Optimization research on welding technology of SMAW

The application of high grade pipeline steels in the construction of oil and gas pipeline had greatly improved the transmission pressure and transmission efficiency and reduced the cost of the construction and operation of the pipeline.However,the weldability of high grade steels was reduced,that the difficulty of controlling the mechanical performance of welded joint was increased.The field welding played a vital role in the oil gas pipeline construction,which was processed in the complex terrain and climate,unstable mechanical load and temperature,and a higher requirement was required to meet the welding performance in this condition.By combination process parameters of the welding current,welding voltage,welding speed in the different weld beads of X70,the optimal welding technology of Shielded Metal Arc Welding(SMAW) was screened that met the requirement of pipe group welding in situ.