Technical Specifications of A515 Gr 65 Steel Plate for Boiler and Pressure Vessel Applications

Selecting the correct material is critical for boiler and pressure vessel safety and performance. ASTM A515/A515M Grade 65 is a standard specification for carbon steel plates designed specifically for intermediate and higher-temperature service in welded pressure vessels. This guide details the essential technical specifications engineers and procurement specialists need.

Key Technical Specifications

1. Chemical Composition
A515 Gr.65 is a medium-carbon silicon-killed steel. Key element limits (heat analysis) include:

Carbon (C): 0.24% max

Manganese (Mn): 0.90% max (affects strength and hardenability)

Phosphorus (P): 0.035% max

Sulfur (S): 0.035% max

Silicon (Si): 0.15 - 0.40% (provides deoxidation and strength)

This controlled chemistry ensures good weldability and notch toughness at elevated temperatures.

2. Mechanical Properties
The material must meet these minimum requirements:

Tensile Strength: 60,000 - 80,000 psi (415 - 550 MPa)

Yield Strength: 36,000 psi min (250 MPa min)

Elongation: 23% min in 2 inches (50 mm)

3. Thickness Range & Heat Treatment
Plates are typically supplied in the normalized or stress-relieved heat-treated condition to achieve a fine-grain structure and uniform properties. Available thicknesses commonly range from 5 mm to over 200 mm, catering to various vessel diameters and pressure ratings.

Compliance & Application

For boiler and pressure vessel construction, A515 Gr.65 plates must comply with ASME Boiler and Pressure Vessel Code Section II, Part A, where it is designated as SA-515/SA-515M Gr.65. It is ideally suited for furnace shells, boiler shells, and pressure vessel sections operating at intermediate temperatures where post-weld heat treatment (PWHT) is applied.