L43Stud bolt
ASTM A320 Grade L43
L7 runs out at 2½ in. L43 uses nickel-alloyed 4340, which hardens right through a thicker section, so the same 860 MPa and the same −101 °C impact requirement hold all the way to 4 in.
- Base material
- Nickel-chromium-molybdenum alloy steel (AISI 4340)
- Heat treatment condition
- Quenched and tempered at 593 °C minimum
- Hardness, max
- 321 HBW / 35 HRC maximum
Service temperature
-101 °C+427 °C−273+900 °C
Specified on large cryogenic flanges — LNG loading arms, cold boxes and ethylene plant headers above 2½ in.
Chemical composition
| Element | Min (% by weight) | Max (% by weight) |
|---|---|---|
| C | 0.38 | 0.43 |
| Mn | 0.60 | 0.80 |
| P | — | 0.035 |
| S | — | 0.040 |
| Si | 0.15 | 0.35 |
| Ni | 1.65 | 2.00 |
| Cr | 0.70 | 0.90 |
| Mo | 0.20 | 0.30 |
Mechanical properties
| Diameter | Tensile strength, min | Yield strength, min | Elongation, min | Reduction of area, min |
|---|---|---|---|---|
| ≤ 4 in (≤ M100) | 860 MPa (125 ksi) | 725 MPa (105 ksi) | 16 % | 50 % |
Charpy V-notch impact
Charpy V-notch at −101 °C: 27 J average of three specimens, 20 J minimum on any one specimen.
Matching nuts
Recommended coatings
Equivalent grades
- AISI 4340
- EN 34CrNiMo6 / 1.6582
- JIS SNCM439
Need a quotation?
Send us the grade, size and quantity. We reply within one working day with price, lead time and the certificate package included.