4142
Data verified4142 is a Cr-Mo steel a touch higher in carbon than 4140, giving slightly higher attainable hardness at the cost of toughness and weldability. Many mills dual-certify 4140/4142 because the windows overlap.
Chemical composition
| Element | Content (%) |
|---|---|
| C | 0.40–0.45 |
| 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 |
Weight percent, per the governing standard ranges. Actual values per heat are on the mill certificate.
Properties
| Hardness (Q&T) | 30–42 HRC typical |
| Tensile strength | 900–1150 MPa (Q&T, typ.) |
| Density | 7.85 g/cm³ |
Heat treatment
Normalize 870 °C; quench 845 °C oil; temper 500–650 °C.
Equivalent grades
| Standard | Designation |
|---|---|
| din | 1.7225 (42CrMo4, near) |
| aisi | 4142 |
| jis | SCM440 (near) |
| gb | 42CrMo (near) |
Compare side by side: 4142 vs 4140 · 4142 vs 42CrMo4
Equivalents overlap in chemistry and use but are not always identical — see our equivalents guide before substituting in certified designs.
Applications & Processing
Applications: Shafts, gears, bolts, drill-string and oilfield parts (non-certified), hydraulic components.
Processing: As 4140, with marginally more care in welding (higher preheat).
FAQ
- Can 4142 replace 4140?
- Usually yes for machined parts: the grades overlap and 4142 meets most 4140 property requirements after the same Q&T cycle. Where a spec names 4140 explicitly, supply dual-certified 4140/4142 material.
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Ask for a quotationVisit NasteelSource: SAE J404 published ranges · Last updated 2026-11-03. Data is indicative — verify critical values against the governing standard and mill certificate before use.