铸造锌铝合金蜗轮制件磨损失效分析及防止措施

Analysis on Wear Failure of Worm Gear of Zinc-aluminum Alloy and Countermeasures

针对铸造锌铝合金蜗轮制件表面磨损的形貌,借助扫描电镜、能谱分析等手段,综合分析了蜗轮制件表面磨损失效的机制。结果表明,蜗轮制件表面磨损失效的具体原因是:蜗轮铸件化学成分不均匀引起的力学性能大幅度降低;铸件热节处出现的缩孔、缩松、气孔和夹杂等缺陷,破坏了金属基体的连续性,夹杂物脱落作为磨粒加重摩擦副间的磨损;零件的加工精度、安装精度低,工作受力不均匀;减速箱工作中润滑不良等。提出了提高铸件质量,减小磨损,延长铸造锌铝合金蜗轮制件使用寿命的具体改进措施。

The wear morphology of worm gear of as-cast zinc-aluminum alloy was analyzed by means of SEM and EDS, and the failure mechanism of surface wear of worm gear was discussed. The failure reasons are that the non-uniform composition in worm gear casting causes the sharp decrease of mechanical properties; these defects existed in hot spots, such as shrinkage, porosity shrinkage, blowhole and inclusions, destroy the continuity of matrix, and the fall off of inclusion as grits can aggravate wear of the friction pair; and the low machining precision and installation accuracy, non- uniform working load and poor lubrication in gear box also affect the failure of worm gear. The countermeasures are proposed, which include improving the quality of casting, decreasing wear and prolong the service life of worm gear of as-cast zinc-aluminum alloy.