Aihua WANG
,
Changsheng XIE
,
Kaijin HUANG
,
Beidi ZHU and Zengvi TAO (Dept. of Materials Science & Engineering
,
Huazhong University of Science & Technology
,
Wuhan
,
430074
,
China)
材料科学技术（英）
Laser cladding technique has been applied to renovate some partially-damaged (or worn) components with Fe, Ni, Co-base alloys, hence to improve their hardness values and wear resistance successfully in previous reports. But for some punching or shearing cast iron dies damaged or worn in automobile manufacture, the renovated surfaces also bear some impact loading. Therefore, a small-energy and multi-impact (SEMI) test was designed to investigate the fracture behaviour of renovated cast iron dies achieved by laser cladding of Fe and Ni-base alloys under SEMI loading to meet above requirement. observations show that the fracture took place in the substrate near to the substrate/coating interface rather than at the interface. The tempering temperature has a great influence on the cycles to fracture of laser-clad samples under SEMl loading, i.e. the low tempering temperature of 300℃ gives a maximum cycle to fracture, while a higher tempering temperature of 400℃ has a minimum. Furthermore, the fracture mechanism has also been discussed in present study
关键词:
Kaijin HUANG
,
Dawen ZENG
,
Changsheng XIE
,
Desheng XU
材料科学技术（英）
A 3D unsteady state numerical model of heat transfer in the circumferential laser oxygen cutting of pipes was developed. In order to minimize the computing time required for solving the finite difference equations as much as possible, the alternating direction implicit (ADI) method was adopted. Based on the characteristics of the pipe cutting process, the periodic boundary condition was applied to calculate the temperature distribution in the θ direction and the self-adaptive grid technology was also used. The mathematical model takes account of the temperature-dependent thermal properties of the pipe. The calculated kerfs width and the heat-affected zone (HAZ) were compared with the experimental results.
关键词:
Laser cutting
,
null
,
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