南阳汽车发动机厂生产的6120柴油机曲轴,材质为铜钼球铁,牌号QT90-2,铸件重139公斤。采用横浇竖冷,原来的冒口形式见图1。规定不许用氧气切割冒口,只好在锯床下锯掉;冒口回炉时也要氧割成两段,增大了成本。随着生产的发展,在保证补缩的前提下,易割冒口成为急待解决的问题。易割冒口能够保证补缩的原理是:在浇注时易割隔片长时间被金属液加热,当 6120 diesel engine crankshaft produced by Nanyang Automobile Engine Factory is made of copper-molybdenum ductile iron with grade QT90-2 and 139 kilograms of casting weight. Vertical pouring cold, the original form of riser shown in Figure 1. Provisions are not allowed to cut riser with oxygen, had to saw it under the sawing saw; riser when the furnace should be cut into two oxygen, increasing the cost. With the development of production, under the precondition of guaranteeing re-tapping, easy-to-cut risers become an urgent problem to be solved. Easy cut riser to ensure that the principle of feeding is: easy to cut when casting tablets for a long time was heated liquid metal, when