Hot-dip galvanizing angle steel process: angle steel pickling → water washing → immersion assisted plating solvent → drying preheating → hanging plating → cooling → passivation → cleaning → grinding → hot galvanizing completed. The galvanized layer of hot-dip galvanized angle steel has a uniform thickness of 30-50um, and the reliability is good. The galvanized layer and the steel are metallurgically combined and become a part of the steel surface, so the coating of the hot-dip galvanized angle steel is more durable. .
1. Hot-dip galvanized angle steel is also called hot-dip galvanized angle steel or hot-dip galvanized angle steel. The rust-removed angle steel is immersed in a zinc solution melted at about 500 ° C to adhere the zinc layer to the surface of the angle steel, thereby preventing the corrosion, and is suitable for use in various strong corrosive environments such as strong acid and alkali mist.
Angle steel pickling - washing - dip assisted plating solvent - drying preheating - hanging plating - cooling - passivation - cleaning - grinding - hot galvanizing completed. The galvanized layer of hot-dip galvanized angle steel has a uniform thickness of 30-50um, and the reliability is good. The galvanized layer and the steel are metallurgically combined and become a part of the steel surface, so the coating of the hot-dip galvanized angle steel is more durable. . The raw material of hot-dip galvanized angle steel is angle steel, so it is classified into the same angle steel.
2. The cold galvanizing process is used to protect the metal from corrosion. For this purpose, a coating of zinc filler is used, which is applied to the surface to be protected by any coating method, and after drying, a zinc filler coating is formed and dried. The layer has a content of zinc (up to 95%). It is suitable for repair work (that is, in the process of repair work, only in the damaged surface of the protected steel, as long as the surface is repaired, it can be recoated). The cold galvanizing process is used for the corrosion protection of various steel products and structures.
Cold-galvanized coatings are mainly anti-corrosion by electrochemical principle. Therefore, it is necessary to ensure sufficient contact between the zinc powder and the steel, and the electrode potential difference is generated, so the surface treatment of the steel is very important. Before spraying cold galvanizing, mechanical rust removal (blasting, shot blasting, etc.) should be selected to make the surface cleanliness of the steel reach ISO 85O1—1 Sa 2.5, equivalent to GB 8923 Sa 2.5. Its text is defined as: "After mechanical descaling of steel, the surface is free of oil, rust, no scale and other dirt, or only a slight trace; 95% of the steel surface is impacted by steel shot (sand), exposed The luster of the metal."
For another indicator of surface finish quality – roughness, different cold galvanized materials have different roughness requirements. In the construction specification of Zinga, the average roughness Ra is required to be 12.5, that is, the roughness Rz is 55 to 75 μm. In the "Strong Zinc" and "Robaru" construction instructions, the roughness requirements are slightly lower, Rz = 40 ~ 60 microns.
If cold galvanizing is formed into a film alone, the surface roughness can be controlled to be slightly smaller as an anticorrosive coating to ensure the thickness of the cold galvanized coating; and when cold galvanizing is used as the bottom layer of the heavy anticorrosive coating, the total matching coating When the thickness is greater than 180 microns, the surface roughness Rz of the steel should be greater than 60 microns in order to ensure the adhesion of the entire coating.
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