An Approach to the SCC of Gas Transmission Pipeline

The study on the SCC of gas line pipe is described in detail. This study originates from the two aspects; the H₂S fractional pressure increases as the transfer pressure increases, which presents the SCC problem; the worldwide natural gas demand goes up and many gas fields containing high hydrogen sulfide are been developing, which objectively accelerates this study and the study on the anti-SCC steel. The author considers that the countermeasures against the SCC should be taken in follwing aspects natural gas's sweetening and dewatering; keeping away from the transfer temperature that produces the SCC when operating; the pH of natural gas should be more than 5;increasing the C_th(the minimum hydrogen content)of pipe steel and controlling the Mn and P contents in order to decrease the pipe's segregation.