钢塑转换连接结构的研究

对不同结构形式的钢塑转换管件进行了拉伸荷载后密封测试试验。结果表明，钢塑结合处高密度聚乙烯（PE?HD）塑端的厚度对拉伸荷载后密封性能有影响，当结合处PE?HD塑端壁厚减薄越大时，拉伸测试时，越容易在该处发生屈服、拔脱或断裂泄漏；同时钢管端低高度齿形的过盈结构，对于较大口径管件更容易发生拔脱泄漏；采用注塑PE-HD塑端或提高一等级SDR值的加厚PE?HD管材塑端制成的钢塑转换管件优于普通PE-HD管材塑端制成的钢塑转换，前二者的安全裕度更高，此类管件在低温、PE?HD发生蠕变等极限条件下稳定性相对更好。

Research on Structure of PE to Steel Transition

A leak tightness experiment was performed for the steel-plastic-transition joint parts with different structures after tensile tests. The results indicated that that wall thickness of the joint parts had an influence on the leak tightness between the steel and high-density polyethylene （PE-HD） after tensile loading. When the wall thickness in the PE-HD part became smaller， the joint was more easily subject to yielding， pulling-out， rupture， or leakage. Meanwhile， the low?height anti-pulling-out gear structure of the steel part was more easily subject to pulling-out and leakage on the transitions with larger sizes. The transitions made from injection?molded PE-HD parts or PE?HD pipe segments with higher standard dimension ratios were found to exhibit better performance than those made from common PE?HD pipe segments. The first two types had higher safety margins and better stability at a low temperature and under the creeping process of PE?HD with extreme circumstances.