文档介绍：上海海事大学硕士学位论文姓名:鲍志军申请学位级别:硕士专业:机械设计及理论指导教师:宋光明 20070701 上海海事大学硕士学位论文:小模数齿轮激光熔覆修复工艺试验研究摘要本文研究了激光熔覆技术在小模数斜齿轮修复中的应用。小模数齿轮激光熔覆易产生齿面干涉、齿面裂纹、齿项塌陷等现象。试验结果表明, 合理选择光斑尺寸、扫描位置、扫描方法、工艺参数和熔覆顺序有助于获得平整光滑、齿面无裂纹、齿槽无凹陷、齿顶无塌陷的熔覆层。针对齿面熔覆时易出现裂纹的问题,设计了几种不同的熔覆方案,进行了几种不同方案的熔覆试验,最后确定了齿面熔覆的合理的工艺方法和工艺参数。齿面熔覆时对激光束与齿面的相对位置要求较高,否则易造成干涉,试验中通过合理的位置设计及选择适当的光斑大小解决了此问题。针对齿顶熔覆时易发生塌陷的问题,试验了多种不同的方案。提出了采用激光预置粉末的方法,即通过使用较低的激光能量密度预先扫描,使小部分粉末能熔化或呈微熔状态,依靠这部分粉末使大量的粉末粘结成团附着在齿顶表面,然后进行正式的激光熔覆,试验发现此工艺能解决齿顶塌陷问题。在进行整个轮齿及完整齿轮的熔覆中,面临的主要问题是热量的积累及热量的分布不均匀。在连续扫描过程中,热量的积累会造成后续熔覆时熔池保存时间长,从而造成熔体的流动,即材料的转移;热量分布的不均匀,会造成整个齿轮发生不均匀的变形。通过采用合理的扫描顺序及分齿方法等解决了遇到的热量积累及热量分布问题。关键词:小模数斜齿轮,激光熔覆,齿面熔覆,齿顶熔覆,齿顶塌陷,扫描方法,分齿方法上海海事大学硕士学位论文:小模数齿轮激光熔覆修复工艺试验研究 ABSTRACT Ithas been researched that laser cladding isappied tothe repairing of a close-toothed helical gear inthis cladding for a gear often meets such problems as the interference between the Iaser beam and the adjacent tooth flank,the crackings produced on the tooth flank coating。the caved tooth slot and the collapsed tooth experimental。study shows that the smooth, non·cracking。non-caving,non-collapsing coating on the gear tooth can be obtained by the intelligent selection ofthe beam size。the beam positioning,the scanning technique,the technological parameters and the cladding procedure. For the cracking problem on the tooth flank coating,various coating methods are designed and reseanable process method and parameter are cladding thetooth relative position between the laser spot and tooth flank iSdemanded severely。otherwise itis easy that the interference OCCURS,in the experiment the problem above isresolved through designing the rational relative position and selecting the appropriate spot size. For collapsing problem on the tooth tipcoating,various experiment methods have been carried method ofdepositing the powder in advance through the laser isproposed,that is,scanning inadvance through the lower energy