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ASTM A789 Seamless and Welded Ferritic/Austenitic Stainless Steel Tubing for General Service
This specification covers grades of average wall thickness, or, if specified on the order, minimum wall thickness, of stainless steel tubing for services requiring general corrosion resistance, with particular emphasis on resistance to stress corrosion cracking. These steels are susceptible to embrittlement if used for prolonged periods at elevated temperatures.
UNS number: S32750 (Ferritic/Austenitic steel)
Ordering Information
Orders for product under this specification should include the following, as required, to describe the desired material adequately:
1 Quantity (feet, metres, or number of lengths),
2 Name of product (seamless or welded tubes),
3 Grade,
4 Size (outside diameter and average wall thickness, unless minimum wall thickness is specified),
5 Length (specific or random),
6 Optional requirements,
7 Test report required (see the Inspection section of Specification A1016/A1016M),
8 Specification designation, and
9 Special requirements.
Manufacture
The tubes shall be made by the seamless or welded process with no filler metal added.
Heat Treatment
Temperature: 1025–1125°C
Quench: rapid cooling in air or water
Chemical requirements, %,
C: ≤0.030
Mn: ≤1.20
P: ≤0.035
S: ≤0.020
Si: ≤0.80
Cr: 24.0-26.0
Ni: 6.0-8.0
Mo: 3.0-5.0
N: 0.24-0.32
Cu: ≤0.50
Tensile requirements
Tensile Strength: ≥800MPa
Yield Strength.: ≥550MPa
Elongation in 2 in. or 50 mm, %: ≥15
Hardness:
HBW: ≤300
HRC: ≤32
Each tube shall be subjected to the nondestructive electric test or the hydrostatic test.
Permissible Variations in Dimensions
Size, Outside Diameter, mm |
Permissible Variations in Outside Diameter, mm |
Average Wall Permissible Variations in Wall Thickness, % |
≤12.7 | 0.13 | ±15 |
12.7<D≤38.1 | 0.13 | ±10 |
38.1<D≤88.9 | 0.25 | ±10 |
88.9<D≤139.7 | 0.38 | ±10 |
139.7<D≤203.2 | 0.76 | ±10 |
Contact Person: Mr. Sam Cui
Tel: +86 130 3189 1590