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
Cr:17.00-2.00
Ni:-
Mo:1.75-2.50
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.
Excellent formability:
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.
ASTM A249/A249M Specification for Welded Austenitic Steel Boiler, Superheater, Heat-Exchanger, and Condenser tubes
ASTM A268/A268M Standard specification for Seamless and Welded Ferritic and Martensitic Stainless Steel Tubing for General Service
ASTM A269/A269M, ASME SA269/SA269M Specification for Seamless and Welded Austenitic Stainless Steel Tubing for General Service
ASTM A 270 Specification for Seamless and Welded Austenitic and Ferritic/Austenitic Stainless Steel Sanitary Tubing
ASTM A312/A312M, ASME SA312/SA312M Specification for Seamless and Welded Austenitic Stainless Steel Pipes
ASTM A 358/A 358M Specification for Electric-Fusion-Welded Austenitic Chromium-Nickel Alloy Steel Pipe for High-Temperature Service
ASTM A409/SA409 Welded Large Diameter Austenitic Steel Pipe for Corrosive or High Temperature Service
ASTM B515/ASME SB515
ASTM B516, ASME SB516,
ASTM A554 Specification for Welded Stainless Steel Mechanical Tubing
ASTM A632 Standard Specification for Seamless and Welded Austenitic Stainless Steel Tubing (Small-Diameter) for General Service
ASTM A688/SA688 Standard specification For Welded Austenitic Stainless Steel feedwater heater ‘U’ Tubes
ASTM A731/A731M Seamless and Welded Ferritic and Martensitic Stainless Steel Pipe
ASTM A 778 Specification for Welded, Unannealed Austenitic Stainless Steel Tubular Products
ASTM A789/A789M, ASME SA789/SA789M Seamless and Welded Ferritic/Austenitic Stainless Steel Tubing for General Service
ASTM A790/A790M, ASME SA790/SA790M Seamless and Welded Ferritic/Austenitic Stainless Steel Pipe
ASTM A 450/A 450M Specificaion for General Requirements for Carbon, Ferritic Alloy, and Austenitic Alloy Steel Tubes
ASTM A530/A530M Standard Specification for General Requirements for Specialized Carbon and Alloy Steel Pipe
ASTM A 999/A 999M Specification for General Requirements for alloy and Stainles Steel Pipe
ASTM A813/A813M Standard Specification for Single- or Double-Welded Austenitic Stainless Steel Pipe
ASTM A814/A814M Standard Specification for Cold-Worked Welded Austenitic Stainless Steel Pipe
ASTM A999/A999M Standard Specification for General Requirements for Alloy and Stainless Steel Pipe
ASTM A1016/A1016M Standard Specification for General Requirements for Ferritic Alloy Steel, Austenitic Alloy Steel, and Stainless Steel Tubes
German-Standards
DIN 2463-1Welded austenitic stainless steel tubes: dimensions and masses per unit length
DIN 17455 Welded circular stainless steel tubes with general quality requirements -Technical delivery conditions
DIN 17457 Welded circular austenitic stainless steel tubes subject to special requirements
EN Standards
EN 10216-5 Welded Stainless Steel Tube
EN 10217-7 Welded steel tubes for pressure purposes - Technical delivery conditions - Part 7: Stainless steel tubes
EN 10296-2 Welded circular steel tubes for mechanical and general engineering purposes - Technical delivery conditions - Part 2: Stainless steel
Australian Standards
AS 1528 Tubes (Stainless Steel) and Tube Fittings for the Food Industry.
JIS-Standards
JIS G 3447 Stainless Steel Sanitary Pipes
G 3448 Light Gauge Stainless Steel Tubes for Ordinary Piping
G 3459 Stainless Steel Pipes
G 3468 Large Diameter Welded Stainless Steel Pipes
G 3463 Stainless Steel Boiler and Heat Exchanger Tubes
G 3446 Stainless Steel Pipes for Machine and Structural Purposes