In this paper,the domestic CT80 coiled tubing is used as the research object. A special welding process is adopted to carry out the pipe and pipe butt welding of the domestic CT80 coiled tubing. Microstructure and microhardness in the heat affected zone of the domestic CT80 welded joints under different cooling rates are compared. The experimental results show that the microstructure of the coarse grain zone is mainly composed of the structure of the ferrite. The grain size of the welded joint is small and the microhardness value is lower in the water cooling condition.
Heat Treatment Technology and Equipment