The production and manufacturing of hot-dip galvanized cable trays is a systematic project, covering multiple key links, each of which is closely related and affects the quality of the final product. The specific process is as follows:
Hot-dip galvanized cable trays mainly use Q235 low-carbon steel as the production raw material. With its low cost and good plasticity, it has become the first choice for manufacturing. After the steel enters the site, it needs to be strictly tested by professional testing equipment for cracks, rust, carbon content, sulfur and phosphorus content and other key indicators to ensure that it fully complies with national standards. Only qualified steel will be accurately cut into bottom plates, side plates, cross bars and other parts according to the bridge design drawings using shearing machines, CNC cutting machines and other equipment. The cutting accuracy is strictly controlled within ±1mm to lay a solid foundation for subsequent production.
First, the cut parts are finely processed using stamping dies to produce connection holes, heat dissipation holes and other structures to ensure that the holes are accurately positioned and the edges are smooth. Subsequently, with the help of a bending machine, the steel plate is bent into a U-shaped, trough-shaped or tray-shaped bridge main structure according to the design requirements. The bending angle must strictly meet the standards to avoid deformation due to stress concentration. Then, the various components are assembled into a bridge using welding processes such as carbon dioxide gas shielded welding and arc welding. During the welding process, the current and welding speed must be accurately controlled to ensure that the weld is full and to prevent false welding and leaking welding. After welding, the bridge is fully deburred and polished to eliminate surface welding slag and sharp edges to prevent scratches on cables or operators during use. Finally, the pre-assembly and correction process is carried out to carefully check whether the bridge size is consistent with the drawing. If there is any deformation, it should be adjusted and repaired in time.
This is a key link in determining the corrosion resistance of the bridge. The first step is degreasing. The bridge is immersed in an alkaline solution such as sodium hydroxide or sodium carbonate, or ultrasonic cleaning is used to thoroughly remove surface oil, grease and lubricants to create conditions for the galvanized layer to be firmly bonded to the substrate. The second step is pickling. Put the bridge into hydrochloric acid or sulfuric acid solution to remove surface oxide scale, rust and other impurities. The pickling time is strictly controlled within 5-15 minutes according to the℃of steel corrosion to prevent excessive corrosion. After pickling, rinse repeatedly with clean water to remove residual acid, and then immerse in sodium carbonate solution for neutralization. Subsequently, immerse the clean bridge in molten zinc liquid at 450-480℃ for 3-5 minutes (adjusted according to the thickness of the steel) to make the zinc liquid react with the steel to form a zinc-iron alloy layer and a pure zinc layer on the surface. The alloy layer thickness of the bridge for outdoor use is generally 60-80μm, and that for indoor use is 30-50μm. After galvanizing, it is cooled to room temperature by air or water. Some processes will also perform chromate passivation treatment to further improve the surface gloss and salt spray resistance, so that the bridge can withstand salt spray for more than 1000 hours without red rust.
Quality inspection runs through the entire production process. During the appearance inspection, carefully check whether the bridge surface is smooth and uniform, whether there are defects such as missing plating, zinc nodules, bubbles, scratches, etc. The qualified galvanized layer should be silvery white or slightly blue, without obvious color difference; use a magnetic thickness gauge to accurately measure the thickness of the galvanized layer to ensure that the average thickness meets the standard and the local thickness is not less than 80% of the standard value; test the adhesion of the coating by the grid method and hammer method to ensure that the coating is tightly combined with the substrate without falling off or peeling off; in addition, random sampling will be carried out to test the load capacity to simulate the actual load conditions and check whether the bridge is deformed or broken to ensure that it meets the design load requirements.
The bridge that passes the quality inspection will first be subjected to the final deep cleaning to remove residual stains on the surface. In order to prevent bumps and moisture during transportation and storage, anti-rust oil will be applied to the surface or plastic film will be wrapped for protection if necessary. Then, according to different specifications and models, the bridges are classified and packaged in wooden boxes, cartons or pallet bundling. After packaging is completed, we will attach product certificates, detailed test reports and other documents, clearly marking information such as brand, model, material, implementation standard, production date, etc. to facilitate customer acceptance and quality traceability.