ASTM A320
Mechanical and chemical requirements for rolled or forged carbon alloy steel and stainless steel bolts, including externally threaded bolts, screws, and studs. Applications include alloy steel bolts for use in pressure vessels, flanges, valves, and fittings for low-temperature service.
| Grades |
|
| L7 Alloy steel |
AISI 4140/4142 Quenched and tempered |
| L43 Alloy steel |
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 |
| Grade |
Size |
tensile ksi min |
Yield, ksi, min |
Charpy Impact 20-ft-lbf @ temp |
Elong, % min |
RA, % MIN |
|
| L7 |
Up to 2 1/2 |
125 |
105 |
-150 F |
16 |
50 |
|
| L43 |
Up to 4 |
125 |
105 |
-150 F |
16 |
50 |
|
| B8 Class 1 |
All |
75 |
30 |
N/A |
30 |
50 |
|
| B8M Class 1 |
All |
75 |
30 |
N/A |
30 |
50 |
|
| B8 Class 2 |
Up to 3/4 |
125 |
100 |
N/A |
12 |
35 |
|
| |
7/8 - 1 |
115 |
80 |
N/A |
15 |
35 |
|
| |
1 1/8- 1 1/4 |
105 |
65 |
N/A |
20 |
35 |
|
| |
1 3/8- 1 1/2 |
100 |
50 |
N/A |
28 |
45 |
|
| B8M Class 2 |
Up to 3/4 |
110 |
95 |
N/A |
15 |
45 |
|
| |
7/8- 1 |
100 |
80 |
N/A |
20 |
45 |
|
| |
1 1/8- 1 1/4 |
95 |
65 |
N/A |
25 |
45 |
|
| |
1 3/8- 1 1/2 |
90 |
50 |
N/A |
30 |
45 |
|
| Grade |
Nuts |
|
|
Washers |
| L7 |
A194 Grade 4 or 7 |
|
|
F436 |
| L43 |
A194 Grade 4 or 7 |
|
|
F436 |
| B8 Class 1 |
A194 Grade 8 |
|
|
SS304 |
| B8M Class 1 |
A194 Grade 8M |
|
|
SS316 |
| B8 Class 2 |
A194 Grade 8, strain hardendd |
|
|
SS304 |
|
