STUDY ON A ROLLING PROCESS FOR （研究轧制过程）.pdfVIP

Rev. Adv. Mater. Sci. 33 (2013) 348-353 348 X. Xu, J. Kong, J. Lin and R. Zheng STUDY ON A ROLLING PROCESS FOR OBTAINING FERRITE-MARTENSITIC (DP) MICROSTRUCTURES IN ER70S-6 STEEL 1,2,3 1 2 1 Xiangjun Xu , Junqi Kong , Junpin Lin and Rongri Zheng 1School of Materials and Chemistry, Zhongyuan University of Technology, Zhengzhou 450007, P. R. China 2State Key Laboratory for Advanced Metals and Materials, University of Science and Technology Beijing, Beijing 100083, P. R. China 3Xingtai Iron and Steel Corporation Limited, Xingtai 054027, P. R. China Received: October 17, 2011 Abstract. The rolling process parameters of ER70S-6 steel for obtaining a ferrite plus martensite dual phase (DP) microstructure for high strength fasteners graded 8.8 were investigated. Thermal simulating experiments were carried out using Gleeble3500 simulator. Referring to the simulating results, the productive experiment was conducted in a continuous no-twist mill, and the mechanical properties of the as-rolled materials were tested. The results showed that deformed at 845 eC, followed by cooling to 780 eC at 5 eC /s and holding for 30 s, then quenching in water led to DP microstructure consisting of fine grained ferrite matrix plus about 20% martensite particles(in volume fraction). The wire rod rolled in this process route had a heterogeneous DP microstructure. Tensile strengths of the hot rolled DP wire rod and the drawn wire rod with a 19% reduction in area were 675-720 MPa and 915-970 MPa, respectively. ER70S-6 steel with DP mi