重卡制动鼓铸件结疤缺陷的工艺对策

Process Countermeasures on the Scab Defects of Heavy Truck Brake Drum Castings

重卡制动鼓铸件具有外廓尺寸较大、轴向较高、壁厚较大等特点。生产过程中制动鼓法兰内圆角处易出现结疤缺陷,严重时导致铸件报废,造成生产成本的增加。通过生产全工序跟踪、纵向和横向综合分析,推测出采用湿型粘土砂机器造型生产制动鼓时法上述缺陷产生的机理,并结合实际生产提出了控制型砂质量、合理调整型砂参数指标、缩短浇注时间以及增大排气量等工艺措施。经过一系列的生产测试和验证,成功地消除了制动鼓法兰内圆角处结疤缺陷。

The heavy truck brake drum castings have the characteristics of larger outline sizes,higher axial height,larger thickness,and so on.During production process,the scab defects were prone to appear on the brake drum flange inner filleted corner positions,leading to casting scrapped when serious,and resulting in an increase in production costs.Through tracking of whole production process and comprehensive analysis of longitudinal and horizontal,the generation mechanisms of the defects mentioned above were speculated when the brake drums were manufactured by using of wet clay sand machine molding,and the process measures,such as controlling the quality of molding sand,adjusting the parameters of molding sand reasonably,shortening the pouring time,increasing the exhaust volume and so on,were put forward combining with the actual production.After a series of production tests and verification,the scab defects on the brake drum flange inner filleted corner positions were eliminated successfully.