Cast iron piston and machining method

The invention provides a cast iron piston which adopts an integrated structure, so that the performance of the piston is more stable, the influence of other impurities is avoided, and the product reliability is improved. The piston comprises a piston head part and a piston skirt part, the piston head part and the piston skirt part are of an integrally-formed structure, an annular cooling oil channel is formed in the piston head part, an oil inlet hole and an oil outlet hole are formed in one diagonal direction of the cooling oil channel, and auxiliary holes are formed in the other diagonal direction of the cooling oil channel. 本发明提供了一种铸铁活塞，其采用一体式结构，则活塞性能更加稳定，且无其他杂质的影响，提高了产品可靠性。其包括活塞头部和活塞裙部，所述活塞头部与所述活塞裙部为一体成型结构，所述活塞头部的内部设有环形的冷却油道，所述冷却油道的一个对角方向上分别设有进油孔、出油孔，所述冷却油道的另一个对角方向上分别设有工艺孔。