Why do hazardous chemical storage cabinets made of galvanized steel require more precise welding processes to prevent weld corrosion?
Publish Time: 2025-10-30
In the design and manufacture of hazardous chemical storage cabinets, material selection and process precision directly affect the equipment's corrosion resistance, safety, and service life. Currently, high-quality hazardous chemical storage cabinets commonly use galvanized steel as the main structural material because its surface is covered with a zinc protective layer, providing excellent corrosion resistance and effectively resisting the erosion of chemical vapors such as acids, alkalis, and solvents. However, it is precisely the special nature of this galvanized material that places higher demands on the precision of the welding process during its processing. Improper welding can not only compromise the overall protective performance but may also become the starting point for corrosion.1. Risk of Damage to the Galvanized Layer During WeldingThe corrosion protection principle of galvanized steel is based on the "sacrificial anode" mechanism: zinc has higher electrochemical activity than iron, and when electrolytes are present in the environment, zinc will preferentially corrode to protect the internal steel. However, during welding, the high-temperature electric arc can cause the zinc layer in the weld area to vaporize and burn away instantly, forming a localized "dezinc-depleted zone." If the welding process is rough, the heat control is uneven, or the weld is discontinuous, it will cause large-area damage to the zinc layer, exposing the base steel and leaving the area around the weld without cathodic protection, making it extremely vulnerable to corrosion.2. Multiple Corrosion Hazards Caused by Poor WeldingTraditional rough welding processes often produce defects such as weld slag residue, porosity, lack of fusion, and undercut. These microscopic uneven areas easily accumulate chemical vapors, condensate, or residual liquids, forming localized corrosion cells. Especially in environments storing acidic or saline chemicals, the long-term action of humid air and corrosive gases on the weld will accelerate the electrochemical corrosion process, leading to weld cracking, rust penetration, and even leakage risks. Furthermore, zinc oxide dust generated at high temperatures is toxic, and poor ventilation during welding can also pose occupational health hazards.3. How to Ensure Integrity with Precision Welding TechnologyTo solve the above problems, modern high-end hazardous chemical storage cabinets employ advanced technologies such as precision resistance welding, laser welding, or automated pulsed MIG welding. These processes feature controllable heat input, uniform penetration, and narrow, smooth welds, minimizing the heat-affected zone and reducing zinc layer burn-off. Simultaneously, precision welding achieves a smooth transition without weld beads, burrs, or abnormal edges, avoiding stress concentration and contaminant accumulation. Post-weld grinding and leveling ensure the weld area is flush with the base material surface, providing a consistent adhesion base for subsequent spraying.4. Synergistic Protection of Surface Treatment and CoatingEven with precision welding, zinc layer loss still exists in the weld area. Therefore, surface pretreatment is necessary to enhance metal surface activity, followed by the application of a high-adhesion epoxy primer and a chemical-resistant topcoat, forming a dense coating barrier. Only with precise welding and a smooth, bump-free surface can the spraying process achieve a uniform, scratch-free, bubble-free, and thickness-consistent coverage, truly realizing integrated corrosion protection between the weld and the overall cabinet.In conclusion, while galvanized steel sheets possess excellent corrosion resistance potential, the destructive nature of the zinc layer during welding necessitates the reliance on precision welding processes to maintain structural integrity. Only by using advanced technology to achieve precise welding, smooth surfaces, and no abnormal edges can we ensure that the weld area does not become a breakthrough point for corrosion, thereby leveraging the synergistic protective advantages of galvanized steel sheets and surface spraying processes to guarantee the long-term safe and reliable operation of hazardous chemical storage cabinets in harsh environments.
