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ASTM A320
Rods Specification-NINGBO BOLT |
ASTM A320 Rods Specification
ASTM A320 is a
standard material specification covering alloy and stainless steel bolting
materials for pressure vessels, valves, flanges, and fittings for low
temperature services. ASTM A320 specification includes chemical composition,
mechanical properties, dimensional reference standards, recommended nuts and
washers for grades like L7, L43, B8, B8M, B8C, B8T and many others with notch
toughness requirements.
Supplementary
requirements includes Impact properties and hardness testing of class 2 bolting
materials for ASME applications.
ASTM A320 Grades
|
Grade |
Raw Material |
|
L7 |
13%
Chromium Ferritic Steel |
|
L7M |
Chromium
Molybdenum Alloy Steel, Quenched & Tempered |
|
L43 |
Chromium
Molybdenum Alloy Steel, Quenched & Tempered |
|
B8 |
AISI 304
Stainless Steel, Carbide Solution Treated |
|
B8 Class 2 |
AISI 304
Stainless Steel, Carbide Solution Treated and Strain Hardened |
|
B8M |
AISI 316
Stainless Steel, Carbide Solution Treated |
|
B8M Class 2 |
AISI 316
Stainless Steel, Carbide Solution Treated and Strain Hardened |
|
B8T |
AISI 321
Stainless Steel, Carbide Solution Treated |
|
B8T Class 2 |
AISI 321
Stainless Steel, Carbide Solution Treated and Strain Hardened |
|
B8C |
AISI 347
Stainless Steel, Carbide Solution Treated |
ASTM A320 Chemical
Composition
|
Element |
Grade L7, L7M |
Grade L43 |
Grade B8 |
Grade B8M |
Grade B8T |
Grade B8C |
|
Carbon |
0.38 - 0.48 |
0.38 - 0.43 |
0.08 max |
0.08 max |
0.08 max |
0.08 max |
|
Manganese,
max |
0.75 - 1.00 |
0.75 - 1.00 |
2.00 max |
2.00 |
2.00 |
1.00 |
|
Phosphorus,
max |
0.035 |
0.035 |
0.045 |
0.045 |
0.045 |
0.040 |
|
Sulfur, max |
0.040 |
0.040 |
0.030 |
0.030 |
0.030 |
0.030 |
|
Silicon |
0.15 - 0.35 |
0.15 - 0.35 |
1.00 max |
1.00 |
1.00 |
1.00 max |
|
Nickel |
- |
0.40 - 0.70 |
8.0 - 11.0 |
10.0 - 14.0 |
9.0 - 12.0 |
8.00 -
11.00 |
|
Chromium |
0.80 - 1.10 |
0.40 - 0.60 |
18.0 - 20.0 |
16.0 - 18.0 |
17.0 - 19.0 |
18.0 - 20.0 |
|
Molybdenum |
0.15 - 0.25 |
0.20 - 0.30 |
-
|
2.0 - 3.0 |
- |
- |
|
Titanium |
- |
- |
- |
- |
5 x C, min |
- |
ASTM A320 Mechanical
Properties
|
Grade |
Diameter, in. |
Tensile
Strength, ksi |
Yield
Strength ksi |
Elongation, % |
Reduction, % |
Hardness |
|
B7 |
2.5 and
under |
125 |
105 |
16 |
50 |
321 HBW or
35 HRC |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
B7M |
4 and under |
125 |
105 |
16 |
50 |
321 HBW or
35 HRC |
|
|
|
|
|
|
|
|
B16 |
2.5 and
under |
100 |
80 |
18 |
50 |
321 HBW or
35 HRC |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
B8, B8M,
B8C, B8T Class 1 |
1" and
under |
75 |
30 |
30 |
50 |
223 HBW or
96 HRB |
|
B8, B8C,
B8T, Class 2 |
3/4 and
under |
125 |
100 |
12 |
35 |
321 HBW or
35 HRC |
|
Over 3/4 to
1, inclusive |
115 |
80 |
15 |
30 |
321 HBW or
35 HRC |
|
Over 1 to 1
1/4", inclusive |
105 |
65 |
20 |
35 |
321 HBW or
35 HRC |
|
Over 1 1/4"
to 1 1/2", inclusive |
100 |
50 |
28 |
45 |
321 HBW or
35 HRC |
|
B8M, Class
2 |
3/4 and
under |
110 |
95 |
15 |
45 |
321 HBW or
35 HRC |
|
over 3/4 to
1, inclusive |
100 |
80 |
20 |
45 |
321 HBW or
35 HRC |
|
over 1 to 1
1/4, inclusive |
95 |
65 |
25 |
45 |
321 HBW or
35 HRC |
|
over 1-1/4"
to 1-1/2", inclusive |
90 |
50 |
30 |
45 |
321 HBW or
35 HRC |
ASTM A320 Impact Test
Requirements
|
Grade |
Test
Temperature |
|
＜F |
＜C |
|
L7M, L70,
L71, L72, L73 |
-100 |
-73 |
|
L7, L7A,
L7B, L7C |
-150 |
-101 |
|
L43 |
-150 |
-101 |
|
L1 |
-100 |
-73 |
ASTM A320 Temperature
Requirement For Impact Testing
|
Size of
specimen, mm |
Minimum
Impact Value Required for Average of Each Set of Three Specimens,
ft.lbf(J) |
Minimum
Impact Value permitted for One Specimen Only of a Set, ft.lbf(J) |
|
All Grade
Except L1A |
|
10 by 10 |
20 [27] |
15 [20] |
|
10 by 7.5 |
16 [22] |
12 [16] |
|
Grade L1 |
|
10 by 10 |
40 [54] |
30 [41] |
|
10 by 7.5 |
32 [44] |
24 [32] |
ASTM A320 Recommended
Nuts & Washers
|
Bolt Grade |
Nut Grade |
Washer
Grade |
|
L7 |
ASTM A194
Grade 7 |
ASTM F436
Type 1 |
|
L7M |
ASTM A194
Grade 7M |
ASTM F436
Type 1 |
|
L43 |
ASTM A194
Grade 4 OR Grade 7 |
ASTM F436
Type 1 |
|
B8 |
ASTM A194
Grade 8 |
AISI 304 |
|
B8M |
ASTM A194
Grade 8M |
AISI 316 |
|
B8T |
ASTM A194
Grade 8T |
AISI 321 |
|
B8C |
ASTM A194
Grade 8C |
AISI 347 |
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