（1. Sheet Metal Research Institute， Technology Institute of Shougang Group Co.， Ltd.， Beijing 100043， China 2. Beijing Key Laboratory of Green Recyclable Process for Iron and Steel Production， Beijing 100043， China 3. Manufacturing Department， Qian’an Iron and Steel Company of Shougang Group Co.， Ltd.，Tangshan 064404， Hebei， China）
Abstract：In order to develop a new 440 MPa grade high strength bake hardening steel，the microstructure，properties，strengthening mechanism and bake hardening mechanism were investigated by utilizing optical microscope （OM） and transmission electron microscopy （TEM）. The results showed that the microstructure was composed of ferrite and a small amount of pearlite. With the increase of mass percent of N and the decrease of coiling temperature，the ferrite would be refined. The ferrite grain sizes of the low N steel were 8.34 and 7.89 μm when coiling at 630 and 600 ℃，respectively. The contribution of fine grain strengthening to yield strength was 190 and 196 MPa，respectively. The ferrite grain sizes of the high N steel were 6.93 and 6.71 μm when coiling at 630 and 600 ℃，respectively. The contribution of fine grain strengthening to yield strength was 209 and 212 MPa，respectively. Both the yield strength and tensile strength exhibited an ascending tendency after bake hardening treatment. The smaller of the grain size and the higher of the mass percent of N was，the larger value of the tensile strength was. The BHT values of the high mass percent of N steel at 10% prestrain were all above 70 MPa and the tensile strength reached over 500 MPa，which mainly because the dislocations introduced by prestrain become firm during the baking treatment and promote dislocation enlargement and reborn during plastic deformation.
收稿日期: 2018-03-09
出版日期: 2018-10-26
引用本文:
惠亚军，潘 辉，肖宝亮，吴科敏，李晓林，张大伟. 440 MPa级新型高强度烘烤硬化钢的组织与性能[J]. , 2018, 53(10): 79-84.
HUI Ya-jun，，PAN Hui，XIAO Bao-liang，WU Ke-min，LI Xiao-lin，ZHANG Da-wei. Microstructure and properties of a new 440 MPa grade high strength bake hardening steel. Iron and Steel, 2018, 53(10): 79-84.
2018, Vol. 53 
