Wall Thickness (WT): Measured with a thickness gauge to ensure that the wall thickness at each point meets the standard wall thickness tolerance requirements (ASTM A312 has positive and negative deviation requirements for wall thickness, and the negative deviation of the nominal wall thickness usually does not exceed 12.5%).
Chemical Composition Analysis: Ensure that the chemical composition of the material meets the requirements of the grades in the ASTM A790 standard. Key elements include carbon (C), manganese (Mn), phosphorus (P), sulfur (S), silicon (Si), chromium (Cr), nickel (Ni), and molybdenum (Mo).
ASTM A790 UNS S31803 Duplex Stainless Steel Pipe Specification
High corrosion resistance: Excellent resistance to a variety of corrosive media (especially chloride environments), including resistance to chloride stress corrosion cracking, pitting and crevice corrosion.
High strength: The yield strength is usually about twice that of common austenitic stainless steel (such as 304L/316L), which means that thinner wall thickness can be allowed in the design, thereby reducing weight and possibly reducing costs.
Duplex structure: Composed of approximately half austenite and half ferrite, this unique microstructure gives it the advantages of both austenite (toughness, corrosion resistance) and ferrite (high strength, stress corrosion resistance).
Good weldability: Compared with other high-strength materials, it has better weldability.
Wide application: Commonly used in industries with high requirements for corrosion resistance and strength, such as oil and gas, chemical industry, seawater desalination, and papermaking.
ASTM A790 UNS S31803 Pipe Chemical Composition
CHEMICAL
LIMITS
C
Mn
P
S
Si
Ni
Cr
Mo
N
ASTM A790 S31803
MIN
4.5
21.00
2.50
0.08
MAX
0.03
2.00
0.03
0.02
1.00
6.5
23.00
3.50
0.20
ASTM A790 UNS S31803 Pipe Mechanical Property
MATERIAL
T.S (MPA)
Y.S (MPA)
EL %
HARDNESS
ASTM A790 S31803
620min
450min
25min
290max
Duplex Stainless Steel Pipe Dimension
ASTM A790 UNS S31803 duplex stainless steel pipe is a general purpose stainless steel pipe used in different industries. Its diameter ranges from 1/8” to 30”, and thickness ranges from SCH 5S to SCH 80S.
Stainless Steel Pipe (ASME B 36.19M)
Nominal Size
OD
Sch5s
Sch10s
Sch40s
Sch80s
DN
NPS
0
T
kg/m
T
kg/m
T
kg/m
T
kg/m
6
1/8
10.3
1.24
0.28
1.73
0.37
2.41
0.47
8
1/4
13.7
1.65
0.49
2.24
0.63
3.02
0.8
10
3/8
17.1
1.65
0.63
2.31
0.84
3.2
1.1
15
1/2
21.3
1.65
0.82
2.11
1
2.77
1.27
3.73
1.62
20
3/4
26.7
1.65
1.04
2.11
1.28
2.87
1.69
3.91
2.2
25
1
33.4
1.65
1.33
2.77
2.09
3.38
2.5
4.55
3.24
32
1 1/4
42.2
1.65
1.68
2.77
2.7
3.56
3.39
4.85
4.47
40
1 1/2
48.3
1.65
1.95
2.77
3.11
3.68
4.05
5.08
5.41
50
2
60.3
1.65
2.44
2.77
3.93
3.91
5.44
5.54
7.48
65
2 1/2
73.0
2.11
3.77
3.05
5.26
5.16
8.63
7.01
11.41
80
3
88.9
2.11
4.6
3.05
6.45
5.49
11.29
7.62
15.27
90
31/2
101.6
2.11
5.29
3.05
7.4
5.74
13.57
8.08
18.63
100
4
114.3
2.11
5.96
3.05
8.36
6.02
16.07
8.56
22.32
125
5
141.3
2.77
9.67
3.4
11.57
6.55
21.77
9.53
30.97
150
6
168.3
2.77
11.55
3.4
13.48
7.11
28.26
10.97
42.56
200
8
219.1
2.77
15.09
3.76
19.96
8.18
42.55
12.7
64.64
250
10
273.1
3.4
23.08
4.19
27.78
9.27
60.31
12.7
96.01
300
12
323.9
3.96
31.89
4.57
36
9.53
73.88
12.7
132.08
350
14
355.6
3.96
35.06
4.78
41.3
400
16
406.4
4.19
42.41
4.78
47.29
450
18
457.2
4.19
47.77
4.78
53.26
500
20
508
4.78
60.46
5.54
68.61
550
22
558.8
4.78
66.57
5.54
75.53
600
24
609.6
5.54
84.16
6.35
94.45
750
30
762
6.35
120.72
7.92
147.36
ASTM A790 UNS S31803 Duplex Stainless Steel Pipe Applications
Oil and gas industry: for offshore platforms, oil and gas extraction, transportation and processing equipment, especially in harsh environments containing chlorides.
Chemical and petrochemical industry: for pipelines, tanks and heat exchangers handling corrosive chemicals such as acids, alkalis and salts.
Desalination and water treatment: ideal for use in desalination plants, sewage treatment plants and seawater cooling systems.
Paper & Pulp Industry: Used in bleaching equipment, digesters and related piping, it can effectively resist corrosive chemicals.
Structures & Buildings: Structural components in coastal or corrosive environments where high strength and corrosion resistance are required.
Dimensional Inspection
Outside diameter (OD): Measured with calipers or OD gauge to check whether it is within the standard tolerance.
Wall Thickness (WT): Measured with a thickness gauge to ensure that the wall thickness at each point meets the standard wall thickness tolerance requirements (ASTM A312 has positive and negative deviation requirements for wall thickness, and the negative deviation of the nominal wall thickness usually does not exceed 12.5%).
Chemical Composition Analysis: Ensure that the chemical composition of the material meets the requirements of the grades in the ASTM A790 standard. Key elements include carbon (C), manganese (Mn), phosphorus (P), sulfur (S), silicon (Si), chromium (Cr), nickel (Ni), and molybdenum (Mo).
ASTM A790 UNS S31803 Duplex Stainless Steel Pipe Specification
High corrosion resistance: Excellent resistance to a variety of corrosive media (especially chloride environments), including resistance to chloride stress corrosion cracking, pitting and crevice corrosion.
High strength: The yield strength is usually about twice that of common austenitic stainless steel (such as 304L/316L), which means that thinner wall thickness can be allowed in the design, thereby reducing weight and possibly reducing costs.
Duplex structure: Composed of approximately half austenite and half ferrite, this unique microstructure gives it the advantages of both austenite (toughness, corrosion resistance) and ferrite (high strength, stress corrosion resistance).
Good weldability: Compared with other high-strength materials, it has better weldability.
Wide application: Commonly used in industries with high requirements for corrosion resistance and strength, such as oil and gas, chemical industry, seawater desalination, and papermaking.
ASTM A790 UNS S31803 Pipe Chemical Composition
CHEMICAL
LIMITS
C
Mn
P
S
Si
Ni
Cr
Mo
N
ASTM A790 S31803
MIN
4.5
21.00
2.50
0.08
MAX
0.03
2.00
0.03
0.02
1.00
6.5
23.00
3.50
0.20
ASTM A790 UNS S31803 Pipe Mechanical Property
MATERIAL
T.S (MPA)
Y.S (MPA)
EL %
HARDNESS
ASTM A790 S31803
620min
450min
25min
290max
Duplex Stainless Steel Pipe Dimension
ASTM A790 UNS S31803 duplex stainless steel pipe is a general purpose stainless steel pipe used in different industries. Its diameter ranges from 1/8” to 30”, and thickness ranges from SCH 5S to SCH 80S.
Stainless Steel Pipe (ASME B 36.19M)
Nominal Size
OD
Sch5s
Sch10s
Sch40s
Sch80s
DN
NPS
0
T
kg/m
T
kg/m
T
kg/m
T
kg/m
6
1/8
10.3
1.24
0.28
1.73
0.37
2.41
0.47
8
1/4
13.7
1.65
0.49
2.24
0.63
3.02
0.8
10
3/8
17.1
1.65
0.63
2.31
0.84
3.2
1.1
15
1/2
21.3
1.65
0.82
2.11
1
2.77
1.27
3.73
1.62
20
3/4
26.7
1.65
1.04
2.11
1.28
2.87
1.69
3.91
2.2
25
1
33.4
1.65
1.33
2.77
2.09
3.38
2.5
4.55
3.24
32
1 1/4
42.2
1.65
1.68
2.77
2.7
3.56
3.39
4.85
4.47
40
1 1/2
48.3
1.65
1.95
2.77
3.11
3.68
4.05
5.08
5.41
50
2
60.3
1.65
2.44
2.77
3.93
3.91
5.44
5.54
7.48
65
2 1/2
73.0
2.11
3.77
3.05
5.26
5.16
8.63
7.01
11.41
80
3
88.9
2.11
4.6
3.05
6.45
5.49
11.29
7.62
15.27
90
31/2
101.6
2.11
5.29
3.05
7.4
5.74
13.57
8.08
18.63
100
4
114.3
2.11
5.96
3.05
8.36
6.02
16.07
8.56
22.32
125
5
141.3
2.77
9.67
3.4
11.57
6.55
21.77
9.53
30.97
150
6
168.3
2.77
11.55
3.4
13.48
7.11
28.26
10.97
42.56
200
8
219.1
2.77
15.09
3.76
19.96
8.18
42.55
12.7
64.64
250
10
273.1
3.4
23.08
4.19
27.78
9.27
60.31
12.7
96.01
300
12
323.9
3.96
31.89
4.57
36
9.53
73.88
12.7
132.08
350
14
355.6
3.96
35.06
4.78
41.3
400
16
406.4
4.19
42.41
4.78
47.29
450
18
457.2
4.19
47.77
4.78
53.26
500
20
508
4.78
60.46
5.54
68.61
550
22
558.8
4.78
66.57
5.54
75.53
600
24
609.6
5.54
84.16
6.35
94.45
750
30
762
6.35
120.72
7.92
147.36
ASTM A790 UNS S31803 Duplex Stainless Steel Pipe Applications
Oil and gas industry: for offshore platforms, oil and gas extraction, transportation and processing equipment, especially in harsh environments containing chlorides.
Chemical and petrochemical industry: for pipelines, tanks and heat exchangers handling corrosive chemicals such as acids, alkalis and salts.
Desalination and water treatment: ideal for use in desalination plants, sewage treatment plants and seawater cooling systems.
Paper & Pulp Industry: Used in bleaching equipment, digesters and related piping, it can effectively resist corrosive chemicals.
Structures & Buildings: Structural components in coastal or corrosive environments where high strength and corrosion resistance are required.
On June 3, 2025, we received a request for quotation from a new customer in China for a batch of ASTM A790 UNS S31803 duplex stainless steel pipe. The customer has strict requirements on the specification, tolerance, surface quality and third-party testing and certification of the tubes, and focuses on the product’s corrosion resistance and delivery lead time.
ZIZI is a company specializing in the production and processing of pipes and fittings. The pipes and pipe fittings we produce are mainly used in chemical, petroleum, natural gas, water conservancy, electric power, marine engineering and other fields. The products mainly include seamless pipes, welded pipes, butt-welded pipe fittings, high-pressure forged pipe fittings and flanges of various sizes. The materials include carbon steel, stainless steel, alloy steel, low-temperature steel, duplex steel, base alloy, etc.
Dimensional Inspection
Outside diameter (OD): Measured with calipers or OD gauge to check whether it is within the standard tolerance.
Wall Thickness (WT): Measured with a thickness gauge to ensure that the wall thickness at each point meets the standard wall thickness tolerance requirements (ASTM A312 has positive and negative deviation requirements for wall thickness, and the negative deviation of the nominal wall thickness usually does not exceed 12.5%).
Chemical Composition Analysis: Ensure that the chemical composition of the material meets the requirements of the grades in the ASTM A790 standard. Key elements include carbon (C), manganese (Mn), phosphorus (P), sulfur (S), silicon (Si), chromium (Cr), nickel (Ni), and molybdenum (Mo).
ASTM A790 UNS S31803 Duplex Stainless Steel Pipe Specification
High corrosion resistance: Excellent resistance to a variety of corrosive media (especially chloride environments), including resistance to chloride stress corrosion cracking, pitting and crevice corrosion.
High strength: The yield strength is usually about twice that of common austenitic stainless steel (such as 304L/316L), which means that thinner wall thickness can be allowed in the design, thereby reducing weight and possibly reducing costs.
Duplex structure: Composed of approximately half austenite and half ferrite, this unique microstructure gives it the advantages of both austenite (toughness, corrosion resistance) and ferrite (high strength, stress corrosion resistance).
Good weldability: Compared with other high-strength materials, it has better weldability.
Wide application: Commonly used in industries with high requirements for corrosion resistance and strength, such as oil and gas, chemical industry, seawater desalination, and papermaking.
ASTM A790 UNS S31803 Pipe Chemical Composition
CHEMICAL
LIMITS
C
Mn
P
S
Si
Ni
Cr
Mo
N
ASTM A790 S31803
MIN
4.5
21.00
2.50
0.08
MAX
0.03
2.00
0.03
0.02
1.00
6.5
23.00
3.50
0.20
ASTM A790 UNS S31803 Pipe Mechanical Property
MATERIAL
T.S (MPA)
Y.S (MPA)
EL %
HARDNESS
ASTM A790 S31803
620min
450min
25min
290max
Duplex Stainless Steel Pipe Dimension
ASTM A790 UNS S31803 duplex stainless steel pipe is a general purpose stainless steel pipe used in different industries. Its diameter ranges from 1/8” to 30”, and thickness ranges from SCH 5S to SCH 80S.
Stainless Steel Pipe (ASME B 36.19M)
Nominal Size
OD
Sch5s
Sch10s
Sch40s
Sch80s
DN
NPS
0
T
kg/m
T
kg/m
T
kg/m
T
kg/m
6
1/8
10.3
1.24
0.28
1.73
0.37
2.41
0.47
8
1/4
13.7
1.65
0.49
2.24
0.63
3.02
0.8
10
3/8
17.1
1.65
0.63
2.31
0.84
3.2
1.1
15
1/2
21.3
1.65
0.82
2.11
1
2.77
1.27
3.73
1.62
20
3/4
26.7
1.65
1.04
2.11
1.28
2.87
1.69
3.91
2.2
25
1
33.4
1.65
1.33
2.77
2.09
3.38
2.5
4.55
3.24
32
1 1/4
42.2
1.65
1.68
2.77
2.7
3.56
3.39
4.85
4.47
40
1 1/2
48.3
1.65
1.95
2.77
3.11
3.68
4.05
5.08
5.41
50
2
60.3
1.65
2.44
2.77
3.93
3.91
5.44
5.54
7.48
65
2 1/2
73.0
2.11
3.77
3.05
5.26
5.16
8.63
7.01
11.41
80
3
88.9
2.11
4.6
3.05
6.45
5.49
11.29
7.62
15.27
90
31/2
101.6
2.11
5.29
3.05
7.4
5.74
13.57
8.08
18.63
100
4
114.3
2.11
5.96
3.05
8.36
6.02
16.07
8.56
22.32
125
5
141.3
2.77
9.67
3.4
11.57
6.55
21.77
9.53
30.97
150
6
168.3
2.77
11.55
3.4
13.48
7.11
28.26
10.97
42.56
200
8
219.1
2.77
15.09
3.76
19.96
8.18
42.55
12.7
64.64
250
10
273.1
3.4
23.08
4.19
27.78
9.27
60.31
12.7
96.01
300
12
323.9
3.96
31.89
4.57
36
9.53
73.88
12.7
132.08
350
14
355.6
3.96
35.06
4.78
41.3
400
16
406.4
4.19
42.41
4.78
47.29
450
18
457.2
4.19
47.77
4.78
53.26
500
20
508
4.78
60.46
5.54
68.61
550
22
558.8
4.78
66.57
5.54
75.53
600
24
609.6
5.54
84.16
6.35
94.45
750
30
762
6.35
120.72
7.92
147.36
ASTM A790 UNS S31803 Duplex Stainless Steel Pipe Applications
Oil and gas industry: for offshore platforms, oil and gas extraction, transportation and processing equipment, especially in harsh environments containing chlorides.
Chemical and petrochemical industry: for pipelines, tanks and heat exchangers handling corrosive chemicals such as acids, alkalis and salts.
Desalination and water treatment: ideal for use in desalination plants, sewage treatment plants and seawater cooling systems.
Paper & Pulp Industry: Used in bleaching equipment, digesters and related piping, it can effectively resist corrosive chemicals.
Structures & Buildings: Structural components in coastal or corrosive environments where high strength and corrosion resistance are required.
