- Doha galvanizing is capable of providing quality Hot dip galvanized coatings on all kind of steel complying with all applicable national and international standards.
- Efficient logistics to handle high volumes of materials.
- Solution based approach by our staff exceeds customer expectation levels.
HOT DIP GALVANIZING
Hot Dip Galvanizing is the process of coating iron and steel articles with zinc for protection against corrosion by dipping the articles in molten zinc at a temperature of 450 ± 5° C.
Zinc metallurgically bonds with steel and thereby protects the underneath steel from corrosion.
The life of hot dip galvanized steel depends up on the environment to which it is exposed to, however, in a moderate industrialized environment, galvanized steel has a life of 20-25 years.
PROCEDURE
- Surface Cleaning by Abrasive blasting and acid pickling.
- Rinsing: Rinsing the steel in fresh water
- Fluxing: Immersing in zinc ammonium chloride solution.
- Drying: To remove moisture content and also pre heat the steel.
- Dipping: The steel materials are then dipped into molten zinc bath maintained at a temperature of 450 ± 5° C.
- Quenching: The galvanized materials are either air cooled or quenched in a water bath for cooling.
- Recovery and final inspection: Excess zinc on the material, lumps, spikes, etc. are removed by sanding, filing, etc.
- Coating thickness is measured with a calibrated magnetic thickness gauge (Elecometer). Materials are bundled and stacked in the yard for dispatched.
DESIGN
The quality of Galvanized products can be improved taking into consideration of the requirements to be followed for steel, at the design stage itself. Our Engineers are available to advise the steel designers/fabricators, based on applicable standards, the significant features for designing the steel members to be hot dip galvanized, which results in high quality products.
BATH SIZE 8 Mtr long x 1.6 Mtr wide x 2.5 Mtr depth
- Acid fume and zinc fume extraction system
- Natural gas heating systems.
- Automated temperature controls for zinc bath
- Integrated Management systems Certified Company
- Zinc used in Doha Galvanizing is Special High Grade 99.995% Pure (SHG Zinc)
APPLICABLE INTERNATIONAL STANDARDS
| STANDARDS | DESCRIPTION |
| BS EN ISO 1461 – (BRITISH STANDARD) | Hot dip galvanized coatings on fabricated iron and steel articles—Specifications and test methods |
| ASTM A 123/M (AMERICAN STANDARD) | Standard Specification for Zinc (Hot-Dip Galvanized) Coating on Iron and Steel Products |
| ASTM A153/A153M | Standard Specification for Zinc Coating (Hot-Dip) on Iron and steel Hardware |
| ASTM A385/A385M | Standard Practice for Providing High-Quality Zinc Coating(Hot-Dip) |
| ASTM A780/A780M | Standard Practice for Repair of Damaged and Uncoated Areas of Hot-Dip Galvanized Coatings |
| ASTM B 6 | Standard Specification for zinc |
STEEL ACCESSORIES, LIGHTING POLES, STEEL FRAME, STEEL GRATINGS, STEEL PIPE / TUBE, STRUCTURAL STEEL
