填充四氟作为一种自润滑材料使用日益广泛,尤以制作活塞环,密封环为多。活塞环和密封环的工作性能与开口尺寸、侧隙和与缸壁的贴合状况有很大关系。纯聚四氟乙烯线胀系数在8～25×10~(-5)/℃内变化。填充四氟经过填充剂的改性其线胀系数常在0.8～1.9×10~(-4)/℃范围变化,这与填充材料的成份、配比以及成型工艺有关。由于它的线胀系数比铸铁大得多(铸铁为1×10~(-5)/℃),因此,活塞环的加工尺寸不能按铸铁活 Filled with PTFE as a self-lubricating materials increasingly widespread, especially in the production of piston rings, seal ring and more. Piston rings and seal ring work performance and the opening size, backlash and the cylinder wall with a great relationship between the status. Linear expansion coefficient of pure PTFE in 8 ~ 25 × 10 ~ (-5) / ℃ within the change. The linear expansion coefficient of PTFE filled with filler is often varied in the range of 0.8-1.9 × 10 -4 / ℃, which is related to the composition of filling material, formulation and molding process. Because of its linear expansion coefficient is much larger than cast iron (cast iron is 1 × 10 -5 / ℃), therefore, the processing size of the piston ring can not be cast iron live