It is well-known that the steel plate will deform in case of heat change. For steel structure, it is welded with section steel and steel plate, especially when it is less than 6mm thick, the deformation will be more severe. Then we should use press or heat to correct the deformation. For special-shaped steel structure, flame correction is generally adopted. There are three heating methods commonly used: point heating, linear heating and triangle heating. Generally, the heat correction deformation is only applicable to low carbon steel and Q345; for medium carbon steel, high alloy steel, cast iron and non-ferrous metal and other materials with high brittleness, cracks will occur due to cooling shrinkage deformation, so it is not allowed to use.
For heating correction, the heating temperature shall be well controlled, and the heating shall be uniform without overheating or overburning. The low alloy steel shall be cooled slowly to avoid cracks caused by excessive temperature difference between the steel surface and the internal. During the rectification, the workpiece shall be leveled, the cause of deformation shall be analyzed, the heating hot spot, heating temperature and heating area shall be selected correctly, and the heating times of the same heating hot spot shall not exceed 3 times.
1. The heating method of steel structure processing point is suitable for correcting the local bending or uneven of sheet metal. According to the structural characteristics and deformation conditions, one or several points can be heated.
2. Linear heating is often used to correct the angular deformation and local arc and bending deformation of structures or thick plates with large deformation or rigidity. During correction, the flame moves along a straight line or swings laterally in the width direction at the same time. The width is generally about 0.5-2.0 times of the steel thickness.
3. Triangle heating has a large amount of shrinkage, which is applicable to the correction of longitudinal bending and local bending deformation of section steel, steel plate and components (such as roof truss, crane beam and other finished products), and mostly used to correct the bending deformation of components with large thickness and strong rigidity.
For the correction of deformation, we should pay attention to that the heating deformation is usually used for the correction of black parts in the workshop, that is to say, before the anti-corrosion process, the heating correction, then for the steel structure after hot-dip galvanizing or paint spraying, it is necessary to use the manual method to correct, or make the mould to change another deformation method through one deformation.