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What are SA537 Class 1 and SA516 Grade 70 plates?

SA537 Class 1 and SA516 Grade 70 are two widely used carbon steel pressure‑vessel plates.

ASTM A516 / SA516 plate material is the standard specification for pressure vessel fabrication. ASTM A537 / SA537 plate material is heat-treated, carbon-manganese silicon steel.

ASTM A537 Class 1

A537 Class 1 is normalized, heat treated and displays greater yield and tensile strength that the more common A516 grades. Ideal for Pressure Vessels, Boilers, API 650, and API 620 storage tanks in the Oil & Gas and Petrochemical Industries.

ASTM A516 Gr. 70

A516 Grade 70 plate material is suitable for low temperature application pressure vessels and industrial boilers.

A516 Grade 70 plate material is suitable for lower than ambient temperature applications. A516 Grade 70 offers greater tensile and yield strength than grade 65 and can operate at even lower temperatures. This material is also used extensively for Pipe Shoes, Gussets and Base Plates etc.

• SA537 Cl1: Specified under ASTM A537 / ASME SA‑537 — “Pressure Vessel Plates, Heat‑Treated, Carbon Steel.” Class 1 is intended for pressure vessels and typically requires heat treatment and enhanced toughness controls.
• SA516 Gr70: Specified under ASTM A516 / ASME SA‑516 — “Pressure Vessel Plates, Carbon Steel, for Moderate‑ and Lower‑Temperature Service.” Grade 70 is the most commonly used grade for pressure vessels and boilers.

Chemical Composition Comparison

SA516 Gr 70 has a basic carbon composition with manganese and silicon for deoxidation.

Carbon is 0.27-0.28% max, manganese 0.85-1.20%, phosphorus/sulfur 0.035% max.

SA537 Cl 1 includes silicon (0.15-0.50%) and optional alloys like copper/nickel for better toughness, carbon 0.24% max, manganese 0.70-1.60% (thickness-dependent).

SA537’s silicon enhances low-temp performance.

Comparison table:

Mechanical Properties Comparison

SA516 Gr 70 has yield 38 ksi (260 MPa) min, tensile 70-90 ksi (485-620 MPa).

SA537 Cl 1 offers higher yield 50 ksi (345 MPa) min (≤65mm), tensile 70-90 ksi.

SA537 provides better low-temp toughness with impact testing.

Properties table: