Steel Plate Thickness Guide: From 1/4 Inch to 12 Inch
3766Learn standard steel plate thicknesses from 1/4” to 12”, conversion to mm, typical applications, and weight reference for construction and industrial projects.
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For global buyers, ASTM A572 steel represents a versatile, cost-efficient structural material used across bridges, buildings, machinery, and fabrication industries. It combines high strength, good weldability, and low weight, making it a preferred choice for small and mid-sized fabricators and stockists serving structural steel markets.
Unlike generic mild steels, A572 Grades 42–65 offer flexibility for different mechanical requirements — and understanding these differences helps you make smarter purchasing decisions.
As a global supplier, CJM Steel works closely with distributors and project buyers to match A572 grades with their regional equivalents and performance needs.

The A572 grades—including Gr.42, Gr.50, Gr.55, Gr.60, and Gr.65—offer a balanced combination of strength and weldability, giving buyers flexibility across multiple structural applications.
| Grade | Yield Strength (MPa) | Tensile Strength (MPa) | Typical Application | Procurement Insight |
|---|---|---|---|---|
| A572 Gr.42 | 290 | 415 | General structures, low-stress fabrication | Suitable for small fabricators replacing A36 with higher strength. |
| A572 Gr.50 | 345 | 450–620 | Beams, columns, plates, bridges | The most common global grade. S355JR and Q345B are interchangeable in most applications. |
| A572 Gr.55 | 380 | 485–620 | Machinery parts, offshore structures | Limited availability; ensure consistent heat numbers when mixing batches. |
| A572 Gr.60 | 415 | 485–650 | Heavy structural beams, wind tower parts | Ideal where Gr.50 may be insufficient but Gr.65 is excessive. |
| A572 Gr.65 | 450 | 485–655 | High-load bridges, cranes | S460N is a close match but may require additional testing for critical projects. |
The mechanical properties of A572 steels vary slightly between grades but share a common design target: high yield-to-weight ratio and consistent performance in welding and forming.
| Grade | C (%) | Mn (%) | Si (%) | P max (%) | S max (%) |
|---|---|---|---|---|---|
| A572 Gr.50 | 0.23 | 1.35 | 0.40 | 0.040 | 0.050 |
| A572 Gr.60 | 0.26 | 1.50 | 0.40 | 0.040 | 0.050 |
| A572 Gr.65 | 0.26 | 1.65 | 0.40 | 0.040 | 0.050 |
*Composition for Gr.42 and Gr.55 not shown; Gr.42 has lower C/Mn, Gr.55 is intermediate. Full data available upon request.*
While technical equivalence is important, smart sourcing requires more than just matching standards. The table below adds Procurement Insight—a quick expert note for traders and fabricators deciding which international grades to source.
| ASTM | EN | JIS | IS | Procurement Insight |
|---|---|---|---|---|
| A572 Gr.42 | S275JR | SM400A | IS 2062 E250 | Ideal entry-level replacement for mild structural grades. |
| A572 Gr.50 | S355JR / Q345B | SM490A | IS 2062 E350 | Most popular for export projects; global stock availability. |
| A572 Gr.60 | S420N | SM490YA | IS 2062 E410 | Use when higher yield strength is needed for structural beams. |
| A572 Gr.65 | S460N | SM490YB | IS 2062 E450 | Check project specifications before substitution — close but not identical. |
A572 steels are widely used in:
If you’re sourcing for cut-to-size plates or coils, check our dedicated pages:

Whether you’re a stockist, trading company, or processing workshop, A572 steels provide flexibility for multi-market distribution.
At CJM Steel, we maintain regular stock for A572 Gr.50 / S355JR, with custom rolling available for higher grades like Gr.60 and Gr.65. Our team helps clients match regional equivalents (EN, IS, JIS) and ensures smooth compliance with project specifications.
For buyers, the key isn’t only the numbers — it’s knowing which grade fits your cost, certification, and project performance goals.
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