Steel Grade Datasheet
25CrMo4/ 1.7218 / 4130
Chromium-Molybdenum (Chromoly) Q&T Steel
What is 25CrMo4 (4130) steel?
25CrMo4 (Werkstoff No. 1.7218, equivalent to AISI 4130) is a low-carbon chromium-molybdenum quenched and tempered steel per EN 10083-3 — known worldwide as 'chromoly' (chrome-moly). Its 0.22–0.29% carbon is lower than 42CrMo4, making it more weldable and tougher. In the quenched and tempered (+QT) condition it provides a 450–700 MPa yield and 700–1100 MPa tensile strength — the classic material for aircraft tubing, seamless pressure tube and welded high-strength applications.
Chemical Composition
Cast analysis, % by weight (per the applicable EN standard)
| Element | Range (%) |
|---|---|
| C | 0.22–0.29 |
| Si | ≤ 0.40 |
| Mn | 0.60–0.90 |
| P | ≤ 0.025 |
| S | ≤ 0.035 |
| Cr | 0.90–1.20 |
| Mo | 0.15–0.30 |
Mechanical Properties (+QT)
Values depend on ruling section / thickness (d).
| Section (mm) | Yield Re min (MPa) | Tensile Rm (MPa) | Elongation A min (%) |
|---|---|---|---|
| d ≤ 16 | 700 | 900–1100 | 12 |
| 16 < d ≤ 40 | 600 | 800–950 | 14 |
| 40 < d ≤ 100 | 450 | 700–850 | 15 |
Hardness: +A (annealed): ≤ 241 HB · +QT: typically 250–320 HB. Ideal for thin-wall welded structures.
25CrMo4 / 4130 properties and 4130 vs 4140
International Equivalents
Values marked ≈ are nearest matches, not exact equivalents. Always confirm against the governing standard.
| System | Grade |
|---|---|
| EN | 25CrMo4 |
| W.-Nr. (DIN) | 1.7218 |
| AISI/SAE | 4130 |
| ASTM | A29 / A519 (4130) |
| JIS | SCM430 |
| GOST | ≈ 25ХМ (25KhM) |
| BS (UK) | ≈ CDS110 (1717) |
| GB (China) | ≈ 30CrMo |
Applications
- Aircraft and aerospace fuselage tubing
- Seamless high-pressure tubes
- Roll cages and race chassis
- Chromoly bicycle and motorcycle frames
- Hydraulic cylinders and pistons
- Oil & gas drilling equipment
Available Product Forms
Frequently Asked Questions
What is the difference between 4130 and 4140?+
Both are chromium-molybdenum 'chromoly' steels; the one key difference is carbon: 4130 (0.30%) is lower than 4140 (0.40%). 4130 is tougher and far easier to weld (aircraft, bike frames); 4140 gives higher hardness and strength (shafts, gears, heavy parts). Choose 4130 for thin-wall welded structures, 4140 for high-strength solid parts.
What is chromoly (chrome-moly)?+
'Chromoly' is the common name for steels alloyed with chromium (Cr) and molybdenum (Mo). 25CrMo4/4130 is the classic example. Chromium gives hardenability and wear resistance, molybdenum gives elevated-temperature strength; the result is a weldable steel with a good strength-to-weight ratio.
Is 25CrMo4 weldable?+
Yes, readily — its low carbon makes it much easier than 42CrMo4. Thin-wall tubes (aircraft, bikes) are usually TIG-welded without preheat. Thick sections or critical structures benefit from 150–250 °C preheat and post-weld stress relief.
Is 25CrMo4 the same as AISI 4130?+
For practical purposes yes; 25CrMo4 is the European (EN) and 4130 the American (AISI/SAE) designation, used interchangeably as the same chromium-molybdenum steel. The JIS equivalent is SCM430. For critical work follow the ordering standard's ranges.
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References & Standards
Values on this page are reference data compiled from the applicable EN standard; certified material properties are defined by the mill test certificate (EN 10204 3.1).