摘要：Grade 91 steel pipe was replaced after about 30 months of service. In this paper, the tensile properties, microhardness and chemical composition of the pipeline steel are systematically tested and analyzed. The results show that the properties of the steel still meet the requirements of relevant standards.
其他摘要：Grade 91 steel pipe was replaced after about 30 months of service. In this paper, the tensile properties, microhardness and chemical composition of the pipeline steel are systematically tested and analyzed. The results show that the properties of the steel still meet the requirements of relevant standards.
