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对活塞顶部挤压折叠缺陷产生的原因进行了分析,发现折叠缺陷是由于余料太薄引起的缩尾性折叠;分别对增厚坯料法、方形坯料法和两步挤压法进行了分析比较,结果表明采用增加坯料厚度的方法来防止折叠不仅增加了材料的浪费,也会增大后续的机加工量,是不经济的;方形坯料虽说可以有效的避免活塞顶部金属对流情况,但是会在活塞环岸内侧产生折叠;而两步挤压法有效的防止了活塞销顶部金属对流的情况,有效的避免了活塞顶表面折叠的产生。
The reasons for the collapse and collapse of the top of the piston were analyzed and it was found that the folding defect was due to the shrinkage fold caused by excessively thin material. The thickening, square billets and two-step extrusion were analyzed and compared The results show that it is uneconomical to increase the thickness of the blank to prevent the folding not only increasing the material waste but also increasing the subsequent machining volume. Although the square blank can effectively avoid the metal convection at the top of the piston, The inner side of the piston ring shore is folded, while the two-step extrusion method effectively prevents metal convection on the top of the piston pin and effectively avoids the folding of the piston top surface.