P: less than 0.03
S: less than 0.03
N: less than 0.025
Others: Ti/Nb/Zr or combination 8 (C+N) ~0.8
2. Mechanical and physical properties: (refer to JIS standard)
Yield strength (N/m:): greater than 245
Tensile strength (N/m:): greater than 410
Elongation (%): less than 20
Hardness HB: less than 217
Hardness HRB: less than 96
Hardness HV: less than 230
N value: 0.20
R value: 1.2
Coefficient of thermal expansion: 11.5
Thermal conductivity: 25.9
3. Main uses:
SUS 444 is the most heat-resistant steel in ferrite steel. Its high temperature oxidation resistance is excellent within 1000 ~C. On the contrary, 304 is most susceptible to corrosion when the water temperature reaches 50-90 ~C. Compared with 304, 444 steel has high chlorine resistance, excellent stress corrosion resistance and pitting corrosion resistance. It is not easy to scale and has strong heat absorption effect. Its corrosion resistance is similar to SUS316 steel.
Based on the characteristics of 444 steel, it is mainly used to manufacture water storage tank, solar water heater, heat exchanger and video machinery.
Properties and uses of TTS443 steel
TTS443 nickel-free stainless steel, with chromium content as high as 21%, has the same excellent corrosion resistance as SUS304, excellent formability, good high temperature performance, but the price is only 65% of SUS304. It is suitable for household appliances, vehicle parts, kitchen machinery, interior and exterior building decorative materials, container interior panel and other fields.
Excellent corrosion resistance:
Chromium content is as high as 21% and has the same excellent corrosion resistance as 304.
Because of the reduction of impurities such as carbon and ammonia, and the addition of titanium element with stabilizing effect, good corrosion resistance can also be maintained after welding.
Mechanical properties are superior to 403.
Price advantage and stability:
No nickel is added, so the price is cheaper than 403.
Without adding nickel and molybdenum, the price of these two metals will not be affected.