Hot-dip galvanized base alloy ammonium fluxing agent process and principle

With the gradual improvement of the people's awareness of environmental protection and the state increasingly stringent environmental requirements, the batch hot dip galvanized zinc traditional - ammonium fluxing process to produce large amounts of exhaust gas and soot due to the decomposition of ammonium chloride in high temperature conditions can not meet the hot-dip galvanizing industry clean production requirements. Development of environment-friendly no ammonium low smoke fluxing agent is the main direction of the current batch hot dip galvanized research and development. Domestic and foreign scholars and engineers to reduce environmental pollution for the purpose, a series of studies on the composition of the fluxing agent and fluxing process, but not a new fluxing process can completely replace the traditional zinc - ammonium fluxing processes. This article is based on the study batch hot-dip galvanized ammonium fluxing process on the basis of written application of single factor test and orthogonal test, Design-Expert 6.0 trial design and factory test a combination of research methods, fluxing process recipe research and validation, preferably a non-ammonium help plated new formula, no ammonium fluxing need to meet the physical conditions of the Ammonium-fluxing mechanism. Ammonium fluxing process of process parameters, the range of applications and its impact on the microstructure and properties of the coating were carried out. Finally, the ammonium fluxing process reliability and stability analysis and evaluation; conduct a comprehensive assessment of its economic and environmental benefits arising. The study showed that: abandoned the traditional zinc ammonium chloride - ammonium fluxing agent component, using a fluorine - carbon chain and carbon - hydrogen chain surfactant mixture to form a compound surfactant Fc ZnCl2-NaCl-NaF multiplexed no ammonium salt system fluxing agent, can replace the traditional zinc factory small batch verification - ammonium fluxing process. Ammonium fluxing agent optimal formula: the zinc chloride the 19.16R g / L sodium chloride 5.07R g / L, sodium fluoride 3.48R g / L, FC 5.9ng / L. The process has a high reliability and stability, wide temperature range, also can be used normally under room temperature conditions; balanced by the system and can be maintained in the solvent pH value is lower, a higher content of free acids under conditions obtained plated coating seamless phenomenon. No ammonium allowed the presence of ferrous ion content than traditional fluxing agent; fluxing agent and can, under the conditions of high humidity environment, coated hanging after a certain time to get a good coating. No ammonium the fluxing process can not change the traditional zinc - ammonium fluxing process production processes, equipment and layout of the conditions for the substitution of zinc - ammonium fluxing process-dip process the soot emissions zinc - ammonium fluxing process reduced by 70% Ammonium-fluxing process not only greatly reduce the pollution of the environment, but also the resulting coating organization can be refined, can improve the corrosion resistance of the coating. Pure zinc coating grain size zinc - ammonium fluxing conditions ammonium help plated 1.5 times; Zn.0.05% Al coating the grain size is ammonium help plated 1.2 times; pure zinc coating and corrosion resistance zinc - ammonium fluxing increased by approximately 10%; Zn-0.05% Al coating corrosion resistance than zinc - ammonium fluxing increased by 40%. Zinc coating thickness obtained in the ammonium fluxing conditions - ammonium help plated the slightly thin tendencies, but stable aluminum better. Fluxing agent component ammonium surfactants Fc plays an important role to improve the wetting properties and thickness of the coating of the workpiece and the liquid alloy interface, zinc chloride significant effect on the thickness of the coating and the drain plating rate Chloride sodium on the surface quality of the coating. Fluxing agent sodium ions and the synergistic effect of the surfactant Fc fluxing effect evaluation is more significant. As hot-dip ammonium fluxing agent that must be met: sigma iron - melting gt; flux of the sigma iron - zinc adhesion; the flux temperature should be lower than the temperature of the hot-dip galvanized, hot-dip galvanized should be Movement of the molten state.