【作者】 罗玉梅；

【导师】 丁辉； 宁爱林；

【作者基本信息】 武汉大学 ， 机械工程， 2004， 硕士

【摘要】 B系列泵是我国引进技术生产的一种柱塞泵，其中关键零件缸体在国产化过程中不耐磨。生产厂家经过多年努力，寻找到了缸体较理想的代用材料是QT600-3球墨铁，而工件在常规淬火工艺中变形很大。激光淬火以加热冷却速度极快、工艺固定期短优势，能很好地使工件表面强化，增加耐磨性，而变形量又很少。激光淬火能解决B系列泵中缸体不耐磨和变形的问题。 本文从我国高功率CO₂激光工业应用发展水平出发，对激光淬火技术中涉及的工艺参数优化进行了系统的实验研究，简述了激光表面强化技术的研究及最新进展，介绍了QT600-3材料和QT600-3缸体激光淬火强化机理、设备装置，设计了实验方案和具体实验方法。 分析了QT600-3材料的激光淬火中矩形光束对表面硬度分布及淬硬层深度硬度分布的影响，实验过程中保持光斑大小不变，调整激光功率和扫描速度，得到了最佳的激光功率和扫描速度的范围，光斑大小为5mm×4mm时，QT600-3最佳的激光功率密度范围为W=4.5-5kw／cm²，扫描速度为v=4-5mm／s，淬硬层的宽度为4.5mm左右，淬硬层的平均硬度值达920HV，达到基体硬度的2.3倍左右，深度达0.55mm左右，激光淬硬层为均匀相变区和过渡区二个区域。激光淬火后材料比常规淬火的材料明显耐磨。 以QT600-3材料激光淬火优化工艺参数为基础，对QT600-3缸体工件进行宽带激光淬火研究。研究结果表明：QT600-3材料缸体采用的热处理工艺为：激光淬火，CO₂激光器宽带扫描，工艺参数取值范围为：W=4.5-5kw／cm²，v=4-5mm／s，就能实现缸体耐磨，变形少，彻底解决B系列泵国产化的关键技问题。更多还原

【Abstract】 The pump of B array is a filled pillar pump produced by our country with introductive technology, its key part cylinder block doesn’t wear resistant in national.QT600-3 Nodular iron, a more ideal substitution of cylinder block, is founded by years’ effort, but it deforms greatly in the normal quenching. Laser quenching takes the advantage of having a fast cool speed and a short fix time which can solve the wear resistant less and deformation problems.With the development of high power laser, much progress has been made in laser quenching processing and parameters optimization included which introduces the QT600-3 material and strengthen principles, facilities as well as the specific steps of experimentThe surface-quenching of QT600-3 material was carried out with a laser rectangle beam. The surface-hardness distribution and hardened depth with the hardened layer were studied. When he light spot is 5mm X 4mm, with the best laser power between 4 and 5.5 kw/cm2,the scanning speed at 4-5.5mm/s,the hardened with 4mm,the average misro-hardeness of Qt600-3 can reach 950Hv, Which is about 2.3 times as high as that of normal hardness, also the depth of 0.55mm is obtained. The hardened layer consists of two sub-layers, uniform phasetransfomation laser and transition layers. The material after laser quenched is obvious much more wear resistant than normal one.The study of QT600-3 cylinder block with wide-hand laser quenching which bused on the laser quenching optimal parameters of QT600-3 indicates that the hot process used by the QT600-3 cylinder block are: laser quenching wide-band CO2 laser scanning with the processing parameters are 4-5kw/cm2 of power and 4-5.5mm/s at speed. Then the wear resistance and little deformation of cylinder block can realize, so the key technique of B array pump can be solved completely.更多还原