Slide Switch Bezel,Alps Slide Switch,Slide Switch Common,Sliding Action Switch DA CHENG MINGHUA LIMITED , https://www.alpsswitch.com
Fence board manufacturers price process:
Shaped Guardrail → Degreasing → Washing → Pickling → Washing → Plating Solvent → Drying Preheating → Hot dip galvanizing → Finishing → Cooling → Passivation → Rinse → Drying → Inspection Related Process Description 1. Degreasing can be done using chemistry Remove oil or water-based metal degreasing cleaning agent to oil, until the guardrail is completely infiltrated with water.
2. Pickling can be H2SO415%, thiourea 0.1%, 40 ~ 60 °C or with HCl 20%, hexamethylene tetramine 1 ~ 3g / L, 20 ~ 40 °C pickling. The addition of a corrosion inhibitor can prevent excessive corrosion of the matrix and reduce the amount of hydrogen absorbed by the iron matrix.
Degreasing and pickling will not result in poor adhesion of the coating, and the coating will not be detached from the zinc or zinc layer.
3. The immersion plating agent, also called bonding agent, can maintain certain activity before the immersion plating of the guardrail to enhance the bond of the plating to the substrate. NH4Cl15%-25%, ZnCl22.5%-3.5%, 55-65°C, 5-10 min. To reduce the volatilization of NH4Cl, glycerol may be added as appropriate.
4. Drying and preheating In order to prevent the waveform guardrail from deforming due to the sharp rise in temperature during immersion plating, and removing residual moisture to prevent the generation of burst zinc, the zinc liquid splashes, and the preheating is generally 120-180°C.
5. Hot-dip galvanizing It is necessary to control the temperature of the zinc bath, the immersion plating time, and the speed at which the guardrail board is removed from the zinc bath.
The temperature is too low, the zinc liquid is poor in fluidity, the coating thickness is thick and uneven, sag is easy to occur, and the appearance quality is poor. The temperature is high, the zinc liquid is good in fluidity, and the zinc liquid is easily detached from the guardrail board to reduce the sag and wrinkle phenomenon. Strong, thin coating, good appearance, high production efficiency; but the temperature is too high, guardrail and zinc pot iron loss is serious, resulting in a lot of zinc slag, affecting the quality of zinc leaching layer, zinc consumption, or even plating.
At the same temperature, the immersion plating time is long and the plating thickness is thick. Different temperatures, when the same thickness is required, high-temperature immersion plating takes a long time.
General manufacturers in order to prevent high temperature deformation of the guardrail and reduce the zinc slag caused by iron loss, are used 450 ~ 470 °C, 0.5 ~ 1.5min. Some factories use high temperatures for guardrails, but they must avoid the peak temperature range of iron loss.
In order to improve the fluidity of the hot-dip bath at lower temperatures, to prevent excessive plating, and to improve the appearance of the coating, 0.01 to 0.02% pure aluminum is often added. Aluminum is added in small quantities several times.
6. After finishing the plating, the finishing of the guardrail board is mainly to remove the surface residual zinc and zinc tumors, and it can be done by vibration or manual methods.
7. The purpose of passivation is to improve the resistance to atmospheric corrosion of the surface of the guardrail, reduce or prolong the appearance of white rust, and maintain the coating with a good appearance. Chromate is used to passivate, such as Na2Cr2O780 ~ 100g / L, sulfuric acid 3 ~ 4ml / L.
8. Cooling is generally water-cooled, but the temperature should not be too low to prevent the formation of matrix cracks in the guardrail panels, especially the castings due to chilled retraction.
9. Verify the appearance of the coating is bright, meticulous, free from sagging and wrinkled skin. Thickness test can use coating thickness gauge, the method is relatively simple. The coating thickness can also be converted by the zinc deposition amount. Bonding strength can be used bending press, sample 90 ~ 180 ° bending, should be no cracks and coating off. Heavy hammer percussion tests can also be used.
Galvanizing is also called hot-dip galvanizing and hot-dip galvanizing. It is an effective metal anti-corrosion method and is mainly used in metal structure facilities in various industries. The rust-removed steel part is immersed in a zinc liquid that is melted at about 500° C., so that a zinc layer is attached to the surface of the steel member, so that the purpose of corrosion protection is achieved. Hot dip galvanizing process: Finished pickling - Washing - Adding plating solution - Drying - Hanging plating - Cooling - Chemicals - Cleaning - Grinding - Hot dip galvanized finish 1. Hot dip galvanizing is developed by the older hot plating method Since 1836, France has used hot-dip galvanizing in industry for more than 170 years. In the past 30 years, with the rapid development of cold-rolled strip steel, the hot-dip galvanizing industry has been developed on a large scale.