EFW Pipe Manufacturing, Processing of Electric Fusion Welding

--An In-Depth Guide to Large-Diameter Pipe Welding and Quality Control

Discover EFW pipe manufacturing processes. Learn how automated PAW+GTAW welding and ASTM A358 standards ensure safety for large-diameter piping systems.

EFW (electrofusion welded) pipe plays a crucial role in large-diameter, heavily corrosive, and high-pressure industrial piping systems. This article provides an in-depth analysis of the forming and welding manufacturing process of EFW pipes, helping purchasing and engineering personnel accurately assess their application value under harsh operating conditions.

Core Manufacturing Steps of EFW Pipes

Steel Plate Forming: High-quality hot-rolled steel plates, after undergoing secondary spectroscopic inspection (PMI), are pressed into high-precision round tube blanks using roll forming (RBE) or CNC continuous bending technology.

Automated Combined Welding: This is the core step of the EFW process. Plasma welding (PAW) is typically used for the root pass to ensure full penetration, followed by tungsten inert gas welding (GTAW) for the cap pass. This fully automated combined welding process significantly improves welding efficiency and ensures a full weld with stable mechanical properties.

Deep Heat Treatment: The overall solution annealing treatment after welding is a key step in eliminating processing stress and restoring the original corrosion resistance of austenitic or duplex stainless steel.

Stringent Quality Inspection and Standards

Radiological Testing: High-specification EFW welds undergo 100% X-ray inspection (RT) according to relevant production standards such as ASTM A358 or ASTM A671 to accurately detect hidden internal defects such as porosity and lack of fusion.

Hydraulic Pressure Testing: Each pipe is individually verified for its sealing performance and overall structural strength under extreme working pressure.

Thanks to the flexibility of large-diameter manufacturing, EFW welded pipes are widely used in main process pipelines of petrochemical refineries, fluid transportation on offshore platforms, and seawater desalination systems, perfectly overcoming the limitations of high production costs associated with large-diameter seamless pipes.

MTSCO's HUXIN plant, with 35 years of pipe manufacturing experience, provides you with top-tier EFW welded pipe solutions. We utilize advanced PAW and GTAW fully automated welding technology to overcome the challenge of non-circular welds in large-diameter welded pipes. Combined with a 12-meter large annealing furnace and 100% X-ray inspection, MTSCO can customize high-quality welded pipes with outer diameters up to 3 meters. All products are ISO and PED certified, ensuring your engineering projects achieve high cost-effectiveness and ultimate safety.