活塞涨圈是薄而窄的环形零件(厚度和宽度与直径比较相差很大),它在自由状态时具有一定的特殊形状,将其压缩到规定的切口间隙时即呈正圆形,在内应力的作用下能贴紧在气缸壁上。因此,涨圈要求有一定的弹力,并有正圆度和平面度的要求,此外尚要求热稳定性(工作温度为200℃)、耐磨、抗腐蚀及小的摩擦系数等。制造铸铁涨圈的方法有几种,它们的区别是使涨圈获得得弹性的方法以及采用的毛坯形状 Piston ring is thin and narrow ring parts (the thickness and width of the difference between the diameter and very large), it has a special shape in the free state, it will be compressed into the provisions of the gap when the gap was a positive circle, the internal stress Under the action can be closely attached to the cylinder wall. Therefore, up ring requires a certain degree of resilience, and roundness and flatness requirements, in addition to still require thermal stability (working temperature is 200 ℃), wear resistance, corrosion resistance and small friction coefficient. There are several ways to make cast iron rings, the difference between them is the way the ring is made flexible and the shape of the blank used