Effect of Heat Treatment on ERW Welded Tube

Resistance welding (ERW) is a low-cost, high-efficiency pipeline manufacturing technology, which produces a variety of steel pipe called ERW pipe. ERW welded pipe is made of steel plate or strip after crimping and then welded by high frequency resistance welding. The welded pipe with longitudinal weld has been widely used in oil and natural gas transmission pipeline, oil well casing, coiled tubing and soil (Such as a scaffold).

In recent years, the ERW technology has also been used to produce economical petroleum-grade pipes, partly because of the low cost of ERW technology; on the other hand, the petroleum-made pipes are made of inexpensive carbon steel to reduce pipeline costs. Since the ERW process is a localized heating and pressurizing process, the heat dissipates rapidly along the metal pipe and the crimped steel plate after welding under pressure. The cooling rate can reach the critical cooling rate of the steel. In the ERW pipe, Welding area of its formation of martensite, thus affecting the performance of the welding zone and the performance of the whole pipe is not uniform. Therefore, it is necessary to use post-weld heat treatment to improve the microstructure of the weld zone, so that the microstructure and properties of the welded zone are consistent with the pipe body, to ensure the uniformity of the microstructure and properties of the ERW welded pipe, thereby reducing ERW pipe corrosion environment In the selective corrosion.