Complete specifications for AISI 4145, a chromium-molybdenum steel widely used for drill collars and high-strength applications in the oil and gas industry.
AISI 4145 low alloy steel containing 0.20% molybdenum is widely used particularly throughout oil patch applications. Similar to 4140 which has a lower carbon level, it has improved hardenability and is more commonly used at higher strength levels.
Larger diameters are often supplied with higher molybdenum level (0.35% max), which may also be used on higher strength variants at smaller diameters. This grade is used extensively for drill collars where high strength and hardenability are critical.
| Element | Min % | Max % |
|---|---|---|
| C | 0.43 | 0.48 |
| Si | 0.15 | 0.35 |
| Mn | 0.75 | 1.00 |
| P | - | 0.035 |
| S | - | 0.040 |
| Cr | 0.80 | 1.10 |
| Mo | 0.15 | 0.25* |
| Fe | Balance | Balance |
*Large diameters may use 0.25-0.35% Mo
| Grade | Molybdenum % | Applications | Hardenability |
|---|---|---|---|
| Standard Grade | 0.15-0.25% | General applications, smaller sections | Standard depth hardening |
| High Moly Grade | 0.25-0.35% | Large diameters, high strength requirements | Enhanced hardenability for thick sections |
Superior hardenability and strength for demanding drilling operations
Excellent strength and hardenability for large section sizes
Outstanding impact resistance and durability under heavy loads
Lower carbon content for better weldability but reduced strength vs 4145
Nickel addition provides better hardenability and toughness than 4145
Lower carbon and strength but superior weldability compared to 4145
Nickel-chromium-molybdenum steel with different chemistry than 4145
Get competitive pricing on high-quality AISI 4145 steel with complete material certifications, heat treatment services, and drill collar specifications.