Leakage plating means that the galvanized layer intermittently shows black spots with irregular spots or irregularities. When the surface of the steel strip contains dirt, it interferes with the infiltration of the zinc liquid and affects the galvanizing reaction. The main causes of zinc leakage are:
1. Substrate surface adheres to foreign objects that have not been cleaned. This type of leaky plating defects may be distributed on the lower surface or upper surface of the steel strip, and generally show an irregular pattern of block marks. Cause: The emulsion on the surface of the substrate is not uniform, or there is residual rolling oil on the surface of the substrate. Solid contaminants such as iron powder produced by the deformation and wear of the substrate will contaminate the surface of the substrate. If these are cleaned during the galvanizing line, Impurity removal is not clean, it will lead to some of the contaminants in the galvanizing process of the strip can not be infiltrated by the zinc liquid, prone to leak plating.
2. The oxide layer is not effectively reduced before it enters the zinc pot. This zinc leakage defect will be distributed on the lower or upper surface of the galvanized sheet. If a horizontal furnace is used, the underplating defects on the lower surface may be lower than the upper surface. The more serious, the same showing a distribution of irregularities, and the defect morphology is generally a sheet of pinhole black spots. Cause: In the process flow, the annealing section is mainly used to eliminate work hardening, ensure the substrate recrystallizes and enters into the zinc pot, and at the same time reduces the surface of the strip. In the reducing furnace, nitrogen and hydrogen protective gas are introduced to make the atmosphere in the furnace a reducing atmosphere. If the oxide layer cannot be effectively reduced before entering the zinc pot, the wettability of the zinc liquid to the substrate is reduced, and zinc leakage is easily occurred. defect.
3. Refractory material stripping affects the surface quality of the galvanized layer. This zinc leaching defect may be distributed on the lower surface or the upper surface of the galvanized sheet, and is longitudinally distributed along the running direction of the strip. The morphologies are strips. Cause: It is easy to cause flaking of refractory material during the process of furnace opening and furnace shutdown. If the tiny particles of refractory material fall on the surface of the steel plate or the working surface of the roller, it will affect the quality of the galvanized sheet. However, if there is dust on the zinc surface of the internal surface of the nose, normal operation between the zinc ash and the strip will maintain a certain safety distance during the normal operation of the strip. At this time, there will be no leakage plating defects; however, if the strip steel generates vibration And the amplitude is greater than the distance between the strip and the zinc ash, the zinc ash will adhere to the surface of the strip, reduce the wettability of zinc liquid to the substrate, resulting in the defects of the leakage plating. For this reason, refracting delamination should be avoided during production to ensure that the furnace gas control in the annealing furnace satisfies the process requirements, the cleanliness of the galvanized front surface of the strip steel is improved, and the zinc oxide content of the zinc liquid is regularly cleaned to avoid the hot galvanized steel strips from leaking zinc. , produce high quality products.
Wire Spring,Double Torsion Spring Design,Spring Steel Wire,Stainless Steel Spring Wire
OEM order and ODM order can is welcome
wire thickness : 0.07--5mm
applicaiton: viation,automotive, motorbike, bicycle, automatic equipment, household appliance, medical device ,toy, telecommunication,computer, instrument and meter,furniture, electric tools,mold and other industries
Wire Spring,Double Torsion Spring Design,Spring Steel Wire,Stainless Steel Spring Wire
Shenzhen Lanejoy Technology Co.,LTD , https://www.ccls-vaccine.com