ASTM A790 / A790M – 16: Standard Specification for Seamless and Welded Ferritic/Austenitic Stainless Steel Pipe

ASTM A790 / A790M – 16

Standard Specification for Seamless and Welded Ferritic/Austenitic Stainless Steel Pipe

ASTM A790 covers seamless and straight-seam welded ferritic/austenitic duplex stainless steel pipe for general corrosive service, with particular emphasis on resistance to stress corrosion cracking. The pipe shall be made by the seamless or an automatic welding process, with no addition of filler metal in the welding operation. Heat analysis shall be made to determine the percentages of the elements specified. Tension tests, hardening tests, flattening tests, hydrostatic test and nondestructive electric tests shall be made to conform to the specified requirements.

This abstract is a brief summary of the referenced standard. It is informational only and not an official part of the standard; the full text of the standard itself must be referred to for its use and application. This specification covers seamless and straight-seam welded ferritic/ austenitic stainless steel pip intended for general corrosive service, with particular emphasis on resistance to stress corrosion cracking. These steel are susceptible to embrittlement if used for prolonged periods at elevated temperatures.

Optional supplementary requirements are provided for pipe when a greater degree of testing is desired. These supplementary requirements call for additional tests to be made and, when desired, one or more of these may be specified in the order.

Appendix X1 of this specification lists the dimensions of welded and stainless steel seamless pipe as shown in ANSI B36.19. Pipe having other dimensions may be furnished provided such pipe complies with all other requirements of this specification.

The values stated in either inch-pound units or SI units are to be regarded separately as standard. Within the text, the SI units are shown in brackets. The values stated in each system are not exact equivalents; therefore, each system must be used independently of the other. Combining values from the two systems may result in nonconformance with the specification. The inch-pound units shall apply unless the M designation of this specification is specified in the order.

The dimensionless designator NPS (nominal pipe size) has been substituted in this standard for such traditional terms as nominal diameter, size, and nominal size.

1. Scope* 
1.1 This specification2 covers seamless and straight-seam welded ferritic/austenitic steel pipe intended for general corrosive service, with particular emphasis on resistance to stress corrosion cracking. These steels are susceptible to embrittlement if used for prolonged periods at elevated temperatures. 
1.2 Optional supplementary requirements are provided for pipe when a greater degree of testing is desired. These supplementary requirements call for additional tests to be made and, when desired, one or more of these may be specified in the order. 
1.3 Appendix X1 of this specification lists the dimensions of welded and seamless stainless steel pipe as shown in ANSIB36.19. Pipe having other dimensions may be furnished provided such pipe complies with all other requirements of this specification. 
1.4 The values stated in either inch-pound units or SI units are to be regarded separately as standard. Within the text, the SI units are shown in brackets. The values stated in each system are not exact equivalents; therefore, each system must be used independently of the other. Combining values from the two systems may result in nonconformance with the specification. The inch-pound units shall apply unless the designation of this specification is specified in the order. 
 

2. Referenced Documents 
2.1 ASTM Standards: 
A 370 Test Methods and Definitions for Mechanical Testing of Steel Products 
A 941 Terminology Relating to Steel, Stainless Steel, Related Alloys and Feroalloys 
A 999/A 999M Specification for General Requirements for Alloy and Stainless Steel Pipe 
E 213 Practice for Ultrasonic Examination of Metal Pipe and Tubing 
E 309 Practice for Eddy-Current Examination of Steel Tubular Products Using Magnetic Saturation 
E 381 Method of Macroetch Testing Steel Bars, Billets, Blooms, and Forgings 
E 426 Practice for Electromagnetic (Eddy-Current) Examination of Seamless and Welded Tubular Products, Austenitic Stainless Steel and Similar Alloys 
E 527 Practice for Numbering Metals and Alloys (UNS) 
2.2 ANSI Standards:
B1.20.1 Pipe Threads, General Purpose 
B36.10 Welded and Seamless Wrought Steel Pipe 
B36.19 Stainless Steel Pipe 
2.3 SAE Standard:
SAE J 1086 
2.4 Other Standard:
SNT-TC-1A Personal Qualification and Certification in Nondestructive Testing 
 

3. Ordering Information 
4.1 Orders for material under this specification should include the following, as required, to describe the desired material adequately: 
4.1.1 Quantity (feet, metres, or number of lengths), 
4.1.2 Name of material (ferritic/austenitic steel pipe), 
4.1.3 Process (seamless or welded), 
4.1.4 Grade (see Table 1), 
4.1.5 Size (NPS designator or outside diameter and schedule number of average wall thickness), 
4.1.6 Length (specific or random) (see Section 11), 
4.1.7 End finish (section on ends of Specification A 999/A 999M), 
4.1.8 Optional requirements (product analysis, Section 9;hydrostatic test or nondestructive electric test, Section 14), 
4.1.9 Test report required (section on certification of SpecificationA 999/A 999M), 
4.1.10 Specification designation, and 
4.1.11 Special requirements and any supplementary requirementsselected. 
 

4. General Requirements 
Material furnished under this specification shall conform to the applicable requirements of the current edition of Specification A 999/A 999M unless otherwise provided herein

Tensile and Hardness Requirements A

UNS Designation

Tensile Strength,
min, ksi[MPa]

Yield Strength,
min, ksi [MPa]

Elongation in 2 in. or 50 mm,min, %

Hardness, max

Brinell

 HRC

S31803

 90 [620]

65 [450]

25

290

30

S32205

 95 [655]

70 [485]

25

290

30

S31500

 92 [630]

64 [440]

30

290

30

S32550

 110 [760]

 80 [550]

15

297

31

S31200

100 [690]

 65 [450]

25

280

 . . .

S31260B

 100 [690]

65 [450]

25

290

30

S32001

 90 [620]

65 [450]

25

290

30

S32304

OD 1 in. [25 mm] and Under

100 [690]

65 [450]

25

 . . .

. . .

OD over 1 in. [25 mm]

87 [600]

58 [400]

25

290

30

S39274

116 [800]

 80 [550]

15

310

 . . .

S32750

116 [800]

 80 [550]

15

300

32

S32760

109 [750]

 80 [550]

25

300

S32900

90 [620]

70 [485]

20

271

28

S32950C

100 [690]

 70 [480]

20

290

30

S39277

120 [825]

 90 [620]

25

290

30

S32520

112 [770]

80 [550]

25

310

       S32906

Wall below 0.40 in.(10 mm)

116 [800]

 94 [650]

25

300

32

Wall 0.40 in. (10 mm) and above

109 [750]

80 [550]

25

300

32

S32003

90 [620]

65 [450]

25

290

30

A For tubing smaller than 1⁄2 in. [12.7 mm] in outside diameter, the elongation values given for strip specimens in Table 4 shall apply. Mechanical property requirements do not apply to tubing smaller than 1⁄8 in. [3.2 mm] in outside diameter or with walls thinner than 0.015 in. [0.4 mm]. 
B Prior to A 789/A 789M–87, the values for S31260 were: 92 ksi tensile strength, 54 ksi yield strength, and 30 % elongation. 
C Prior to A 789/A 789M–89, the tensile strength value was 90 ksi for UNS S32950.

Chemical Requirements:

UNS
Designation A 

C

 Mn

 P

S

Si

 Ni

Cr

Mo

 N

 Cu

 Others

S31803

0.030 max

2.00 max

0.030 max

0.020 max

1.00 max

4.5–6.5

21.0–23.0

 2.5–3.5

0.08–0.20

. . .

. . .

S32205

0.030 max

2.00 max

0.030 max

0.020 max

1.00 max

4.5–6.5

22.0–23.0

3.0–3.5

0.14–0.20

. . .

 . . .

S31500

0.030 max

1.20–2.00

0.030 max

0.030 max

1.40–2.00

4.3–5.2

18.0–19.0

2.50–3.00

0.05–0.1

S32550

0.04 max

1.50 max

0.040 max

0.030 max

1.00 max

4.5–6.5

24.0–27.0

2.9–3.9

0.10–0.25

1.50–2.50

 . . .

S31200

0.030 max

2.00 max

 0.045 max

0.030 max

1.00 max

5.5–6.5

24.0–26.0

1.20–2.00

0.14–0.20

 . . . .

 . . . .

S31260

0.030 max

1.00 max

0.030 max

0.030 max

0.75 max

5.5–7.5

24.0–26.0

2.5–3.5

0.10–0.30

0.20–0.80

W 0.10–0.50

S32001

0.030 max

4.00–6.00

0.040 max

0.030 max

 1.00 max

1.0–3.0

19.5–21.5

0.60 max

0.05–0.17

1.00 max

 . . .

S32304

0.030 max

2.50 max

0.040 max

0.040 max

1.00 max

3.0–5.5

21.5–24.5

 0.05–0.60

0.05–0.20

0.05–0.60

 . . .

S39274

0.030 max

 1.00 max

0.030 max

0.020 max

0.80 max

6.0–8.0

24.0–26.0

2.5–3.5

0.24–0.32

0.20–0.80

W 1.50–2.50

S32750

0.030 max

1.20 max

0.035 max

0.020 max

0.80 max

6.0–8.0

24.0–26.0

3.0–5.0

 0.24–0.32

0.50 max

 . . .

S32760

0.05 max

1.00 max

0.030 max

0.010 max

1.00 max

6.0–8.0

24.0–26.0

3.0–4.0

0.20–0.30

 0.50–1.00

W 0.50–1.00
     40 minB

S32900

0.08 max

1.00 max

0.040 max

0.030 max

0.75 max

2.5–5.0

23.0–28.0

1.00–2.00

. . .

 . . .

 . . .

S32950

0.030 max

2.00 max

0.035 max

0.010 max

0.60 max

3.5–5.2

26.0–29.0

1.00–2.50

 0.15–0.35

 . . .

. . .

S39277

0.025 max

0.80 max

0.025 max

0.002 max

0.80 max

6.5–8.0

24.0–26.0

3.00–4.00

0.23–0.33

1.20–2.00

W 0.80–1.21

S32520

0.030 max

1.50 max

0.035 max

0.020 max

0.80 max

5.5–8.0

23.0–25.0

 3.–5.

0.20–0.35

0.50–3.00

 . . .

S32906

0.030 max

1.50 max
     0.80 min

0.030 max

0.030 max

0.50 max

7.5 max
     5.8 min

30.0 max
     28.0 min

2.60 max
     1.50 min

0.40
     .30

0.80
     . . .

. . .
     . . .

S32003

0.030 max

2.00 max

0.030 max

 0.020 max

1.00 max

3.0-4.0

19.5-22.5

1.50-2.00

0.14-0.20

 . . .

 . . .

A New designation established in accordance with Practice E 527 and SAE J1086. 
B % Cr + 3.3 3 %Mo + 16 3 % N.

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