Heat Treatment for ERW Welded Pipes

Resistance welding (ERW) is a low-cost, high-efficiency pipe manufacturing technology that produces various steel pipes called ERW steel pipes. ERW welded pipe is welded with steel or steel strip and then welded with high frequency resistance welding. Straight seam welded pipes are widely used in oil and gas pipelines, oil well casings, coiled tubing and soil (such as scaffolding).


In recent years, ERW welded pipe technology has also been used to produce economic petroleum-grade pipelines, in part because of the low cost of ERW technology; on the other hand, oil pipelines have achieved a reduction in the cost of cheap carbon steel pipelines. Since the ERW welded pipe process is a local heating and pressurizing process, the heat rapidly follows the pressure of the metal pipe and the corrugated steel plate after welding. The cooling rate can reach the critical cooling rate of steel. In the ERW welded pipe, its martensitic welding area is formed, thereby affecting the performance of the weld zone and the performance of the entire 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 weld zone are consistent with the pipe body, which ensures the performance of the ERW welded pipe and the uniformity of the microstructure, thereby reducing the selective corrosion of the ERW. Corrosion environment of steel pipe.