In practice, the corrosion or discoloration of large rolls of galvanized wire in the atmosphere due to oxygen, moisture and other pollution impurities is called rust or rust. After the metal products rust, the light will affect the appearance quality, the serious will affect the use, and even cause scrap, so the metal products in custody, must be properly kept, pay attention to rust prevention.
When the atmospheric humidity is higher than the critical humidity, there will be water film or water beads on the metal surface, if the harmful impurities contained in the atmosphere are dissolved in the water film, water beads, that is, electrolyte, aggravate rust. Large roll galvanized wire has good toughness and elasticity, the amount of zinc can reach 300 grams/square meter, and has the characteristics of thick galvanized layer and strong corrosion resistance. Widely used in construction, handicrafts, wire mesh, highway guardrail, product packaging and daily civilian and other fields.
Large roll galvanized wire is made of high quality low carbon steel wire processing, galvanized wire is divided into hot galvanized wire and cold galvanized wire (electric galvanized wire) is the use of high quality low carbon steel, after drawing forming, pickling rust, high temperature annealing, hot galvanized. Cooling and other process processing. Galvanized wire mesh specifications are complete, variety, suitable for urban traffic arteries, highways in the middle of the green isolation belt, Bridges, secondary highways, township roads and highway tolls and other isolation.
Galvanized wire mesh surface smooth, high strength, toughness, corrosion resistance, UV resistance, no fading, no cracking, no embrittlement advantages, become the decorative effect of the guardrail boutique. The coating is rough and the passivation film is not bright. The bath temperature is too high, the cathode current density is too large, the zinc content in the bath is too high or the sodium hydroxide and DPE content is too low, there are solid particles or excessive metallic impurities in the bath, etc., will cause this kind of failure.
When analyzing the fault, first observe the phenomenon, if the plating part is rough to the upper coating, it may be that there are solid particles in the plating solution. If the edge and tip of the part are rough, it may be that the current density is too large. If the galvanized layer is good, but when the light comes out in 3% nitric acid, there is a black shadow on the coating, and the film layer appears brown when passivated, which may be that there are foreign metal impurities such as copper or lead in the galvanized liquid.
When this kind of failure occurs, first check the temperature and current density, and then through the plating solution analysis, determine and adjust the content of zinc and sodium hydroxide in the plating solution, whether the DPE content is low, can be understood through the Hull tank test. If the rough coating is not caused by the above reasons, it may be caused by impurities in the plating solution, you can take a small amount of plating solution, after filtration test, and then take a small amount of plating solution, after zinc powder treatment test, check whether the fault is caused by solid particles or copper, lead and other metallic impurities, one by one test, the cause of the fault is not difficult to find.
Post time: 19-10-23