When selecting square tubes, it's crucial to know where you plan to use the tube and then choose the appropriate method based on its intended use. If it's for decoration, opt for decorative housing square tubes. For mechanical or machine processing, select square tubes designed for machinery. For specialized applications, pick tubes tailored for those specific uses. Additionally, pay attention to the quality of the square tube and ensure the model matches your requirements.

When selecting square tubes, pay attention to their appearance for rust, the smoothness of the welds, the amount of burrs at the tube ends, and the straightness of the tubes (avoiding any crooked tubes). Also, check for the presence of joint tubes. If possible, measure the outer diameter and wall thickness of the square tubes, as well as their length to ensure they meet specifications.