Causes of thermal expansion of seamless steel pipes

Causes of thermal expansion of seamless steel pipes

When seamless pipes are installed and put into operation, they often expand and contract due to the difference between the temperature of the medium in the pipe and the ambient temperature during installation. In addition, due to the working temperature of the pipeline itself, it will also cause expansion and contraction of the pipeline. Experiments have shown that changes in temperature cause proportional changes in pipe length. When the temperature of the pipe increases, the length increases due to expansion; when the temperature decreases, the length decreases due to contraction. The proportional change in length corresponding to a temperature change of 1 degree is called the linear expansion coefficient of the pipe. The linear expansion coefficients of different materials are also different. The linear expansion coefficient of carbon steel seamless pipes is 12×10-6/℃, while the linear expansion coefficient of rigid polyoxyethylene pipes is 80X101-6/℃, which is about seven times that of carbon steel seamless pipes.

Seamless steel pipe thermal expansion calculation formula

Thermal expansion = Thermal expansion coefficient of steel pipe * Steel pipe length * (temperature during use - temperature during installation)

Effect of Thermal Expansion of Seamless Steel Pipes

Thermal expansion of seamless pipe form welding reduces the residual stress generated during pipe form welding, improves its distribution, and improves the comprehensive mechanical properties of the steel pipe. These changes should be fully taken into account when developing seamless steel pipes. The width, length and thickness of the tube plate should be considered, as well as the outer diameter of the steel pipe before expansion, so as to avoid the geometric dimensions of the steel pipe after expansion not meeting the final requirements. For different square moments, cold expansion also has the effect of improving the straightness of seamless steel pipes, especially the straightness effect of small-diameter seamless steel pipes is more obvious.

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