1040
Data verified1040 is a medium carbon steel for moderately stressed shafts, bolts and gears. It is the plain-carbon predecessor of 5140/40Cr in many cost-sensitive designs, with similar carbon but no chromium hardenability boost.
Chemical composition
| Element | Content (%) |
|---|---|
| C | 0.37–0.44 |
| Mn | 0.60–0.90 |
| P | ≤0.040 |
| S | ≤0.050 |
Weight percent, per the governing standard ranges. Actual values per heat are on the mill certificate.
Properties
| Tensile strength | 570–660 MPa (normalized, typ.) |
| Density | 7.85 g/cm³ |
Heat treatment
Normalize 850–870 °C; quench 840–860 °C water/oil; temper 450–620 °C.
Equivalent grades
| Standard | Designation |
|---|---|
| din | 1.0511 (C40) |
| aisi | 1040 |
| jis | S40C |
| gb | 40 |
Compare side by side: 1040 vs 1045 · 1040 vs 5140
Equivalents overlap in chemistry and use but are not always identical — see our equivalents guide before substituting in certified designs.
Applications & Processing
Applications: Shafts, crankshafts (light), bolts, gears, tie rods.
Processing: Machines well normalized; induction hardening common; weld with preheat.
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Ask for a quotationVisit NasteelSource: SAE J403 published ranges · Last updated 2026-11-03. Data is indicative — verify critical values against the governing standard and mill certificate before use.