Effects of Welding Methods on Corrosion Resistance of Welding Joint of X65Pipeline Steel

摘要

In view of severe corrosion of welding joint of pipeline steel used for oilrntransportation, the welding joints of X65 pipeline steel formed by two differentrnwelding processes, plasma arc welding (PAW) and TIG welding used for backingrnwelding and MIG welding for subsequent filling welding, were compared in terms ofrnthe microstructure, the hardness and the corrosion resistance with the welding jointsrnformed by submerged arc welding(SAW). The results show that the microstructurernof the PAW joint is finer and more uniform than those made by the other weldingrnmethods; The hardness of all the three kinds of welding joints can meet the NACErncriteria. The results acquired from the electrochemical experiment and the test ofrnsulfide induced stress corrosion cracking (SSCC) show that the PAW joint has thernbest corrosion resistance.