22. What problems are likely to occur in the production of high-frequency welded square pipes? How to solve it?

22.1. R Angle Cracking
22.1.1. Material selection and quality control
Choose high-quality materials: ensure that the selected square tube materials are of high quality, and avoid using hot-rolled plates with excessive original cracks or inclusions.
Enhanced Material Testing: Conduct rigorous testing before materials are put into storage, including chemical composition analysis, metallographic observation, etc., to rule out potential quality issues.
22.1.2. Optimization of production process
Improve welding process: For welded square pipes, optimize welding parameters such as current, voltage, welding speed, etc., to ensure weld quality and reduce the risk of welding stress and cracks.
Optimize the bending process: During the bending process, reasonably control the bending angle and force to avoid excessive stress concentration at the R angle. Consider using multi-pass bending or pre-bending treatments to disperse stress.
Heat treatment: For square tubes that require heat treatment, strictly control the heating temperature and holding time to avoid overheating leading to degradation of material properties or new cracks.
22.1.3. Design and structural improvement
Enhance R-angle structure: When designing square tubes, consider adding stiffeners or using thicker materials at R-angles to improve the strength and rigidity of R-angles and reduce the risk of cracking.
Optimize the force distribution: Optimize the force distribution and reduce the stress concentration at the R angle by reasonably designing the support structure and connection method of the square tube.
22.1.4. Post-processing and maintenance
Surface treatment: Surface treatment of square pipes, such as sandblasting, painting, etc., to improve their corrosion resistance and fatigue resistance.
Regular inspection and maintenance: During use, regularly inspect and maintain the pipe to detect and deal with cracks and other defects in a timely manner to prevent the problem from expanding.
22.2. Distortion
22.2.1. Optimization of production processes
Rotary wheel operation: reduce the length of the overhanging end of the thick-walled square pipe on the rotating wheel, and control it within a reasonable range (such as ≤ 600mm) to reduce the centripetal force during heat treatment, thereby reducing the twist. Additionally, adjust the rotating wheel speed ratio and core position to ensure stability and uniformity during rotation.
22.2.2. Equipment Maintenance
Regularly maintain and maintain production equipment to ensure that the equipment is in good condition and avoid machining errors and distortions caused by equipment failure or reduced accuracy.
22.2.3. How to correct?
Hydraulic straightening method, pressure reverse topping method, heating straightening method, manual straightening method, etc.