AISI 4140 L80 Alloy Steel
Introduce
AISI 4140 80K, PSL 3, API 5CT Standards, NACE MR0175:2015
Chemical Composition
| Grade | C | Mn | Cr | Mo | Si | P | S | Ni | Cu | V | H max. ppm |
| Min. | 0.380 | 0.750 | 0.800 | 0.150 | 0.150 | – | – | – | – | – | – |
| Max. | 0.430 | 1.000 | 1.100 | 0.250 | 0.350 | 0.025 | 0.025 | 0.250 | 0.300 | 0.300 | 2.000 |
Heat Treatment
| Austenizing temperature | Time | Tempering temperature | Time |
| 1600 ±25℉ (871 ±14℃) | Min. 60 minutes | 1250 ±50℉ (677 ±27℃) | Min. 60 minutes |
Oil or Polymer or Water. For Water Quenching, the temperature of water shall not exceed 38℃ (100℉) at start of quench. For bath-type quenching, the temperature of water shall not exceed 49℃(120℉) at any time during the quench cycle.
Mechanical Properties
as per ASTM A370 -20
| Yield strength
| Tensile strength minimum | Elongation in 2” (minimum) | Reduction Area (minimum) |
| Min. 80,000 psi (552 MPa) Max. 95,000 psi (655 MPa) | 100,000 psi (690 MPa) | 18% | 35% |
Quality Inspection
- Specimen test location & QTC
- Charpy V-notch impact at 21℃ / -32℃ / -60℃
- Hardness as per ASTM E10-18: On surface / 1”below surface
- Volumetric NDE 100% – Ultrasonic
- Minimum hot work reduction ratio 4.0 to 1
- Grain size should be #S or Finer as per ASTM E112 – 13
- Surface inspection
