Study on Corrosion Behavior of 20# Seamless Steel Pipeline in High Sulfur Environment

Abstract

The corrosion behavior of 20# seamless steel pipe in the high-sulfur gas well of the fifth gas production plant with Petro China Changqing was investigated. The 20# seamless pipe with 159 × 7 mm was buried underground with 1 m in November 2013. The methods of scanning electron microscope (SEM), microhardness and X-ray diffraction (XRD) were used to evaluated the corrosion behavior of 20# seamless pipe. The microhardness of the pipe is 228 HV, yield strength is 419 MPa, tensile strength is 573 MPa and the elongation is 18.3%. The results showed that the FeS2 is the main corrosion product on the inner and outer surfaces of the pipe based on the composition of the corrosion products. The hydrogen blistering and hydrogen induced cracking were also observed on the corrosion surface, which could be caused corrosion damage to the pipeline. These research results could provide theoretical basis and technical guidance for the corrosion protection and the hydrogen embrittlement prevention of 20# seamless steel in the high-sulfur gas well of the fifth gas production plant.