The welding process of metal coat racks is a core element in ensuring their connection strength, directly affecting the product's structural stability and lifespan. In the production of metal coat racks, welding requires a multi-dimensional collaborative approach, including material matching, process optimization, equipment control, and quality inspection, to ensure that the weld strength meets or exceeds the base material's standards, thereby satisfying the load-bearing and deformation resistance requirements of daily use.
Material selection is fundamental to the welding process. Metal coat racks commonly use materials such as stainless steel, carbon steel, or aluminum alloys. The chemical composition and physical properties of different materials directly affect the welding effect. For example, stainless steel has a high chromium content and strong corrosion resistance, but heat input must be controlled during welding to avoid intergranular corrosion; carbon steel requires adjustments to the welding wire composition (such as adding deoxidizers like manganese and silicon) to reduce the risk of porosity and cracking. Matching the material thickness is equally crucial; materials that are too thin are prone to deformation due to welding heat, while materials that are too thick may fail to fuse due to insufficient heat input. Therefore, before welding, welding wire or electrodes with a composition similar to the base material must be selected according to design requirements to ensure the metallurgical compatibility of the weld metal and the base material.
Precise control of welding process parameters is crucial for ensuring joint strength. Welding current, voltage, speed, and heat input must be dynamically adjusted according to material thickness and joint type. For example, when welding thin-walled pipes, a low current and high-speed welding are required to reduce the heat-affected zone and prevent burn-through or deformation; thick-plate welding requires increased current and multi-layer, multi-pass welding to ensure sufficient penetration. The design of the welding sequence is also critical. Symmetrical structures should use a symmetrical welding sequence to balance welding stress and reduce deformation; asymmetrical structures should start welding from the more rigid side and gradually move towards the free end to prevent cracking due to stress concentration.
The selection of welding equipment and auxiliary tools directly affects process stability. Automated welding equipment (such as robotic welding workstations) can achieve precise parameter control through preset programs, reducing human error, and is particularly suitable for mass production. For complex structures or small-batch products, manual welding requires auxiliary tools such as jigs and fixtures to fix the workpiece position and control welding deformation. For example, when welding pipe joints with a coat rack using a rotating jig, the rotation function of the jig can achieve 360-degree uniform welding, avoiding stress concentration caused by localized overheating.
The design of welded joints must balance strength and process feasibility. Butt joints are the ideal joint type in coat rack structures due to their low stress concentration, especially suitable for connecting pipes and plates. T-joints require beveling designs (such as V-grooves) to increase penetration depth and ensure complete fusion at the weld root. For space-constrained scenarios or those requiring rapid assembly, fillet welds can be used, but strength loss must be compensated for by increasing the weld leg size or using double-sided welding. Furthermore, rounded corners at joint transitions can reduce stress concentration and improve fatigue life.
Defect control during welding is crucial for ensuring strength. Defects such as porosity, cracks, and undercut significantly reduce the effective cross-sectional area of the weld, leading to stress concentration. For example, porosity reduces the actual load-bearing area of the weld metal, while cracks can become the starting point for fatigue failure. Therefore, strict control of shielding gas flow rate (e.g., argon purity ≥99.99% in TIG welding), welding speed, and interpass temperature is necessary during welding to avoid defects caused by poor weld pool protection or overheating. Post-weld inspection, including visual inspection, penetrant testing, or X-ray inspection, is required to ensure the weld quality meets standards.
Post-weld treatment processes play a crucial role in improving connection strength. For coat racks subjected to dynamic loads (such as foldable models), stress-relief annealing is necessary after welding to eliminate residual welding stress and prevent deformation or cracking during use due to stress release. Surface treatment processes (such as polishing and sandblasting) remove oxide scale and burrs from the weld surface, reducing the risk of stress concentration and improving the product's appearance.
The welding process for metal coat racks requires a multi-faceted approach, including material matching, parameter control, equipment optimization, joint design, defect prevention, and post-weld treatment, to ensure weld strength and structural stability. This process demands not only precise welding techniques but also a balance between functionality and reliability, taking into account product design requirements and usage scenarios.
