Influence of Heat Treatment on ERW Welded Pipe

Resistance Welding (ERW) is a low-cost, high-efficiency pipe manufacturing technology whereby various technically produced steel pipelines are called ERW pipe. ERW pipe is made of steel plate or strip after the high-frequency resistance after welding and resistance welded steel pipe, which has a longitudinal weld pipe has been widely used in oil and gas pipelines, casing, coiled tubing and soil Cheng parts (such as scaffolding).

In recent years, ERW technology has also been used to produce economical oil access tubes, on the one hand from the low cost of ERW technology; on the other hand, this oil access tube has been made from inexpensive carbon steel to reduce pipeline costs. Due to the ERW process is a local heating and pressure forming method, under pressure after welding forming, the rapid loss of heat along the metal pipe and curly forming steel, the cooling rate can often reach the critical cooling rate of steel in the ERW pipe. The formation of martensite welding zone, thus affecting the performance of the welding zone and the entire pipe performance is not uniform. Therefore, it is necessary to use post-weld heat treatment to improve the microstructure of the weld zone so that the weld zone has the same microstructure and performance as the pipe body, ensuring the uniform microstructure and properties of the ERW pipe, thus alleviating the corrosion of the ERW pipe in the corrosive environment selective erosion.