WANG Donglin, JIANG Hong, ZHANG Qi, et al. Physical & chemical properties and common problems analysis of X90 straight seam pipe[J]. 2021,51(11):40-43.
WANG Donglin, JIANG Hong, ZHANG Qi, et al. Physical & chemical properties and common problems analysis of X90 straight seam pipe[J]. 2021,51(11):40-43. DOI: 10.7512/j.issn.1001-2303.2021.11.07.
In order to strengthen the quality control of high performance steel pipe, the chemical composition, mechanical properties and metallographic microstructure of X90 straight seam pipe produced by 10 major domestic steel pipe plants are analyzed in detail. The performance control of X90 straight seam pipe is analyzed, and the control degrees of each element of chemical composition, tensile properties, impact properties and hardness are ranked. At the same time, the problems of X90 straight seam pipe are analyzed from two aspects of performance and welding embitterment, and the corresponding cause analysis and treatment direction are provided. The results show that the control of the chemical components of Nb+V+Ti, P, CEpcm and Mn should be strengthened. The control degree ranking of tensile property is elongation >tensile strength > yield strength, and special attention should be paid to the control of yield ratio. The control degree ranking of average impact energy is base metal transverse control > heat affected zone transverse control > weld transverse control. But the control degree ranking of standard deviation of impact energy is weld transverse control > base metal transverse control > heat affected zone transverse control. PF in the fusion zone of metallographic microstructure accounts for a large proportion, which is the main cause of softening and should be paid close attention to.