Technical specifications and scope of application for ASTM/ASME A/SA 691 pipes
The ASTM/ASME A/SA 691 specification governs the production of electric-fusion-welded steel pipes manufactured using filler metal. The raw materials used are alloy steel plates with specified chemical composition and strength characteristics. This type of tubular product, supplied by EV Group China, is optimized for use in critical components of energy and petrochemical equipment subjected to high pressures and temperatures.
The production process may or may not include an additional heat treatment stage, depending on the target class of the product and customer requirements for performance properties. If necessary, EV Group China ensures additional testing and verification studies are conducted in accordance with the specification.
The standard covers pipes with a nominal outside diameter of 400 mm (16 inches) and a wall thickness of up to 75 mm (3 inches). The supply of products with other geometric parameters is permitted, provided that all regulatory requirements of the standard are fully met.
Classification and marking of products
The classification system in the A691 standard is based on two key factors: the chemical composition of the source steel plate and the type of heat treatment performed. The product class designation determines:
- The type of steel plate used.
- Heat treatment parameters of the pipe during the production process.
- The requirement for radiographic control of the welded joint.
- Completion of hydraulic pressure testing.
Important note: when selecting material for specific operating conditions, it is necessary to consider the temperature regime of the equipment, guided by the principles set forth in the A20/A20M standard.
EV Group China notes that the values stated in the SI system and the inch-pound system are separate standards. When designing systems, one system of measurement should be used, as combining them may lead to technical inconsistencies.