1, deep processing: easy to produce friction heat, so the use of high-pressure, high heat-resistant square tube at the end of the formation should be removed surface attached to the oil. Square pipe welding: Before welding should remove welding rust, oil, water, paint and other steel electrode. The spot welding time is shorter than the spot welding distance of carbon steel, the square pipe brush is used. After welding, the surface is treated or cleaned to prevent local corrosion or strength reduction. 2. Cutting and punching: Because the general strength of the square pipe is higher than that of the material, stamping and shearing require higher pressure, while the knife and knife clearance are inaccurate, shear damage and work hardening can not occur, using plasma or laser cutting, when using gas cutting or cutting, heat-affected zone grinding and necessary heat treatment.