DISCUSSION ON FEASIBILITY OF TECHNIQUE OF TWO-COMPONENT EPOXY COATING USED ON WELD JOINT COATING OF 3PE PIPELINE
三层聚乙烯防腐管线双组分环氧涂层补口问题分析及其技术的可行性探讨

The authors analyzed the main causes related to the concern that a lot of epoxy coatings on PE chamfers cracked during the first trial construction of two-component epoxy coating used on the weld joint coating of 3PE pipeline,probed and discussed the feasibility of this new joint coating technique,the main conclusions are as follows:if the coating cracks during the curing course were caused by lower ambient temperature,the concern should be the negligence of quality control in relation with project management;it is possible that the frequency of temperature change,the amplitude of temperature difference and the convex ridge on chamfers or the brush trace in coatings are the comprehensive causes for the coating cracks;coatings did not crack after being cured,this kind of weld joint coating mode will have the function for restricting the deformation of PE layer;coatings crack only at the top ridge of chamfers and do not at the bottom edge after the coatings are cured,it do not have too serious effect on the function of pipeline anti-corrosion system;at the beginning period of generalization and application of this new weld joint coating technique,the chamfers should be covered by wrapping adhesive tapes or others around it at the same time that a certain distance of the epoxy primer layer protruding out of the PE layer is ensured;the mechanism of epoxy coating cracking at chamfer surface should be lucubrated further.