There are several ways of electrogalvanizing, and what is the process flow?

Hot-dip galvanizing process:Workpiece: Degreasing, washing, pickling, washing, dipping solvent, baking, hot-dipping, galvanizing, finishing, cooling, passivation, rinsing, drying, inspection.

1. Degreasing: chemical degreasing or water** degreasing cleaning agent can be used to remove oil until the workpiece is completely soaked with water.

2 pickling: can be pickled with H2SO415%, thiourea, 40 60 or HCl20%, hexamethylenetetramine 1 3g L, 20 40. The addition of corrosion inhibitors can prevent over-corrosion of the matrix and reduce the amount of hydrogen absorbed by the iron matrix.

Poor degreasing and pickling treatment will cause poor adhesion of the plating layer, and the zinc layer will not be plating or the zinc layer will fall off.

There are several ways of electrogalvanizing, and what is the process flow?

Taking galvanized ferroalloy as an example, the process flow is as follows: chemical degreasing, hot water washing, water washing, electrodegreasing, hot water washing, water washing, strong corrosion, water washing, electrogalvanized ferroalloy washing, water envy washing, light out, passivation, water washing, drying. Plating solution preparation:

Preparation of plating solution (take LL as an example): add 1 3 volumes of pure water in the plating tank first; dissolve sodium hydroxide in pure water of 1 3 (it heats up when dissolved, care must be taken); Use a small amount of water to mix the zinc oxide into a paste, then add more pure water and stir thoroughly. The stirred zinc oxide is slowly added to the dissolved sodium hydroxide solution, stirred while adding, and then added to the plating tank after it is fully complexed; When the temperature of the plating solution drops below 30 C, add 85g of Baser and stir thoroughly. Dissolve 15 ml of BaseF in 15 g Baser and add its mixture to the plating tank; Add 4ml of H-O624 and stir thoroughly; Add water to the allocated volume; Add brighteners ZF-105A and ZF-105B; Stir thoroughly.

Black passivation process: washing, light, washing, black passivation, washing, post-treatment, drying.

<> electrogalvanizing is divided into two parts: galvanizing + passivation. If it is a high-strength material, it should be dehydrogenated within 4h of electrogalvanizing before passivation.

The process flow is as follows: parts hanging - organic solvent degreasing - hot water washing - chemical degreasing (or electrodegreasing) - washing - rust removal - washing - acid activation - washing - electroplating - washing - light - washing - passivation - washing - drying galvanizing after passivation should pay attention to: 1) the quality of the galvanized layer should be consistent.

2) High chromium passivation belongs to gas phase film formation, galvanized parts stay in the passivation solution for about 5-10s, stay in the air for about passivation, and the workpiece should be thoroughly cleaned after passivation. 4) After passivation, the workpiece should be baked and aged, and the baking temperature is generally not more than 65. 6.

Reasons for discoloration after galvanizing passivation: 1) The influence of galvanizing liquid system It is believed that ammonium salt is easy to change color after galvanizing passivation. 2) The influence of the thickness of the galvanized layer The thickness of the galvanized layer is too small, that is, the coating is too thin (such as less than 3 microns), and it is easy to change color after passivation.

There are many barrel-plated parts. 3) The influence of galvanizing solution maintenance Improper maintenance of the plating solution and excessive use of additives lead to excessive organic inclusions in the plating layer, which is easy to change color after passivation. 4) The impact of galvanizing layer cleaning After galvanizing, the cleaning is not bottomed, and the organic matter on the plating layer cannot be washed, and it is easy to change color after passivation.

Most of the equipment conditions are imperfect and manual operation. 5) The influence of impurities in the solution There are too many impurities in the galvanizing solution and passivation solution, and it is easy to change color after passivation. 6) The influence of the follow-up process of galvanizing passivation: For example, after passivation, the passivation film will change color after high temperature (such as dehydrogenation of the workpiece).

7) Other reasons: storage environment, combination or contact with other materials and plating will also affect the discoloration of the coating.

Summary. Process flow:

Taking galvanized ferroalloy as an example, the process flow is as follows:

Chemical degreasing, hot water washing, water washing, electric degreasing, hot water washing, water washing, strong corrosion, water washing, electrogalvanized ferroalloy, water washing, water washing, light out, passivation, water washing, drying.

Preparation of plating solution: Preparation of plating solution (take LL as an example):

Add 1 3 volumes of purified water to the plating tank first;

dissolve sodium hydroxide in pure water of 1 3 (it heats up when dissolved, care must be taken);

Use a small amount of water to mix the zinc oxide into a paste, then add more pure water and stir thoroughly. The stirred zinc oxide is slowly added to the dissolved sodium hydroxide solution, stirred while adding, and then added to the plating tank after it is fully complexed;

Process flow and formula of electrogalvanizing.

Process flow: Taking galvanized ferroalloy as an example, the process flow is as follows: chemical degreasing, hot water washing, water washing, electrodegreasing, hot water washing, water washing, strong corrosion, water washing, electrogalvanized ferroalloy washing, water washing, light out, passivation, water washing, drying.

Preparation of plating solution: Preparation of plating solution (take LL as an example): 1 3 volumes of pure water are added to the plating tank first; dissolve sodium hydroxide in pure water of 1 3 (it heats up when dissolved, care must be taken); Use a small amount of water to mix the zinc oxide into a paste, then add more pure water and stir thoroughly.

The stirred zinc oxide is slowly added to the dissolved sodium hydroxide solution, stirred while adding, and then added to the plating tank after it is fully complexed;

When the temperature of the plating solution dropped to below 30 C, 85g of Baser was added and stirred thoroughly. Dissolve 15 ml of BaseF in 15 g Baser and add its mixture to the plating tank; Add 4ml of H-O624 and stir thoroughly; Add water to the allocated volume; Add brighteners ZF-105A and ZF-105B; Stir thoroughly. Black passivation process: washing, light, washing, black passivation, washing, post-treatment, drying.

Hot-dip galvanizing formation principle:

The process of forming an iron-zinc alloy between the iron matrix and the outermost pure zinc layer, the iron-zinc alloy layer is formed on the surface of the workpiece during hot-dip plating, so that the iron and the pure zinc layer are well combined, and the process can be simply described as: when the iron workpiece is immersed in molten zinc, a zinc and iron (body-centered) solid melt is first formed at the interface. This is a crystal formed by the dissolution of zinc atoms in the solid state of the base metal iron, and the gravitational force between the two metal atoms is relatively small.

Therefore, when the zinc reaches saturation in the solid melt, the atoms of the two elements of zinc and iron diffuse each other, and the zinc atoms diffused into (or infiltrated) the iron matrix migrate in the matrix lattice and gradually form an alloy with iron, and the iron diffused into the molten zinc liquid forms an intermetallic compound FEZN13 with zinc, which sinks to the bottom of the hot-dip galvanizing pot, which is zinc slag. When the workpiece is removed from the zinc-impregnated liquid, a pure zinc layer is formed on the surface, which is a hexagonal crystal of Tongtong. Its iron content is not greater than.

Raw material galvanizing distinction :

1.Hot-dip galvanized (the surface is gray).

2.Electrogalvanized (the surface is zinc-colored).

Parts galvanized differentiated:

1.Electrogalvanizing : electrochemical process.

2.Mechanical galvanizing: mechanical process.

Electro-galvanizing is distinguished in the operation process

1.Hanging galvanized.

2.Roll galvanized.

Electrogalvanizing is distinguished in chemical solutions:

1.Acid galvanized :(further divided into potassium and ammonium) 2.Alkaline galvanizing :(then divided into cyanide, and non-cyanide) electrogalvanizing is distinguished in environmental protection

1.Trivalent chromium is environmentally passivated.

2.Hexavalent chromium is not environmentally friendly passivation.

Electrogalvanized is distinguished in passivation color:

1.Color passivation.

2.Natural color passivation (white passivation).

3.Blue passivation.

4.Black passivation.

5.Green passivation.