PRECIPITATION AND DISLOCATION STRENGTHENING BEHAVIOUR OF GRADE X80 STEEL FOR PIPELINE WITH STRAIN BASED DESIGN
This paper analyzes precipitation and dislocation strengthening behaviors of a 27mm thick Niobium-bearing Grade X80 steel plate for strain based design line pipe manufacture.The steel is produced by thermal-mechanical processing(TMCP)and is characterized with granular bainite and polygonal ferrite microstructure.Mechanical properties of both the steel and the UOE pipe are briefly introduced.Transmission electron microscope(TEM)is used to investigate the fine grain structure,distribution of the precipitates and dislocations in the steel.Precipitate morphologies,volume fractions of M(C,N),M3C,CaS,AlN and Cu are extensively studied respectively by Electrolytic Chemical Phase Analysis(ECPA)and X-ray Small Angle Diffraction(X-ray SAD).Dislocations in the steel are characterized with Positron Annihilation analysis.The results prove that precipitation hardening reveal a 58.1MPa strengthening contribution by the precipitates less than 20nm in size.Dislocation hardening is approximately 176MPa to the present studied steel and 198MPa to the pipe.
Line pipe steel Strain based design Precipitation Dislocations Nb-bearing steel
Weihua SUN Shu-e HU Guobao LI Hao YU
Shandong Iron and Steel Co.,LtdNo. 4 Building,2000 Shunhua Road,Jinan 250101 P. R.China University of Science & Technology Beijing30 Xueyuan Road,Haidian District,Beijing 100083 P. R.China
国内会议
杭州
英文
733-741
2015-11-11（万方平台首次上网日期，不代表论文的发表时间）