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

  • Length. Normally furnished in 10 ft (3 m) lengths or over.

  • Length Tolerances. No tube shall be shorter than specified. No tube shall be more than 0.25 in (6 mm) over that specified.

  • 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

    Ovalityt< 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/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

    1. Includes ovality tolerance except for thin wall pipe (i.e. t>3% OD).

    2. Min wall thickness = Nominal wall thickness (t) x 0.875. Not applicable if filler metal added.

    3. 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.

  • 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.

  • 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.

  • 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.

  • S1 Intergranular Corrosion Bend Test. One end of one length from each 2500 ft (760 m) tested. Test in accordance with Practice E.

  • S1 Packing Requirement. Ends protected with wooden or plastic plugs.

  • S1 Hydrostatic Test. Each length tested as per ASTM pipe general requirements in Section 3.

  • 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.

  1. Titanium >5 x Carbon, 0.70% max

  2. Niobium + Tantalum: >10 x Carbon, and 1.10% max

Note

– Niobium is sometimes referred to as Columbium.

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