ASTM A320 L7 is manufactured from AISI 4140 base material and is supplied in a quenched and tempered condition. Due to the impact requirements at low temperatures, it is mainly used in a low-temperature environment or application, predominantly but not exclusively up to 2 ½” in diameter.
Lonestar can offer this material in a standard condition, or it can be provided with supplementary testing as defined in ASTM A320. This material can also be offered fully in compliance to the additional requirements of API 20E BSL 1, 2 and 3.
ASTM A320 L7: Forms
| LoneStar Manufacture | ||
| Stud Bolts | ✓ | |
| Studding | ✓ | |
| Hexagon Headed Bolting | ✓ | |
| Socket Headed Bolting | ✓ | |
| Double Ended and Waisted Studs | ✓ | |
| Associated OEM Parts | ✓ |
ASTM A320 L7: Sizes and Threads
| LoneStar Manufacture | ||
| Metric Coarse | ✓ | |
| Metric Fine | ✓ | |
| Imperial UNC | ✓ | |
| Imperial 8UN | ✓ | |
| Imperial UNF | ✓ | |
| ACME | ✓ | |
| Metric sizes available | Up to M100 | |
| Imperial sizes available | Up to 6.00″ |
ASTM A320 L7: Chemical Composition
| Carbon | 0.38-0.48 | % |
| Manganese | 0.75-1.00 | % |
| Phosphorus | 0.035 | % Max |
| Sulphur | 0.040 | % Max |
| Silicon | 0.15-0.35 | % |
| Chromium | 0.80-1.10 | % |
| Nickel | – | … |
| Molybdenum | 0.15-0.25 | % |
| Copper | – | … |
| Niobium | – | … |
| Titanium | – | … |
| Vanadium | – | … |
| Aluminium | – | … |
| Nitrogen | – | … |
ASTM A320 L7: Mechanical Properties
| 2.1/2″ and under | Over 2.1/2″ to 4″ | Over 4” | |
| Tensile Strength Min, Ksi (MPa) | 125 (860) | 110 | 100 |
| Yield Strength min, 0.2% offset Ksi (MPa) | 105 | 95 | 85 |
| Elongation in min% | 18 | 17 | 16 |
| Reduction of Area min% | 50 | 45 | 45 |
| Hardness Max | 321 HBW | 321 HBW | 321 HBW |
| Hardness Max | 35 HRC | 35 HRC | 35 HRC |
ASTM A320 L7: Impact Properties
| Test Temperature °F (°C) | -150 (-101) | |
| Average impact toughness, min, ft-lbf (J) | 20 (27) | |
| Average impact toughness, min, ft-lbf (J) | 15 (20) |
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