ASTM A333 is the standard specification that covers seamless and welded steel pipes designed for low-temperature service and other applications requiring notch toughness. Among the various grades, ASTM A333 Grade 6 is the most widely used for service temperatures down to -45°C.
Grade 6 features excellent mechanical properties, with a minimum yield strength of 240 MPa and a minimum tensile strength of 415 MPa, making it well-suited for pressure systems and structural applications operating in cold environments.
Union Steel Industry Co., Ltd is professional steel pipes manufacturer, for more details, please contact:sales@union-steels.com
Chemical Requirements of A333 Grade 6 Pipes
|
|
|
Composition, %
|
|
|
Element
|
Grade 1
|
Grade 3
|
Grade 6
|
|
Carbon, max
|
0.30
|
0.19
|
0.30
|
|
Manganese
|
0.40–1.06
|
0.31–0.64
|
0.29–1.06
|
|
Phosphorous, max
|
0.025
|
0.025
|
0.025
|
|
Sulfur, max
|
0.025
|
0.025
|
0.025
|
|
Silicon
|
0.18 -0.37
|
0.10 min
|
|
Nickel
|
3.18–3.82
|
|
For each 0.01% decrease in carbon content below 0.30%, an increase of 0.05% in manganese content above 1.06% is allowed, up to a maximum manganese content of 1.35%.
When Grade 6 is specified under ASTM A333, the use of any alloying elements not listed for that grade is not permitted. However, the addition of elements necessary for steel deoxidation is allowed.
Tensile Requirements of A333 Grade 6 Pipe
The material shall conform to the requirements as proscribed:
|
|
|
Grade 1
|
Grade 3
|
Grade 6
|
|
|
|
psi
|
MPa
|
psi
|
MPa
|
psi
|
MPa
|
|
Tensile Strength, min
|
55,000
|
380
|
65,000
|
450
|
60,000
|
415
|
|
|
Yield Strength, min
|
30,000
|
205
|
35,000
|
240
|
35,000
|
240
|
|
|
|
|
Longitudinal
|
Transverse
|
Longitudinal
|
Transverse
|
Longitudinal
|
Transverse
|
|
Elongation in 2 in. or 50 mm, (or 4D), min, %:
|
|
|
|
|
Basic minimum elongation for walls 5/16 in. [8 mm] and over in thickness, strip tests, and for all small sizes tested in full section
|
35
|
35
|
30
|
20
|
30
|
16.5
|
|
|
When the standard round 2-in. or 50-mm gage length or proportionally smaller size test specimen with the gage length equal to 4D (4 times the diameter) is used
|
28
|
20
|
22
|
14
|
22
|
12
|
|
|
For strip tests, a deduction for each 1/32in. [0.8 mm] decrease in wall thickness below 5/16 in. [8 mm] from the basic minimum elongation of the following percentage
|
1.75
|
1.25
|
1.50
|
1.00
|
1.50
|
1.00
|
|
|
|
|
|
|
|
|
|
|
|
|
Elongation in 2 in. or 50 mm, min, %:
|
|
|
Wall Thickness
|
Grade 1
|
Grade 3
|
Grade 6
|
|
in.
|
mm
|
Longitudinal
|
Transverse
|
Longitudinal
|
Transverse
|
Longitudinal
|
Transverse
|
|
5/16 (0.312)
|
8
|
35
|
25
|
30
|
20
|
30
|
16
|
|
9/32 (.281)
|
7.2
|
33
|
24
|
28
|
19
|
28
|
15
|
|
1/4 (.250)
|
6.4
|
32
|
23
|
27
|
18
|
27
|
15
|
|
7/32 (.219)
|
5.6
|
30
|
|
26
|
|
26
|
|
|
3/16 (.188)
|
4.8
|
28
|
|
24
|
|
24
|
|
|
5/32 (.156)
|
4
|
26
|
|
22
|
|
22
|
|
|
1/8 (.125)
|
3.2
|
25
|
|
21
|
|
21
|
|
|
3/32 (.094)
|
2.4
|
23
|
|
20
|
|
20
|
|
|
1/16 (.063)
|
1.6
|
21
|
|
18
|
|
18
|
|
Impact Requirements of A333 Grade 6 Pipe
For Grades 1, 3 and 6, the notched-bar impact properties of each set of three impact specimens, including specimens for the welded joint in welded pipe with wall thicknesses of 0.120 in. [3 mm] and larger, shall not be less than the values prescribed:
|
Size of Specimen, min
|
Minimum Average Notched Bar Impact Value of Each Set of Three Specimens
|
Minimum Notched Bar Impact Value of One Specimen Only of a Set
|
Impact Temperature
|
|
|
ft-lbf
|
J
|
ft-lbf
|
J
|
Grade
|
Min Impact
Test Temp
|
|
10 by 10
|
13
|
18
|
10
|
14
|
|
F
|
C
|
|
10 by 7.5
|
10
|
14
|
8
|
11
|
1
|
-50
|
-45
|
|
10 by 6.67
|
9
|
12
|
7
|
9
|
3
|
-150
|
-100
|
|
10 by 5
|
7
|
9
|
5
|
7
|
6
|
-50
|
-45
|
|
10 by 3.33
|
5
|
7
|
3
|
4
|
|
|
|
|
10 by 2.5
|
4
|
5
|
3
|
4
|
|
|
|
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