4140 steel equivalents
4140 steel is nearest to EN 1.7225 (42CrMo4), JIS SCM440 and China GB 42CrMo. These are nearest equivalents, not identical grades: the governing standard or mill certificate decides.
- AISI / ASTM / SAE US
- 4140
- EN steel number EN 10027-2
- 1.7225
- EN steel name EN 10027-1
- 42CrMo4
- JIS Japan
- SCM440
- GB China
- 42CrMo
- Family
- Chromium-molybdenum alloy steel
About 4140
Chromium-molybdenum alloy steel. General characteristics; check the standard and the supplier for anything critical.
What it is
A medium-carbon chromium-molybdenum alloy steel. It through-hardens in moderate sections and is tough after quenching and tempering. It is widely sold pre-hardened, ready to machine.
Typical uses
Shafts, spindles, gears, axles, tool holders, fixtures, die shoes and high-strength studs and bolts.
Machining notes
Machines well annealed. Pre-hardened bar machines with carbide at reduced speed. Welding needs preheat and post-weld heat treatment.
Related grades
Grades people often compare with this one.
Fasteners and tapping
Bolts made from this steel
A bolt's property class comes from heat treatment and testing to ISO 898-1 or SAE J429, not from the steel grade alone. A part made from this steel is not automatically equivalent to class 8.8, 10.9 or 12.9, or to grade 5 or 8.
Bolt torque chartTap drills
For mild and alloy steel, 65–75 % thread is the usual target. The tap drill chart lists the standard drill and the thread percentage it leaves for every size.
Tap drill chartAll carbon and alloy steel grades
Nearest equivalents across the five designation systems.
| AISI / ASTM | EN name | EN number | JIS | China GB |
|---|---|---|---|---|
| 1020 | C22 | 1.0402 | S20C | 20 |
| 1045 | C45 | 1.0503 | S45C | 45 |
| 4130 | 25CrMo4 | 1.7218 | SCM430 | 30CrMo |
| 4140 | 42CrMo4 | 1.7225 | SCM440 | 42CrMo |
| 8620 | 20NiCrMo2-2 | 1.6523 | SNCM220 | 20CrNiMo |
| 52100 | 100Cr6 | 1.3505 | SUJ2 | GCr15 |
| A36 | S235JR | 1.0038 | SS400 | Q235B |
| A572 Gr 50 | S355JR | 1.0045 | SM490A | Q355B |
Common questions
What is the European equivalent of 4140 steel?
The nearest EN grade is 1.7225, steel name 42CrMo4.
What is the JIS equivalent of 4140 steel?
The nearest Japanese grade is SCM440.
What is the Chinese GB equivalent of 4140 steel?
The nearest Chinese GB grade is 42CrMo.
Is 1.7225 the same as 4140?
1.7225 (42CrMo4) is the nearest European equivalent of 4140, not an identical grade. Composition limits and required properties differ in detail, so check the governing standard or the mill certificate when it matters.
What is 4140 used for?
Shafts, spindles, gears, axles, tool holders, fixtures, die shoes and high-strength studs and bolts.