Method of straight seam steel pipe in preheating deformation

1. Reasonable selection of materials.

For precision messy molds, micro-deformed mold steel of good quality should be selected. For mold steel with serious carbide segregation, reasonable casting and quenching and tempering heat treatment should be carried out. For larger and unsuitable mold steel, solid solution double refinement heat treatment can be carried out. Reasonably select the heating temperature and control the heating speed. For precision and messy molds, slow heating, preheating and other balanced heating methods can be used to reduce mold heat treatment deformation.

2. Correct heat treatment process operation and reasonable tempering heat treatment process are also useful methods to reduce the deformation of precision messy molds.

The reason for the deformation of the precision messy mold is often messy, but only need to grasp the deformation rules, analyze the cause of its occurrence, and choose an abnormal method to avoid the deformation of the mold, which can be reduced and controlled.

3. Pre-heat treatment of precision messy molds should be carried out to eliminate the remaining stress during machining.

For precision messy molds, when conditions permit, try to use vacuum heating and quenching and cryogenic treatment after quenching. On the premise of ensuring the hardness of the mold, try to use pre-cooling, staged cooling quenching, or warm quenching processes.

4. Mold planning and description should be reasonable, the thickness should not be too wide, the shape should be symmetrical, the deformation rules should be mastered for the larger deformed mold, and the processing allowance should be reserved. The large, precise, and a messy mold, combine planning can be used.

For some precision and messy molds, pre-heat treatment, aging heat treatment, and tempering and nitriding heat treatment can be used to control the accuracy of the mold. When repairing mold blisters, pores, wear, and other defects, use cold welders and other equipment with low heat impact to avoid deformation during the repair process.