Research on Processing， Microstructure and Properties of X80 High-Deformability Pipeline Steel
ZHANG He-song， KANG Yong-lin， MENG De-liang， XIA Dian-xiu， AN Shou-yong
1. State Key Laboratory for Advanced Metals and Materials， School of Materials Science and Engineering， University of Science and Technology Beijing， Beijing 100083， China
2. Technology Center， Ji'nan Iron and Steel Co.， Ltd.， Ji'nan 250101， Shandong， China
The alloy composition of X80 high-deformability pipeline is designed in this research. The X80 high-deformability pipeline steel was processed by TMCP rolling and two-stage controlled cooling in laboratory and it is realized in industry trail. The effects of cooling conditions on the microstructure and mechanical properties of the steel were investigated by SEM, TEM, tensile test and Charpy impact test. Ferrite + Bainite dual phase microstructure can be obtained by using two stage controlled cooling process. When the accelerated cooling finishes at 450℃ and the cooling rate is 20℃/s, the volume fraction of Ferrite and Bainite will get the best ratio; the average grain size of M/A islands is approximately 1 μm. The uniform microstructure provides good combination of strength-ductility properties．
2012, Vol. 22 
