Pipeline installed and put into operation, the temperature inside the tube is often due to the medium and ambient temperature difference generated when installing retractable.In addition, since the level of the operating temperature of the pipeline itself, will cause the telescopic pipe. Experimental results show that the temperature changes caused by pipe length is proportional to the change. Piping temperature rises, due to the expansion, increasing the length; temperature drops, due to shrinkage, reduced length. A temperature coefficient of linear expansion is proportional to the length of the corresponding amount of change called pipe. Linear expansion coefficient of different materials are also different.

If the ends of the pipe is not fixed, allowing it to free expansion, the thermal expansion amount to no effect on the strength of the tube. If both ends of the pipe to be a restriction that prevents the tube stretching, then in the inner tube will generate a lot of heat stress. Heat stress generated by the heat pipe, and pipe only elastic modulus,linear expansion coefficient, the length of the pipe section when the pipe is heated and the temperature change range, but not to the diameter size and wall thickness.