2024-04-30 08:58:08 评论： 点击：
Plastic coated steel pipes for gas pipelines must not only meet the strength requirements (mechanical properties) and weldability, but also take into account environmental temperature, pipe diameter, conveying pressure, and the corrosiveness of the conveying medium; Consider the impact toughness, ductile brittle transition temperature, and corrosion resistance of steel. The fracture requirements for coated steel pipes used in gas pipelines are very strict, and pipeline fracture can be divided into ductile fracture and brittle fracture.
燃气管线用涂塑钢管除必须满足强度要求(力学性能)和焊接性外，还需根据环境温度、管径大小、输送压力及输送介质的腐蚀性等条件；考虑钢材的冲击韧性、韧脆转变温度和耐腐蚀性能。
燃气管线用涂塑钢管对钢管的断裂要求非常严格，管线断裂可分为韧性断裂和脆性断裂。燃气管线用涂塑钢管韧性断裂是在过大拉应力和裂纹缺陷同时存在的条件下，由细小的裂纹逐渐扩展而最终造成的断裂。其断面呈暗灰色纤维状。
燃气管线用涂塑钢管脆性断裂，是由低温、应力和裂纹缺陷三种条件共同作用造成的，其断裂常在远低于钢材屈服应力条件下突然发生，断裂后的断裂面呈发亮的结晶状。对于高强度、厚壁、韧性低的管材在低温、高应力使用条件下容易发生断裂。为了防止燃气管线用涂塑钢管在工作条件下断裂，在制管和施工中应注意消除管线裂纹缺陷。并从选择管线用钢，提高钢材韧性来防止燃气管线用涂塑钢管裂断。
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