从应用角度考虑塑料压力管的力学破坏问题

Consideration of mechanical fracture for plastics pressure pipe as viewed from application

建立和完善快速裂纹增长危险和长期寿命—长期强度性能的质量监控体系对塑料压力管持续发展至关重要。聚氯乙烯管材的抗冲击性能、Ｃ 环法断裂韧性、聚乙烯管的断裂伸长率数据在应用中都有明确的针对性。拉伸屈服强度、打压爆破压力、Ｉｚｏｄ 或Ｃｈａｒｐｙ 抗冲击强度、Ｂｅｌｌ 法耐环境应力开裂性数据等与塑料压力管实际应用关系不大。塑料管的耐老化性能及焊接质量与力学破坏有关，是需要重视的问题。塑料压力管在其适用范围内，有足够的承压能力和刚性，满足实际使用的需要。

It is of utmost importance for continuous development of plastics pressure pipe to set up and perfect the quality assurance system against the risk of rapid crack propagation and for the necessary long service life ____long term strength. The impact-resistant property, C loop method breakage tough for PVC pipe and breakage stretch rate for polyethlene pipe have clarified requirements in application. The weathering quality of plastics pipe is a valued question, which is relative with welding quality and mechanical fracture. The plastics pressure pipe has enough pressure bearing capacity and rigidity to meet the actual use requirement within its proper range.