1. Reasons for thermal expansion of seamless steel pipes
When the seamless pipe is installed and put into operation, it often expands and contracts due to the difference between the temperature of the medium in the pipe and the ambient temperature during installation. In addition, due to the high and low working temperature of the pipeline itself, the expansion and contraction of the pipeline will also be caused.Experiments have shown that the change in temperature causes a proportional change in the length of the pipe. 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, and the linear expansion coefficient of different materials is also different. The linear expansion coefficient of carbon steel seamless pipe is 12×10-6/℃, while the linear expansion coefficient of rigid polyoxyethylene pipe is 80X101-6/℃, which is about seven times that of carbon steel seamless pipe.
2. Calculation formula for thermal expansion of seamless steel pipe
Thermal expansion = thermal expansion coefficient of steel pipe * length of steel pipe * (temperature during operation - temperature during installation)
3. Influence of thermal expansion of seamless steel pipe
The thermal expansion of the seamless tube forming welding reduces the residual stress generated by the forming and welding of the tube, improves its distribution, and improves the overall mechanical properties of the steel tube. These changes should be fully taken into account when developing seamless steel pipes. The width, length and thickness of the tube sheet should be considered, and the outer diameter of the steel tube before expansion should be considered, so that the geometric size of the steel tube after expansion cannot meet the final requirements. For different squares, the cold expansion path also has the effect of improving the straightness of the seamless steel pipe, especially the straightness effect of the small-diameter seamless steel pipe is more obvious.
When the seamless pipe is installed and put into operation, it often expands and contracts due to the difference between the temperature of the medium in the pipe and the ambient temperature during installation. In addition, due to the high and low working temperature of the pipeline itself, the expansion and contraction of the pipeline will also be caused.Experiments have shown that the change in temperature causes a proportional change in the length of the pipe. 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, and the linear expansion coefficient of different materials is also different. The linear expansion coefficient of carbon steel seamless pipe is 12×10-6/℃, while the linear expansion coefficient of rigid polyoxyethylene pipe is 80X101-6/℃, which is about seven times that of carbon steel seamless pipe.
2. Calculation formula for thermal expansion of seamless steel pipe
Thermal expansion = thermal expansion coefficient of steel pipe * length of steel pipe * (temperature during operation - temperature during installation)
3. Influence of thermal expansion of seamless steel pipe
The thermal expansion of the seamless tube forming welding reduces the residual stress generated by the forming and welding of the tube, improves its distribution, and improves the overall mechanical properties of the steel tube. These changes should be fully taken into account when developing seamless steel pipes. The width, length and thickness of the tube sheet should be considered, and the outer diameter of the steel tube before expansion should be considered, so that the geometric size of the steel tube after expansion cannot meet the final requirements. For different squares, the cold expansion path also has the effect of improving the straightness of the seamless steel pipe, especially the straightness effect of the small-diameter seamless steel pipe is more obvious.
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