Abstract：The microstructure and mechanical properties of the 340 MPa-grade cold-rolled high strength low alloy (HSLA) steels with and without orange peel defects were analyzed. The results show that the yield point elongation of the stress-strain curve of the defective steel plate reaches 3.73%. The yield extension is too large, which leads to the orange peel defect on the surface of the stamped front windshield beam connecting plate. In the laboratory, the technique of the pre-stretching of the steel sheets is used to simulate the skin pass and stretching straight process for the industrial production of the steel sheets. With the increasing the pre-deformation amount, the length of the yield platform of the sample decreases, and when the pre-tension amount exceeds 1.8%, the yielding platform of the sample disappears. Further analysis of the microstructure reveals that the high annealing temperature leads to the coarse grain size and the abnormal grain orientation, which is the root cause of the "orange peel" defect of the stamped steel plate. In the annealing process, the reasonable control of leveling and tension straightening can eliminate or shorten the length of the yield platform of the test steel and avoid the occurrence of orange peel defects on the stamping parts.
王立辉, 李建新, 孙力, 安会龙, 马成, 董伊康. HC340LA钢冲压“桔皮”缺陷成因及措施[J]. 中国冶金, 2020, 30(3): 64-68.
WANG Li-hui, LI Jian-xin, SUN Li, AN Hui-long, MA Cheng, DONG Yi-kang. Causes and improvement measures of stamping orange peel defects of HC340LA steels[J]. China Metallurgy, 2020, 30(3): 64-68.
CAO S Q,ZHANG J X,WU J S,et al. Analysis of orange peel defect in St14 steel sheet by electron backscattered diffraction(EBSD) [J]. Journal of Materials Science and Technology, 2005, 21(1): 17.
Lüders W. Über Die äusserung der Elasticität an Stahlartigen Eisenstaben und Stahlstäben, und über Eine Beim Biegen Solcher Stäbe Beobachtete Molecular Bewegung[J]. Dinglers Polytechnische Journal,1860(155):8.
Charit I, Seok C S, Murty K L. Synergistic effects of interstitial impurities and radiation defects on mechanical characteristics of ferritic steels[J].Journal of Nuclear Materials,2007,361(2):262.
[12]
Hall E O. The deformation of low-carbon steel in the blue-brittle range[J].Journal of the Iron and Steel Institute,1952(170):331.
[13]
田中青. 冷轧析出强化钢拉伸应变痕产生机理及影响因素[J]. 南方金属,2015(4):47.
[14]
Riccardo R,Carlo M,Roberto V. Effect of coiling temperature on formability and mechanical properties of mild low carbon and HSLA steels processed by thin slab casting and direct rolling[J].ISIJ International, 2007,47(8):1204.
2020, Vol. 30 
