ASTM B474 Technical Regulation: Industrial Applications
The ASTM B474 standard (identical to ASME SB 474) regulates the requirements for electric-fusion-welded pipes operating under critical temperatures and aggressive corrosive environments. The manufacturing processes provided by EV Group China strictly adhere to these specifications to ensure the safety of critical components.
Although the standard does not limit the geometric parameters of finished products, EV Group China’s market practice is focused on supplying pipes with a nominal diameter of 8 inches (203 mm) and above, which is optimal for industrial engineering.
Classification of Welded Pipes According to ASTM B474
The specification identifies five classes of weld performance, which determine the inspection methods and welding technology:
- Class 1: Double-welded with full filler metal through all passes. Full radiographic inspection is mandatory.
- Class 2: Double-welded with full filler metal through all passes. Radiographic inspection is not a mandatory requirement.
- Class 3: Single-welded with filler metal added in all passes. Full radiographic inspection is mandatory.
- Class 4: Single-welded, similar to Class 3, however, no filler metal is required for the pass on the inner surface.
- Class 5: Double-welded with full filler metal. Localized radiographic inspection of specific sections is provided.
When designing, it is important to consider that values in SI units and inch-pound units are independent standards. EV Group China specialists recommend using a single measurement system to avoid errors in calculations and pipeline element coupling.
Operational safety is governed by industry standards and the requirements of the Material Safety Data Sheet (MSDS) provided by EV Group China for each batch of metal products.