一、改革前我厂制造的6250型柴油机铝活塞根据设计要求顶部采用油腔冷却。顶部的油腔形状是用1毫米紫铜皮卷铸成,支管是用φ10、φ12紫铜管弯成,再经过焊接,组合成铜管泥芯。焊缝要修光,流道要畅通,然后液压试验不漏水(见图1)。铝活塞浇好后,浸到加热过的高浓度的硝酸中,经过三小时后方能将铸件内的铜管 First, before the reform, the 6250 diesel engine aluminum piston manufactured by our factory adopted the oil chamber cooling according to the design requirements. The shape of the top of the oil chamber is cast with a 1 mm purple copper coil, the branch is bent into φ10, φ12 purple copper tube, and then after welding, combined into copper pipe mud core. Welds to repair light, runner to flow, and then hydraulic test watertight (see Figure 1). After pouring aluminum piston, immersed in heated high concentration of nitric acid, after three hours before the casting can be brass