ASTM A320 L43 Stud bolt is normally applied for the stud bolt size over than 2 1/2″,which is used for low temperature applications.ASTM A320 Grade L43 is a standard material specification for alloy steel bolting materials for pressure vessels, valves, flanges, and fittings for low temperature services.
A320 L7 Stud bolt
A320 L43 Stud bolt
The mechanical and chemical makeup of both A320 Grades L7 and L43, is almost same,but the main difference is that the raw material used to make A320 L7 fasteners is typically 4140, whereas the raw material used to make A320 L43 is 4340.You may find the ASTM A320 specification showing below.
A320 Grades
| L7 Alloy steel |
AISI 4140/4142 Quenched and tempered |
| L43 Alloy steel |
AISI 4340 Quenched and tempered |
A320 Mechanical Properties
| Grade |
Size |
Tensile, ksi, min |
Yield, ksi, min |
Charpy Impact 20-ft-lbf @ temp |
Elong, %, min |
RA, %, min |
| L7 |
Up to 21⁄2 |
125 |
105 |
-150° F |
16 |
50 |
| L43 |
Up to 4 |
125 |
105 |
-150° F |
16 |
50 |
A320 Chemical Properties
| Element |
L7 (AISI 4140) |
L43 (AISI 4340) |
| Carbon |
0.37 - 0.49% |
0.38 - 0.43% |
| Manganese |
0.65 - 1.10% |
0.75 - 1.00% |
| Phosphorus, max |
0.035% |
0.035% |
| Sulfur, max |
0.040% |
0.040% |
| Silicon |
0.15 - 0.35% |
0.15 - 0.35% |
| Chromium |
0.75 - 1.20% |
0.70 - 0.90% |
| Nickel |
|
1.65 - 2.00% |
| Molybdenum |
0.15 - 0.25% |
0.20 - 0.30% |
A320 Recommended Hardware
| Grade |
Nuts |
Washers |
| L7 |
A194 Grade 4 or 7 |
F436 |
| L43 |
A194 Grade 4 or 7 |
F436 |
Astm A320 Grade L7Download pdf File
I. Strength Grades
| DIN 931/933 |
Grade 4.6, 4.8, 5.6, 5.8, 8.8, 10.9, 12.9 |
| DIN 931/933 |
SUS 304, 316 |
| ASTM A307 |
Grade A & B |
| ASTM A320, A320M |
Grade L7, L7M,L43, B8, B8M |
| ASTM A325, A325M |
Grade 8.8 |
| ASTM A490, A490M |
Grade 10.9 |
| ASTM A193/A193M |
Grade B7, B7M, B8, B8M, B16 |
ASTM A320 Grade L7 Stud bolts with two ASTM A194 Gr 7 nuts
ASTM A320 Grade L7M Stud bolts with two ASTM A194 Gr 7M nuts
High Strength Stud Bolt A320 Gr L7 A194-Gr 7
High Strength Stud Bolt 5 8 A320 Gr L7 A194 Gr 7
ASTM A320 / A320M 22Download pdf File
Standard Specification for Alloy-Steel and Stainless Steel Bolting for Low-Temperature Service
ASTM Standards
A194/A194M Specification for Carbon Steel, Alloy Steel, and Stainless Steel Nuts for Bolts for High Pressure or High Temperature Service, or Both
F436/F436M Specification for Hardened Steel Washers Inch and Metric Dimensions
F606/F606M Test Methods for Determining the Mechanical Properties of Externally and Internally Threaded Fasteners, Washers, Direct Tension Indicators, and Rivets
IV. Surface Treatments
- Plating
- Zinc (White / Yellow / Black)
- Cadmium (White / Yellow / Black)
- Zinc Nickel
- Galvanising
- Hot-Dipped Galvanise
- Mechanical Galvanise
- Fluorocarbon Coating
Xylan® / Dupont Coating Systems:
- Xylar 2
- Xylan 1070
- Xylan 1424
- Customised Coating Systems
- Zinc + Fluorocarbon / PTFE coated stud bolt
- Cadmium + Fluorocarbon /PTFE coated stud bolt
- Zinc Nickel + Fluorocarbon /PTFE coated stud bolt
- Zinc Plating + Xylan 1424 Blue PTFE coated stud bolt
- Xylar 2 + Xylan 1070 coated stud bolt
HOW to order our A320 L43 STUD BOLT,ASTM A194 Gr 7 HEX NUTS?
EXAMPLE#1,
3″ 980 mm STUD BOLT&NUTS, A320/A320M-L43, FULL-THREAD, 8-UN, ASME B18.2.1/B1.1 CL.2A/ A194/A194M-7M, WITH TWO HEAVY HEX. NUTS, ASME B18.2.2/B1.1 CL.2B, ZINC BASE COAT, FLUOROPOLYMER COATING, C/W TWO METALLIC WASHERS FLAT TYPE
Audited Supplier 
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