Scope – This specification is heavily utilized in petroleum and chemical construction applications and covers alloy steel and stainless steel bolting materials for high temperature or high pressure service. This specification is intended for use in pressure vessels, valves, flanges, and fittings.
Grades
|
B7 |
Alloy steel, AISI 4140/4142 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
|
Grade |
Markings |
Size |
Tensile ksi, min |
Yield, ksi,
min |
Elong, %, min |
RA % min |
Hardness Max |
| B7 |
B7 |
Up to 2-1/2 |
125 |
105 |
16 |
50 |
C35 |
| 2-5/8 – 4 |
115 |
95 |
16 |
50 |
C35 |
| 4-1/8 – 7 |
100 |
75 |
18 |
50 |
C35 |
| B8 Class 1 |
B8 |
All |
75 |
30 |
30 |
50 |
B96 |
| B8M Class 1 |
B8M |
All |
75 |
30 |
30 |
50 |
B96 |
| B8 Class 2 |
B8SH |
Up to 3/4 |
125 |
100 |
12 |
35 |
C35 |
| 7/8 – 1 |
115 |
80 |
15 |
35 |
C35 |
| 1-1/8 – 1-1/4 |
105 |
65 |
20 |
35 |
C35 |
| 1-3/8 – 1-1/2 |
100 |
50 |
28 |
45 |
C35 |
| B8M Class 2 |
B8MSH |
Up to 3/4 |
110 |
95 |
15 |
45 |
C35 |
| 7/8 – 1 |
100 |
80 |
20 |
45 |
C35 |
| 1-1/8 – 1-1/4 |
95 |
65 |
25 |
45 |
C35 |
| 1-3/8 – 1-1/2 |
90 |
50 |
30 |
45 |
C35 |
Chemical Properties
|
Element |
B7 (AISI 4140) |
B8 (AISI 304) |
B8M (AISI 316) |
| Carbon |
0.37 – 0.49 |
0.08 max |
0.08 max |
| Manganese |
0.65 – 1.10 |
2.00 max |
2.00 max |
| Phosphorus, max |
0.035 |
0.045 |
0.045 |
| Sulfur, max |
0.040 |
0.030 |
0.030 |
| Silicon |
0.15 – 0.35 |
1.00 max |
1.00 max |
| Chromium |
0.75 – 1.20 |
18.0 – 20.0 |
16.0 – 18.0 |
| Nickel |
|
8.0 – 11.0 |
10.0 – 14.0 |
| Molybdenum |
0.15 – 0.25 |
|
2.00 – 3.00 |
Recommended
Mating Materials
|
Bolt Grade |
Nuts Spec/Grade |
Washers Spec/Grade |
| B7 |
A194 Grade 2H |
F436 |
| B8 Class 1 |
A194 Grade 8 |
SS304 |
| B8M Class 1 |
A194 Grade 8M |
SS316 |
| B8 Class 2 |
A194 Grade 8 |
SS304 |
| B8M Class 2 |
A194 Grade 8M |
SS316 |
