Seamless square tube is a kind of long steel with hollow section without joints. The pipe is hollow, with a certain cross-sectional area, and a large number of pipes are used for conveying fluid, such as those for transporting oil, natural gas, gas, water and some solid materials. When the circular section bears internal or external radial pressure, the force is relatively uniform. Therefore, most of the steel pipes are circular. However, the circular pipe also has some limitations. For example, under the condition of plane bending, the bending strength of the circular pipe is not as strong as that of the square and rectangular pipes. Some agricultural machinery frameworks, steel and wood furniture are commonly used square and rectangular pipes