A320 L7 Stud Bolts
The low-temperature twin of B7 — same 4140 Cr-Mo steel, same 125 ksi strength, but impact tested at −150 °F for cryogenic and cold-climate service.
Threaded rod inserted through the holes of mating flanges, paired with heavy hex nuts. Available in every diameter and length, imperial and metric, for flanged connections in critical service. Supplied bare or coated, with full material traceability.
ASTM A320 Grade L7 is the alloy-steel bolting grade for low-temperature service. It is made from the same quenched-and-tempered chromium-molybdenum steel as A193 B7 and meets the same strength requirements, with one addition: every heat-treat lot over ½ in. is Charpy impact tested at −150 °F to prove the steel stays tough when it is cold.
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What A320 L7 must meet.
| Nominal diameter (in.) | Tensile strength, min (ksi) | Yield strength 0.2% offset, min (ksi) | Elongation in 2 in., min (%) | Reduction of area, min (%) | Hardness, max |
|---|---|---|---|---|---|
| 2½ and under | 125 | 105 | 16 | 50 | 321 HBW / 35 HRC |
Values per ASTM A320/A320M-26, Tables 1, 2 and 3 (verified against the specification). Confirm the edition called out on your purchase order with our estimating team. Table 1 lists L7 to 2½ in.; footnote A says the limit reflects the sizes commonly available that meet the properties, not an absolute ceiling.
Quenched in liquid and tempered at 1100 °F (593 °C) minimum. Threads are formed after heat treatment where practical (clause 11.1). Charpy impact tested per lot.
Full A320 L7 data sheet: chemistry, physical properties and standards →
Made to standard or to your drawing.
- LNG liquefaction, storage and regasification
- Ethylene and propylene refrigeration loops
- Ammonia and cold-box piping
- Arctic and northern-climate plant flanges
- Cryogenic valves and pumps
- Any A193 B7 application with a low design temperature