ASTM A320 Grade L7 Stud Bolt, Grade L7 Bolts, ASTM A320 Gr L7 Studs, ASTM A320 Grade L7 Threaded Rod Suplier in Mumbai, India.
Standard Specification for Alloy-Steel and Stainless Steel Bolting for Low-Temperature Service
This is the most common A320 bolt grade. A320 Grade L7 bolts, stud bolts, stud and threaded rod are manufactured from alloy steel with chromium, manganese, and molybdenum. The bolts undergo a heat treating process to reach their required mechanical properties. L7 threaded studs and short, headed bolts are readily available in the marketplace. These bolts are typically bought and sold in a plain, bare metal finish. L7 bolts are available through 2-1/2” in diameter. A320 Grade L7 bolts larger than 1/2″ diameter require a Charpy impact test.
Bolting A320 Grade L7
| L7 Alloy steel |
AISI 4140/4142 Quenched and tempered |
ASTM A320 Grade L7 Chemical Composition
| Element |
L7 (AISI 4140) |
| Carbon |
0.38 - 0.48% |
| Manganese |
0.75 - 1.00% |
| Phosphorus, max |
0.035% |
| Sulfur, max |
0.040% |
| Silicon |
0.15 - 0.35% |
| Chromium |
0.80 - 1.10% |
| Nickel |
|
| Molybdenum |
0.15 - 0.25% |
ASTM A320 Grade L7 Mechanical Properties
| Grade |
Diameter |
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 |
A320 Grade L7 Recommended Hardware
| Grade |
Nuts |
Washers |
| L7 |
A194 Grade 4 or 7 |
F436 |