KOU Shu-qing, WANG Jin-wei, ZHENG Qi-feng, YANG Shen-hua. Organization and expansion breaking performance of fracture notch of crankshaft bearing and connecting rod by laser processing[J]. Editorial Office of Optics and Precision Engineering, 2011,19(4): 768-774
KOU Shu-qing, WANG Jin-wei, ZHENG Qi-feng, YANG Shen-hua. Organization and expansion breaking performance of fracture notch of crankshaft bearing and connecting rod by laser processing[J]. Editorial Office of Optics and Precision Engineering, 2011,19(4): 768-774 DOI: 10.3788/OPE.20111904.0768.
Organization and expansion breaking performance of fracture notch of crankshaft bearing and connecting rod by laser processing
Fracture splitting notches from C70S6 steel used in a connecting rod and from gray cast iron used in an engine crankcase main bearing bracket were processed by a YAG pulse laser
and the fracture splitting experiment was conducted in the fracture splitting device. The geometry appearances
microstructures
micro-hardness change as well as the fracture surface of fracture splitting notches were studied by a tool microscope
a scanning electronic microscope and a micro-hardness tester. Characteristics of fracture splitting notches processed by the pulse laser were discussed
and the influence of pulse laser processing fracture splitting notches from ductile/brittle materials on the expansion and breaking performance of the notchs was revealed. The results indicate that the geometry appearances and notch effects of the fracture splitting notches from ductile/brittle materials processed by the pulse laser are obviously superior to those of the broaching and linear cutting processing
and the gap sensitivity of gray cast iron has been strengthened greatly. The brittle martensite has been produced nearby the fracture splitting notches from ductile/brittle materials
and micro crack appears in the root of notch. The organization is obviously refined. The micro-hardnesses of melting zone and the solid phase transition zone of ductile/brittle materials approximately are 820/850 HV and 860/550 HV
respectively
which are higher than that of the substrate
and show a remarkable hardening effect. The ductile tearing phenomenon can not be seen in the C70S6 steel notch root zone. The ductile/brittle material fracture shows the brittle fracture characteristic
which satisfies the fracture splitting technological requirement.
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references
REPGEN B. Optimized connecting rods to enable higher engine performance and cost reduction . SAE TECHNICAL paper series 9800882 International Congress and Exposition Detroit, 1998:1-5.[2] 王国凡, 汤爱君,景财年,等. HT250 灰口铸铁的退火工艺和性能试验[J]. 金属热处理,2004,29(9):44-45. WANG G F, TANG A J, JING C N, et al.. Annealing process and property test of HT250 gray cast iron[J]. Heat Treatment of Metals, 2004, 29(9)44-45. (in Chinese)[3] 龚俊,芮执元,郎福元,等. 激光催裂的初步研究[J]. 甘肃工业大学学报,1994,20(4):4448. GONG J, RUI ZH Y, LANG F Y, et al.. The prelimi-nary study of laser-catalyzed cracking[J]. Journal of Gansu University of Technology, 1994,20(4):44-48. (in Chinese)[4] YILBAS B S. Laser cutting quality assessment and thermal efficiency analysis[J]. Journal of Materials Processing Technology, 2004,155-156:2106-2115.[5] LOISOS G,MOSES A J. Effect of mechanical and Nd∶YAG laser cutting on magnetic flux distribution near the cut edge of non-oriented steels[J]. Journal of Materials Processing Technology, 2005,161:151-155. [6] USOV S V,MINAEV I V. High-power impulse YAG laser system for cutting, welding and perforating of super hard materials[J]. Journal of Materials Processing Technology, 2004,149:541-545.[7] ABDEL G K,MEWISHY M. Cutting of 1.2 mm thick austenitic stainless steel sheet using pulsed and CW Nd∶YAG laser[J]. Journal of Materials Processing Technology, 2005,168:438-447.[8] 寇淑清, 杨慎华, 赵勇,等. 连杆断裂剖分前预置裂解槽激光加工方法及设备:中国,200410010722.1 .2005-01-05. KOU SH Q, YANG S H, ZHAO Y, et al.. Methods and Device of Prefabricating Fracture Splitting Notch Processed by Laser before Fracture Splitting Connecting Rod:Chinese,200410010722.1 .2005-01-05. (in Chinese)[9] 曹睿, 任学冲, 陈剑虹,等. 铸铁断裂机理原位拉伸研究[J]. 甘肃工业大学学报,2003 ,29(2):8-13. CAO R, REN X C, CHEN J H, et al.. In-situ stretching investigation on cast iron fracture mechanism[J]. Journal of Gansu University of Technology,2003,29(2):8-13. (in Chinese)[10] ZHANG D,HARRIS S J,MCCARTNEY D G, et al.. The effect of laser transformation notching on the controlled fracture of a high carbon (C70S6) steel[J]. Materials Science and Engineering,2008,489:273-284.[11] 徐祖耀. 马氏体相变与马氏体[M]. 北京:科学出版社,1980. XU ZH Y. Martensitic Transformation and Martensite[M]. Beijing: Science Press,1980. (in Chinese)