球阀阀座用聚三氟氯乙烯密封环工艺与性能

Performances and Processes of Poly-trifluorochloroethylene Seat Sealing Ring for Ball Valve

选用两种不同降温方式探究压制成型工艺对球阀阀座用聚三氟氯乙烯(PCTFE)密封环密封性能的影响。低温试验结果表明,自然降温工艺成型的制品外表面在常温-低温循环工况下出现裂纹,而保压降温得到的制品则不出现上述问题。性能测试与表征分析结果表明,自然降温工艺成型的密封环PCTFE其内部会出现微裂纹等缺陷,导致其在低温测试后出现亚表面裂纹,造成密封失效。降温阶段保压操作可抑制材料成型阶段微裂纹缺陷的产生,避免材料在室温-低温循环工况下因内应力而产生裂纹缺陷。

Two molding press processes with different cooling methods were adopted to manufacture polytrifluorochloroethylene(PCTFE)seat sealing ring for ball valve.The results of cryogenic experiments show that internal micro-cracks would occur in the PCTFE product prepared by press process with natural cooling,while the one prepared by press process with pressurized cooling will not generate intrinsic micro-cracks.The results of characterizations and performance tests indicate that molding press process with natural cooling leads to occurrence of micro-cracks in the product,resulting in the subsurface defects during the cryogenic experiments and seal failure.Pressurizing the product during cooling will inhibit the occurrence of micro-cracks,avoiding the appearance of aggravated cracks due to the internal stress generated by the room-low temperature cycle condition.