Chemical Industry - Corrosive Media Conveying

In the acid-alkali storage, transportation, and reaction sections of chemical plants, DN chains serve as critical transmission components for reactor hoisting and pipeline valve actuation, where their performance directly dictates the sealing integrity and intrinsic safety of the production system. The surface galvanizing process employs hot-dip galvanizing technology to form a zinc-iron alloy layer with a thickness of ≥85μm. This layer not only isolates corrosive media via a physical barrier but also utilizes the anodic protection characteristics of zinc to safeguard the base steel in the event of localized coating damage. Furthermore, the alloy strengthening treatment optimizes the steel's microstructure by adding elements such as nickel and molybdenum. This elevates the base hardness to over HRC35 and pushes tensile strength beyond 1000MPa, ensuring structural integrity even under alternating erosion from strong acid vapors and alkaline liquids.

To combat strong corrosive media like hydrogen sulfide and chloride ions, the chain links are manufactured using full-penetration welding. The welds undergo dual verification via X-ray radiography and penetrant testing to ensure the absence of defects such as porosity or cracks. In reactor hoisting scenarios, where chains bear dynamic loads of 5-10 tons, their low-deformation characteristic stems from precision quenching and tempering. By controlling the hardening temperature and tempering time, the links achieve a uniform tempered sorbite microstructure with a stable elastic modulus exceeding 200GPa. Consequently, even in high-temperature acidic or alkaline environments (up to 150°C), the permanent deformation rate remains below 0.2% after long-term service, effectively preventing valve seat misalignment or reactor tilting caused by chain elongation.

To meet the zero-leakage requirements of chemical processes, the connection between the DN chains and valve transmission mechanisms utilizes a combination of prevailing torque threads and elastic washers. Coupled with regular torque inspections, this prevents loosening induced by vibration. In chlor-alkali production units, the chains are further coated with a composite system of zinc-rich epoxy primer and polyurethane topcoat. Validated by 500-hour salt spray tests, this corrosion resistance is three times superior to standard galvanized chains. Even in extreme environments ranging from pH 1 to 14, the chains maintain transmission precision and sealing reliability, providing solid support for the safe and stable operation of chemical production.