对於低压水管或火管锅炉,其锅筒、管板与管子的胀接是一种常用的联接方式。因为对这类锅炉来说承压低,对水质的要求也较低,因此在能确保管子与管孔具有良好的严密性的前提下,为了便於更换管束就往往采用胀接形式。另外,胀接管在运行中如果由於管理不当而造成超压或超温事故时,胀接联接处便会先行泄漏,相对焊接管来说,不易造成爆炸危险,这一点从安全角度考虑,也是很有价值的。胀管工艺的实质是采用胀管器使管子产生塑性变形,而管孔除孔边缘有少量塑性变形外,管孔周围金属主要产生弹性变形,这样当取出胀管器后,孔板产生的弹性变形力图恢复原始状态,而已产生塑性变形的管子管径已胀大而不能恢复原状,这样管孔壁弹性变形不能 For low pressure water pipe or fire tube boiler, the expansion of its drum, tube plate and pipe is a commonly used method of connection. Because these boilers have low pressure and low water quality requirements, they are often used to facilitate the replacement of tube bundles in order to ensure good tightness between the tubes and the tube holes. In addition, expansion joints in operation if due to improper management caused by over-pressure or over-temperature accident, the expansion joints will be the first joint leakage, relative to the welded pipe, not easy to cause an explosion hazard, which is from a security point of view, is also very valuable. Expansion of the essence of the tube expansion tube is used to produce plastic deformation of the pipe, and the hole in addition to a small hole on the edge of the plastic deformation, the hole around the metal tube mainly produces elastic deformation, so that when removing the expander, orifice elastic Deformation force map to restore the original state, and has produced plastic deformation of the tube diameter has swollen and can not be restored to its original shape, so that the elastic deformation of the tube wall can not