Why is A516 GR.70 so popular for use in pressure vessels?

Pressure vessels store gases or liquids at high pressures. Failure can be catastrophic. A516 Gr. 70 is the material of choice for many such applications because:

1. Safety: Its excellent notch toughness prevents crack propagation. A small flaw won't easily turn into a sudden, brittle fracture.

2. Cost-Effective: It provides an excellent balance of strength, toughness, and fabricability at a reasonable cost compared to higher-alloy steels.

3. Proven Reliability: It has a long history of safe and reliable performance in the industry, making it a trusted and widely accepted material.

Key Properties and Characteristics

Type: Carbon Steel

Key Application: Pressure Vessels

Notch Toughness: This is its most celebrated feature. It is manufactured to have high resistance to brittle fracture, especially at lower service temperatures.

Weldability: It is known for being readily weldable using all common methods without requiring special pre- or post-heating procedures in most thicknesses, which is crucial for fabricating large vessels.

Strength:

Tensile Strength: 70 - 90 ksi (485 - 620 MPa)

Yield Strength: 38 ksi (260 MPa) min.