R ＆ D Achievement of X120 SAWH Pipe and Relevant Analysis

The X120 steel linepipe is regarded so far as the linepipe in the most premium steel grade in the world.Elaborated here in the article is the achievement from the R & D activities for the X120 SAWH pipe as performed by North China Petroleum Steel Pipe Co.,Ltd.Relevant metallographic structure analyses and tests demonstrate that the X120 SAWH pipe as developed is in conformity to the requirements as specified under API Spec 5L(the 44th edition),and features high safety level,nevertheless its yield strength is rather high,and its charpy impact value rather low.Addressing the existing shortcomings,corrective actions are proposed,including reducing the yield strength of the strip steel,increasing the coiling temperature,and properly cutting down the contents of the alloy elements B,Mo and Ni and the carbon equivalent in the steel,etc.