ASTM A 778 – 90a: Welded, Unannealed Austenitic Stainless Steel Tubular Products
ASTM A 778 – 90a
Welded, Unannealed Austenitic Stainless Steel Tubular Products
This specification covers straight seam and spiral butt seam welded unannealed austenitic stainless steel tubular products for low and moderate temperatures and corrosive service where heat treatment is not necessary for corrosion resistance. This specification has minimum mandatory testing and examination requirements.
Dimensions and Tolerances
-
Tube sizes normally furnished to this specification are as follows: – 3 in (75 mm) to 48 in (1200 mm) OD – 0.062 in (1.5 mm) to 0.5 in (12.5 mm) wall thickness
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Length. Normally furnished in 10 ft (3 m) lengths or over.
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Length Tolerances. No tube shall be shorter than specified. No tube shall be more than 0.25 in (6 mm) over that specified.
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Straightness. 0.25 in (6 mm) maximum deviation from 10 ft (3 m) straight edge.
Cross-sectional tolerances
NPS
Outside Diameter (OD)1
Wall Thickness(t)2
Ovality3 t< 3%OD
Under
Over
Under
Over
in
mm
in
mm
%
%
%
1/2to 11/2
0.031
0.8
0.015
0.4
12.5
12.5
1.5
>11/2 to 4
0.031
0.8
0.031
0.8
12.5
12.5
1.5
>4 to 8
0.031
0.8
0.062
1.6
12.5
12.5
1.5
>8 to 12
0.031
0.8
0.093
2.4
12.5
12.5
1.5
>12 to 18
0.031
0.8
0.093
2.4
12.5
12.5
1.5
>18 to 26
0.031
0.8
0.125
3.2
12.5
12.5
1.5
>26 to 34
0.031
0.8
0.156
4.0
12.5
12.5
1.5
>34 to 48
0.031
0.8
0.187
4.8
12.5
12.5
1.5
Notes
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Includes ovality tolerance except for thin wall pipe (i.e. t>3% OD).
-
Min wall thickness = Nominal wall thickness (t) x 0.875. Not applicable if filler metal added.
-
Ovality = Difference between maximum and minimum OD. For t>3% OD, ovality is within OD tolerances.
Manufacture
-
-
Material. Refer to chemical composition table. Made from flat rolled sheet, coil or plate.
-
Manufacture. Shielded arc-welding process (manual or automatic). Filler metal may be used. Tubes <14 in (350 mm) have single longitudinal weld or spiral butt weld. Tubes >14 in may have up to 3 longitudinal welds. Circumferential welds are permitted if agreed with purchaser.
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Heat Treatment. None.
-
Marking. ASTM tube general requirements apply plus ‘HT-O’ to indicate no heat treatment.
Finish and Repair
-
Weld Bead. Reinforcement bead <1/16 in (1.6 mm) may be left on either surface of tube, or it may be removed.
-
Weld Defect Repair. Defects may be removed to sound metal and rewelded.
-
Finish. Tube will be clean and free of scale.
Ordering Information
Item
Notes
Specification number
ASTM A778 – 90a
Size
Outside diameter and wall thickness
Quantity
Random or specified lengths. Total length or number of lengths
Name of material
Welded, unannealed austenitic stainless steel tubes
Grade
Selected from chemical composition table
Weld seam
Straight seam or spiral butt seam welded
Test report
DIN 50049.3.1.B standard, or DIN 50049.3.1.C optional (3rd party witness test) at extra cost
Options and supplementary requirements
Refer to optional and supplementary requirements S1 to S5
Note
– The above table is based on ASTM requirements except with regard to test reports, where standard practice options are added. See also page 10-2 for ISO based ordering and general delivery information.
Mandatory Testing
-
Transverse Tension Test. One test across weld per lot. Alternative test may be agreed for tube <8 in (200 mm) OD.
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Transverse Guided-Bend Weld Test. Two test specimens taken transversely from weld for each lot. Test is acceptable if no cracks or other defect exceed 1/8 in (3 mm) in length, in any direction. Cracks <1.4 in (6 mm) along edge of specimen are not considered. Alternative Flattening Test (S5) may be specified for tube <8 in OD.
-
Lot sizes are: 400 for <3 in OD tube 300 for 3 to <8 in OD tube 200 for 8 to <14 in OD tube 100 for >14 in OD tube
Optional and Supplementary Requirements
-
Alternative to transverse tension test may be specified for <8 in OD tube.
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S1 Etching Tests. One end of one length from each 2500 ft (760 mm) tested. Test in accordance with Method E340 to show sound, homogeneous, reasonably uniform material, free of injurous laminations, cracks or objectionable defects.
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S1 Intergranular Corrosion Bend Test. One end of one length from each 2500 ft (760 m) tested. Test in accordance with Practice E.
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S1 Packing Requirement. Ends protected with wooden or plastic plugs.
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S1 Hydrostatic Test. Each length tested as per ASTM pipe general requirements in Section 3.
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S1 Flattening Test. One test per lot. A section of welded tube >4 in (100 mm) long is flattened with weld at 90° from direction of applied force. No cracks shall occur until distance between plates is <0.5 x OD.
Tensile Requirements
Grade |
UNS |
Tensile Strength min |
Yield Strength min |
Elongation in 2 in (50 mm) min |
||
ksi |
MPa |
ksi |
MPa |
% |
||
TP304L |
S30403 |
70 |
485 |
25 |
170 |
40 |
TP316L |
S31603 |
70 |
485 |
25 |
170 |
40 |
TP317L |
S31703 |
75 |
515 |
30 |
205 |
35 |
TP321 |
S32100 |
75 |
515 |
30 |
205 |
40 |
TP347 |
S34700 |
75 |
515 |
30 |
205 |
40 |
Chemical Compositions
Composition Percentage, max or range |
||||||||||
Grade |
UNS |
&DUERn C |
0DQJDQHVe Mn |
3KRVSKRUXs P |
6XOSKXr S |
6LOLFRn Si |
1LFNHlNi |
&KURPLXm Cr |
0RO\EGHQXm Mo |
Note |
TP304L |
S30403 |
0.030 |
2.00 |
0.045 |
0.030 |
1.00 |
8.00- 13.00 |
18.00-20.00 |
– |
1,3 |
TP316L |
S31603 |
0.030 |
2.00 |
0.045 |
0.030 |
1.00 |
10.00- 15.00 |
16.00-18.00 |
2.00-3.00 |
1,3 |
TP317L |
S31703 |
0.030 |
2.00 |
0.045 |
0.030 |
1.00 |
11.00- 14.00 |
18.00-20.00 |
3.00-4.00 |
1,3 |
TP321 |
S32100 |
0.08 |
2.00 |
0.045 |
0.030 |
1.00 |
9.00- 12.00 |
17.00-19.00 |
– |
2,4 |
TP347 |
S34700 |
0.08 |
2.00 |
0.045 |
0.030 |
1.00 |
9.00- 13.00 |
17.00-19.00 |
– |
2,5 |
Composition Notes
1 Carbon analysis reporting to the nearest 0.001% is required. 2 Carbon analysis reporting to the nearest 0.01% is required. 3 Nitrogen 0.10% max.
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Titanium >5 x Carbon, 0.70% max
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Niobium + Tantalum: >10 x Carbon, and 1.10% max
Note
– Niobium is sometimes referred to as Columbium.