【作者】 彭行金；

【导师】 邓琦林；

【作者基本信息】 上海交通大学 ， 机械制造及其自动化， 2007， 硕士

【摘要】 本文通过限元分析技术和实验研究进行了万向接轴叉头的动力学分析,得出了其运动理论工况;然后根据理论分析选择了几种工艺进行叉头虎口堆焊。焊后对式样进行了各种性能测试,根据这些测试结果比较,选择了一种最佳堆焊方式。通过有限元分析,叉头虎口的受力是正弦分布的,这是循环特性r下的变应力。根据图解法,算出叉头在理论情况下有较长的寿命。在一旦出现裂纹源的情况下,根据断裂力学理论,裂纹将慢慢扩大,最终导致工件断裂。本文根据Paris理论,得出叉头虎口一旦出现裂纹源,叉头虎口将在几天后失效。所以堆焊中控制裂纹是至关重要的,必须保证没有裂纹出现。采用激光和等离子两种方法堆焊修复虎口表面。其中激光采用同一种堆焊粉末,一种进行热处理,另一种不采用热处理;等离子堆焊采用两种不同的堆焊粉末,分别为Ni基和Fe基,都进行热后热处理。堆焊之后分别对式样进行拉伸、硬度测试、冲击、金相和成分分析。综合对比等离子和激光堆焊两种工艺,激光堆焊得到的组织比较细,激光堆焊经过热处理的2#工艺堆焊的硬度变化最平稳,并且有最大的硬度值;等离子堆焊的抗冲击性能比激光堆焊要好,但是激光堆焊的抗冲击性能比较平稳;激光堆焊堆焊层的最大拉伸强度可达1050Mpa左右,比起等离子堆焊的800Mpa左右,占非常明显的优势。不仅最大拉伸强度大,激光堆焊的堆焊层的各层拉伸率也比较平稳,没有大的波动。综合比较的可得出激光堆焊2#工艺具有最好的性能,所以万向接轴叉头虎口应该采用激光堆焊2#工艺进行修复。更多还原

【Abstract】 In this paper,by limit element analysis and experimental study of the universal joint s fork. Give the theory of the status of their movement and then According to the theoretical analysis choise several options process to cladding the fork Mouth. After welding several performance tests were done, based on these test results, select a best way .By finite element analysis, the Tiger’s Mouth fork is the sine distribution force, which is under the rcycle of stress. According graphic method, fork in the theoretical calculated under a longer life. In the event of a source of the cracks, in accordance with the theory of fracture mechanics, cracks will slowly expand, which eventually led to the workpiece fracture. Based on the Paris theory that the first event of a fork crack source fork in the Tiger’s Mouth will lapse after a few days. Therefore, welding cracks in the control is crucial, we must ensure that no cracks.Laser and plasma welding repair two methods Johannesburg surface. Which use laser welding with a powder, a kind of heat treatment, and do not use another kind of heat treatment; plasma surfacing using two different surfacing powder, respectively, and Ni-Fe-based, heat after heat treatment. Surfacing on the pattern followed by a stretch, hardness testing, impact, composition and microstructure analysis.Comparison of plasma and laser welding,laser welding have relatively small organization, laser welding, heat-treated # 2 surfacing of the most stable and changes in hardness, and the maximum hardness value; plasma surfacing Impact Performance is better than laser welding, laser welding of impact resistance is relatively stable, laser welding surfacing layer up to the maximum tensile strength of about 1050 Mpa, compared to the plasma surfacing about 800 Mpa, for very obvious advantages. Not only the greatest tensile strength, laser welding of weld overlay layers tensile rate is relatively stable, there are no major fluctuations.Comprehensive comparison can be drawn that #2 laser welding process is the best performance, so Universal joint fork should us`e the 2# laser welding process to repair .更多还原