25CrMo4 Chromoly Tubing
25CrMo4 is the European chromium-molybdenum steel closest to 4130. European tube standards describe its delivery condition with a system of plus-symbols that buyers used to American terms need to translate.
Decoding the 25CrMo4 Designation
The EN designation system for structural and engineering steels encodes alloy information as follows:
- '25': approximate nominal carbon content in hundredths of a percent (0.25%)
- 'Cr': chromium alloying addition
- 'Mo': molybdenum alloying addition
- '4': multiplied by 4 gives the approximate chromium percentage (4 × 0.25 = 1.0%)
This differs from the AISI '4130' where '30' indicates 0.30% nominal carbon. The minor carbon nominal difference between 25CrMo4 (~0.25% nominal) and 4130 (~0.30% nominal) is one reason the two designations are not perfectly interchangeable without specification comparison.
EN Standards for 25CrMo4 Tubing
Seamless 25CrMo4 mechanical tubing in Europe is governed primarily by EN 10297 (Seamless Circular Steel Tubes for Mechanical and General Engineering Purposes). For heat-treatable alloy steels, EN 10083 provides the composition and mechanical property requirements. The material is supplied in conditions denoted by + codes: +A (annealed), +N (normalized), +QT (quenched and tempered).
| Parameter | 25CrMo4 (EN) — Reference |
|---|---|
| EN designation | 25CrMo4 |
| Material number | 1.7218 |
| Tubing standard | EN 10297 |
| Steel standard | EN 10083 |
| Condition codes | +A (Annealed), +N (Normalized), +QT (Q&T) |
| North American equivalent | AISI/SAE 4130 (close — not identical limits) |
| Supply form (verified) | Seamless tubing |
| MTC available | EN 10204 3.1 |
EN Delivery Conditions Explained
In European standards the condition follows the grade name after a plus sign. The symbols most often seen on 25CrMo4 tube are:
| EN symbol | Meaning | Nearest American term |
|---|---|---|
| +C | Cold drawn, no final heat treatment | As-drawn, hard |
| +LC | Cold drawn with a light final pass | Soft drawn |
| +SR | Cold drawn and stress relieved | Stress relieved |
| +A | Annealed | Annealed |
| +N | Normalized | Normalized |
| +QT | Quenched and tempered | Quenched and tempered |
An order for European tube therefore reads along the lines of: seamless precision tube, 25CrMo4 +N, 40 × 2 mm, with a 3.1 certificate. If your drawing calls for the American grade instead, see 4130 chromoly tubing. The relationship between the two is covered on 4130 vs 25CrMo4 and EN 25CrMo4 tubing.
Frequently Asked Questions
Can I use 25CrMo4 tubing where AISI 4130 is specified?
These grades are close equivalents. However, a direct substitution in safety-critical applications requires a formal engineering comparison of the actual ladle analysis against the specified material's composition limits. Do not substitute without responsible engineer approval.
Is '25CrMo4 chromoly' a redundant term?
Not exactly redundant — '25CrMo4' is the technical designation; 'chromoly' is the informal descriptor for the Cr-Mo alloy family. Together they help buyers who know the informal term but need to confirm the EN designation.
What does +N mean after 25CrMo4?
The tube is supplied in the normalized condition.
Is 25CrMo4 tube sized in inches or millimetres?
European standards use metric dimensions.
What does +QT mean?
Quenched and tempered.
Source 25CrMo4 Chromoly Tubing
Specify your EN designation, product standard, metric dimensions, condition, and MTC requirements.
- Grade: 25CrMo4 / 1.7218
- Standard (EN 10297)
- OD and Wall in mm
- Condition
- Quantity
- MTC 3.1
- Delivery Location