A572 Grade 50 steel equivalents
A572 Grade 50 steel is nearest to EN 1.0045 (S355JR), JIS SM490A and China GB Q355B. These are nearest equivalents, not identical grades: the governing standard or mill certificate decides.
- AISI / ASTM / SAE US
- A572 Gr 50
- EN steel number EN 10027-2
- 1.0045
- EN steel name EN 10027-1
- S355JR
- JIS Japan
- SM490A
- GB China
- Q355B
- Family
- High-strength low-alloy structural steel
About A572 Gr 50
High-strength low-alloy structural steel. General characteristics; check the standard and the supplier for anything critical.
What it is
A high-strength low-alloy structural steel. It is stronger than A36 and is weldable, used where weight saving matters. Equivalents differ in specified strength and toughness tests, so check before substituting.
Typical uses
Bridges, building columns and beams, crane and heavy equipment frames, trailers and towers.
Machining notes
Similar to A36, slightly tougher. Remove mill scale before precision work.
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 A572 Grade 50 steel?
The nearest EN grade is 1.0045, steel name S355JR.
What is the JIS equivalent of A572 Grade 50 steel?
The nearest Japanese grade is SM490A.
What is the Chinese GB equivalent of A572 Grade 50 steel?
The nearest Chinese GB grade is Q355B.
Is 1.0045 the same as A572 Gr 50?
1.0045 (S355JR) is the nearest European equivalent of A572 Gr 50, 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 A572 Gr 50 used for?
Bridges, building columns and beams, crane and heavy equipment frames, trailers and towers.