The material of this kind of pistons is HNBR supplied by American DuPont company and Japanese Zeon company which apply to high-temperature, high pressure, high-corrosion working environment. The maximum working pressure is 75MPa. The working temperature is up to 150 a??.HNBR is one new material with superior comprehensive properties and is widely used for aviation industry.It has been also used for the oil industry in recent years, HNBR has excellent performance for wear resistance, chemical resistance and oil resistance.It also has good resistant properties for amine and steam.Especially in high-temperature, high-pressure working environment, the-ordinary rubber is easily damaged for the role of hydrogen sulfide, carbon dioxide, methane, steam and acid environment, but HNBR has shown a good comprehensive performance.