Microstructures and Properties of 550 MPa Grade High Strength Thin-walled H-beam Steel  

作　　者：CHEN Jiping KANG Yonglin QIAN Jianqing LI Shengzhi QIAN Haifan 

机构地区：[1]School of Materials Science and Engineering,Key Lab of Metals and Processing of Anhui Province,Anhui University of Technology [2]School of Materials Science and Engineering,State Key Laboratory for Advanced Metals and Materials,University of Science and Technology Beijing [3]Ma'anshan Iron and Steel Co. Ltd

出　　处：《Journal of Wuhan University of Technology(Materials Science)》2013年第6期1217-1222,共6页武汉理工大学学报（材料科学英文版）

基　　金：Funded by the "11th Five" National Science and Technology Support Project(No.2006BAE03A13)

摘　　要：The microstructures and mechanical properties of 550 MPa grade lightweight high strength thin-walled H-beam steel were experimentally studied. The experimental results show that the microstructure of the air-cooled H-beam steel sample is consisted of ferrite, pearlite and a small amount of granular bainites as well as fine and dispersive V（C,N） precipitates. The microstructure of the water-cooled steel sample is consisted of ferrite and bainite as well as a small amount of fine pearlites. The microstructure of the water-cooled sample is finer than that of the air-cooled sample with the average intercept size of the surface grains reaching to 3.5 gna. The finish rolling temperature of the thin-walled high strength H-beam steel is in the range of 750 ~C-850 ~C. The lower the finish rolling temperature and the faster the cooling rate, the finer the ferrite grains, the volume fraction of bainite is increased through water cooling process. Grain refinement strengthening and precipitation strengthening are used as major strengthening means to develop 550 MPa grade lightweight high strength thin- walled H-beam steel. Vanadium partially soluted in the matrix and contributes to the solution strengthening. The 550 MPa grade high-strength thin-walled H-beam steel could be developed by direct air cooling after hot rolling to fully meet the requirements of the target properties.The microstructures and mechanical properties of 550 MPa grade lightweight high strength thin-walled H-beam steel were experimentally studied. The experimental results show that the microstructure of the air-cooled H-beam steel sample is consisted of ferrite, pearlite and a small amount of granular bainites as well as fine and dispersive V（C,N） precipitates. The microstructure of the water-cooled steel sample is consisted of ferrite and bainite as well as a small amount of fine pearlites. The microstructure of the water-cooled sample is finer than that of the air-cooled sample with the average intercept size of the surface grains reaching to 3.5 gna. The finish rolling temperature of the thin-walled high strength H-beam steel is in the range of 750 ~C-850 ~C. The lower the finish rolling temperature and the faster the cooling rate, the finer the ferrite grains, the volume fraction of bainite is increased through water cooling process. Grain refinement strengthening and precipitation strengthening are used as major strengthening means to develop 550 MPa grade lightweight high strength thin- walled H-beam steel. Vanadium partially soluted in the matrix and contributes to the solution strengthening. The 550 MPa grade high-strength thin-walled H-beam steel could be developed by direct air cooling after hot rolling to fully meet the requirements of the target properties.

关 键 词：H-beam steel high strength thin-walled vanadium-nitrogen microalloying microstructure and mechanical property strengthening mechanism 

分 类 号：TG335.4[金属学及工艺—金属压力加工]