2024年6月13日发(作者：衷棠华)
ASTM A320
Scope
Originally approved in 1948, the ASTM A320 specification covers alloy steel and
stainless steel bolting materials for low temperature service. This standard covers
rolled, forged, or strain hardened bars, bolts, screws, studs, and stud bolts used for
pressure vessels, valves, flanges, and fittings. Like the ASTM A193 specification,
unless otherwise specified, the 8UN thread series is specified on fastener larger than
1” in diameter.
Below is a basic summary of a few of the common grades within the ASTM A320
specification. A number of other less common grades of ASTM A320 exist, but not
covered in the description below.
Grades
L7 Alloy steel
L43 Alloy steel
AISI 4140/4142 Quenched and tempered
AISI 4340 Quenched and tempered
B8 Class 1 Stainless steel AISI 304, carbide solution treated
B8M Class 1 Stainless steel AISI 316, carbide solution treated
B8 Class 2 Stainless steel AISI 304, carbide solution treated, strain hardened
B8M Class 2 Stainless steel AISI 316, carbide solution treated, strain hardened
Mechanical Properties
Tensile, Yield,
ksi, min ksi, min
125
125
75
75
125
115
105
105
105
30
30
100
80
65
Charpy Impact
Elong,
20-ft-lbf RA, %, min
%, min
@ temp
-150° F
-150° F
N/A
N/A
N/A
N/A
N/A
16
16
30
30
12
15
20
50
50
50
50
35
35
35
Grade
L7
L43
B8
Class 1
B8M
Class 1
B8
Class 2
Size
Up to 2
1
/
2
Up to 4
All
All
Up to
3
/
4
7
/
8
- 1
1
1
/
8
- 1
1
/
4
1
3
/
8
- 1
1
/
2
Up to
3
/
4
7
/
8
- 1
B8M
Class 2
1
1
/
8
- 1
1
/
4
100
110
100
95
90
50
95
80
65
50
N/A
N/A
N/A
N/A
N/A
28
15
20
25
30
45
45
45
45
45 1
3
/
8
- 1
1
/
2
Recommended Nuts and Washers
Grade
L7
L43
B8 Class 1
B8M Class 1
B8 Class 2
Nuts
A194 Grade 4 or 7
A194 Grade 4 or 7
A194 Grade 8
A194 Grade 8M
A194 Grade 8, strain hardened
Washers
F436
F436
SS304
SS316
SS304
B8M Class 2 A194 Grade 8M, strain hardened SS316
2024年6月13日发(作者：衷棠华)
ASTM A320
Scope
Originally approved in 1948, the ASTM A320 specification covers alloy steel and
stainless steel bolting materials for low temperature service. This standard covers
rolled, forged, or strain hardened bars, bolts, screws, studs, and stud bolts used for
pressure vessels, valves, flanges, and fittings. Like the ASTM A193 specification,
unless otherwise specified, the 8UN thread series is specified on fastener larger than
1” in diameter.
Below is a basic summary of a few of the common grades within the ASTM A320
specification. A number of other less common grades of ASTM A320 exist, but not
covered in the description below.
Grades
L7 Alloy steel
L43 Alloy steel
AISI 4140/4142 Quenched and tempered
AISI 4340 Quenched and tempered
B8 Class 1 Stainless steel AISI 304, carbide solution treated
B8M Class 1 Stainless steel AISI 316, carbide solution treated
B8 Class 2 Stainless steel AISI 304, carbide solution treated, strain hardened
B8M Class 2 Stainless steel AISI 316, carbide solution treated, strain hardened
Mechanical Properties
Tensile, Yield,
ksi, min ksi, min
125
125
75
75
125
115
105
105
105
30
30
100
80
65
Charpy Impact
Elong,
20-ft-lbf RA, %, min
%, min
@ temp
-150° F
-150° F
N/A
N/A
N/A
N/A
N/A
16
16
30
30
12
15
20
50
50
50
50
35
35
35
Grade
L7
L43
B8
Class 1
B8M
Class 1
B8
Class 2
Size
Up to 2
1
/
2
Up to 4
All
All
Up to
3
/
4
7
/
8
- 1
1
1
/
8
- 1
1
/
4
1
3
/
8
- 1
1
/
2
Up to
3
/
4
7
/
8
- 1
B8M
Class 2
1
1
/
8
- 1
1
/
4
100
110
100
95
90
50
95
80
65
50
N/A
N/A
N/A
N/A
N/A
28
15
20
25
30
45
45
45
45
45 1
3
/
8
- 1
1
/
2
Recommended Nuts and Washers
Grade
L7
L43
B8 Class 1
B8M Class 1
B8 Class 2
Nuts
A194 Grade 4 or 7
A194 Grade 4 or 7
A194 Grade 8
A194 Grade 8M
A194 Grade 8, strain hardened
Washers
F436
F436
SS304
SS316
SS304
B8M Class 2 A194 Grade 8M, strain hardened SS316