1045 steel equivalents
1045 steel is nearest to EN 1.0503 (C45), JIS S45C and China GB 45. These are nearest equivalents, not identical grades: the governing standard or mill certificate decides.
- AISI / ASTM / SAE US
- 1045
- EN steel number EN 10027-2
- 1.0503
- EN steel name EN 10027-1
- C45
- JIS Japan
- S45C
- GB China
- 45
- Family
- Medium-carbon steel
About 1045
Medium-carbon steel. General characteristics; check the standard and the supplier for anything critical.
What it is
A medium-carbon plain carbon steel. It is stronger than 1020 and responds to flame or induction hardening for a hard, wear-resistant surface.
Typical uses
Shafts, axles, spindles, gears, studs, couplings and general machine parts.
Machining notes
Good machinability, especially normalised or cold drawn. Welding needs preheat and controlled cooling because of the higher carbon.
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 1045 steel?
The nearest EN grade is 1.0503, steel name C45.
What is the JIS equivalent of 1045 steel?
The nearest Japanese grade is S45C.
What is the Chinese GB equivalent of 1045 steel?
The nearest Chinese GB grade is 45.
Is 1.0503 the same as 1045?
1.0503 (C45) is the nearest European equivalent of 1045, 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 1045 used for?
Shafts, axles, spindles, gears, studs, couplings and general machine parts.