(1) The reliability of high-precision square pipe specifications stipulates that the precision of pipe fittings should be maintained for a long time. Due to the low cooling rate and straightening in the air, it has a smooth effect and increases the number of residual square tubes in the structure, so it is necessary to carry out cold violence.

(2) Due to the slenderness of the rectangular tube, reducing heat treatment deformation is easy to deform, and the deformation must be strictly controlled during the heat treatment process. The heat treatment process is a very important whole process. In the process of heat treatment and refrigeration, the use of cold plastic deformation for direct calibration is an important factor to ensure the improvement of the compliance rate. Therefore, heat treatment in a hot bath or heat treatment in oil should be carried out. The substance is refrigerated for a certain period of time, proposing a thermal calibration.

At the same time, suspension heating should be carried out during the heating process to reduce heat treatment deformation. For high-precision slide rails, gas high-frequency quenching or low-temperature plasma high-frequency quenching should be carried out to reduce deformation.

(3) High-toughness square tubes are mainly affected by contact fatigue loads, so they must have high toughness. Therefore, heat treatment, induction hardening, or organic chemical heat treatment should be carried out, followed by low-temperature quenching.