How to improve the high frequency weld toughness steel tube technology is a major problem. In mass production practice based on analysis of the impact of ERW steel pipes Eimpact toughness of a variety of factors. That in order to further improve the impact toughness of the weld, to meet long pipeline steel pipe for high toughness proposed training requirements, the need to start from the quality control of raw materials, steel coils, combined with manufacturing processes, enhance forming, welding and post weld heat treatment line for quality control .
Frequency tube welding process is the use of high-frequency current generated by the skin should principle the back edge of the hot-rolled coil was heated to a molten state, and then by mechanical extrusion welding. Through the process of its production of steel pipe weld fusion center will be a white line, fusion line both sides of the heat affected zone will produce from the central to the direction of extension and external surfaces of the metal flow lines.
As is the use of high frequency welding tube material as the base material, so the performance of the weld and base metal significant performance relationship. In ordinary materials, weld and base metal ductile-brittle transition temperature curve. In general the material, the base metal and weld Charpy impact test values of absorbed energy difference is small. In contrast, in high toughness materials, there are large differences in impact toughness was significantly inferior to the base material, but significantly better than ordinary materials welds. From this high impact toughness weld center tube generally lower than the impact toughness of the base metal, even with the ductile material, although the toughness of the weld is improved, but not completely improved impact toughness of weld center.
No comments:
Post a Comment