Steel Plate Grades: Α36, A572, A514 and AR400 Comparison

Steel Plate Grades: Α36, A572, A514 and AR400 Comparison

Steel plate comes in dozens of grades, but the four that cover 90% of structural and industrial applications are A36, A572, A514 and AR400. Each is optimized for a different job: general structure, high-strength structure, high-yield pressure vessels, and abrasion resistance. This guide compares the four grades so you can specify the right plate without over-spending or under-designing.

The Four Grades at a Glance

A36 is the standard mild structural plate — 250 Απόδοση MPa, δυνάμενος να συγκολληθεί, cheap, used for general building frames, brackets and base plates. A572 Grade 50 is the high-strength low-alloy (HSLA) version — 345 Απόδοση MPa, used when you need less weight or higher load capacity. A514 is the quenched and tempered high-yield grade — 690 Απόδοση MPa, used for cranes, heavy equipment and pressure vessels. AR400 is the abrasion-resistant grade — 1000+ BHN hardness, used for liners, buckets and wear surfaces. Δείτε το δικό μας Επίπεδη μπάρα Q235B.

Α36: The Workhorse

A36 is the most common structural steel plate in the world. It has a minimum yield of 250 MPa, welds easily without preheat, machines cleanly, and is the cheapest structural grade. It is used for building frames, bridge girders, πλάκες βάσης, αγκύλες, and any application where load is moderate and cost matters. A36 is available in thicknesses from 3 mm έως 200 mm, and it is the default choice when no other grade is specified. It is equivalent to Chinese Q235B and European S235JR.

A572 Gr.50: High-Strength Low-Alloy

A572 Grade 50 has a minimum yield of 345 MPa — 38% stronger than A36. It is used when you need to reduce weight or increase span: bridge girders, building columns, κουφώματα φορτηγών, and transmission towers. Because it is stronger, you can use thinner plate, which reduces total weight and cost. A572 Gr.50 costs about 15% more than A36 per kilogram, but the thinner section often makes the total part cheaper. It is weldable with standard processes, but preheat is required for thicknesses over 25 mm. It is equivalent to Q355B and S355JR.

A514: Quenched and Tempered

A514 is a high-strength alloy plate that is quenched and tempered to achieve 690 MPa yield — nearly 3× A36. It is used for crane booms, heavy equipment frames, δοχεία πίεσης, and military vehicles where weight must be minimized while carrying high loads. A514 costs 3 – 4× A36, and it must be welded with low-hydrogen electrodes and preheated to 150°C. It is not a general-purpose grade — use it only when the strength is required by calculation.

AR400: Ανθεκτικό στην τριβή

AR400 is not a structural grade — it is a wear-resistant plate with a hardness of 370 – 425 BHN. It is used for crusher liners, excavator buckets, dump truck beds, and any surface that slides against rock or gravel. AR400 does not yield in the traditional sense — it is hard and brittle. It cannot be welded to structural members without preheat and post-heat, and it cannot be bent. It is a specialty wear material, not a structural steel. Specify it only for wear surfaces.

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