|
|
Cause analysis of surface crack defects of gear steel 20CrNiMo rolled product |
LIN Peng, ZHANG Hong-cai, LIU Ying, XU Zheng-zhou |
Huaigang Special Steel Co., Ltd., Jiangsu Shagang Group, Huai'an 223002, China |
|
|
Abstract For the gear steel 20CrNiMo rolled material with specification of more than[?80 mm,]it was found that the defect detection rate was low. Moreover, the problem of crack defects on the surface of rolled product was also observed. Based on the analysis of crack defects of the rolled products, the cracks were possibly caused by the crack defects in the billet. In order to verify this point of view and find out the exact reason so as to provide solutions, the shot blasting inspection of billet surface was firstly conducted, and no crack defect was observed. Secondly, the defects of the rolled product prepared from billet with cracks and the surface cracks of rolled product were compared and analyzed by metallographic microscope. It was found that the crack morphology and decarburization degree around were different, which indicated that the cracks on rolled product were not caused by the defects of the billet. Finally, the surface of cast billet was found to be seriously scratched and pitted by blasting the billet after slow cooling and be similar to that of the rolling cracks. The results showed that the cracks and warping defects were caused by scratches and pits in the process of casting but not caused by crack defects of the billet.
|
Received: 24 September 2019
|
|
|
|
[1] |
LI Lan-xin1,WANG Min1,JUAN Rong-fei1,BAO Yan-ping1,YANG Jin2. Distribution characteristics of oxides and sulfide inclusions in key areas of gear steel forgings[J]. JOURNAL OF IRON AND STEEL RESEARCH , 2020, 32(5): 370-376. |
[2] |
AI Ke-nan, ZHANG Pan-pan, ZHAO Meng-hao, LI Cheng-liang, ZHANG Zhi-ming, FU Jian-xun. Analysis of formation mechanism of surface crack of 1215 free-cutting steel during drawing[J]. Iron and Steel, 2020, 55(2): 88-94. |
[3] |
LIU Haining,WANG Ying,LI Renxing,TENG Lihong,HE Xi,ZHONG Honggang. Application of pulse magnetooscillation homogenization technique #br# on continuous casting of 20CrMnTi gear steel[J]. Iron and Steel, 2019, 54(6): 69-78. |
[4] |
SHEN Bin-bin. Discussion about the thermoplasticity of vanadium microalloyed steel[J]. PHYSICS EXAMINATION AND TESTING, 2019, 37(5): 9-11. |
[5] |
ZHANG Guo-qiang, HE Xiao-fei, YU Wen-chao, SHI Jie, WANG Mao-qiu. Grain coarsening behavior of high temperature carburizing gear steels[J]. Iron and Steel, 2019, 54(5): 68-72,77. |
[6] |
BAI Xu-xu, YANG Shu-feng, LIU Wei, LI Jing-she, LIANG Xue. Effect of tellurium treatment on modification of MnS inclusion in 20CrMnTi gear steel[J]. Iron and Steel, 2019, 54(12): 35-41. |
|
|
|
|