Corrosion protection is integral to structural longevity. At Omkar Gratings, we operate an advanced 7-tank hot-dip galvanizing plant in Mumbai engineered to provide superior metallurgical bonding, uniform zinc coating thickness, and cathodic protection across industrial steel gratings, cable support systems, and custom steel fabrications.
Engineered 7-Tank Pre-Treatment & Galvanizing Process
Achieving defect-free zinc protection requires rigorous multi-stage chemical cleaning. Our fully monitored 7-tank sequence removes surface impurities, oils, and mill scales, establishing an active steel surface ready for complete metallurgical diffusion in molten zinc.
Degreasing / Caustic Cleaning
Components are immersed in an alkaline hot degreasing bath to eliminate cutting oils, grease, lubricants, and shop soils without attacking the underlying base metal.
First Water Rinsing
Thorough high-flow water rinsing removes alkaline chemical carryover and caustic flakes, protecting the subsequent pickling tanks from contamination.
Acid Pickling
Controlled immersion in dilute hydrochloric acid baths dissolves stubborn mill scale, oxides, and rust, exposing pure metallic iron across the entire structural geometry.
Second Water Rinsing
A secondary continuous water rinse flushes residual acid solutions and dissolved iron salts, preventing premature sludge generation in the flux solution.
Pre-Fluxing Solution
Submersion in a heated aqueous zinc ammonium chloride solution prevents re-oxidation of cleaned steel before dipping and enhances metallurgical wet-out in molten zinc.
Hot-Dip Galvanizing Bath (435°C – 455°C)
Components are submerged in high-grade molten zinc maintained at 815°F–850°F (435°C–455°C). The reaction forms four distinct iron-zinc alloy layers (Gamma, Delta, Zeta, and Eta), creating an abrasion-resistant, cathodic barrier.
Quenching, Passivation & Finishing
Coated articles undergo controlled water quenching or dichromate chemical passivation to arrest alloy growth, prevent wet-storage stain (white rust), and finalize clean surface handling.
Global Technical Standards & Quality Compliance
Our hot-dip galvanizing line conforms to international engineering standards, meeting strict client specifications for minimum coating thickness, surface continuity, and zinc adhesion strength across all structural packages:
| Standard | Specification Scope | Minimum Coating Thickness |
|---|---|---|
| BS EN ISO 1461 | Hot dip galvanized coatings on fabricated iron and steel articles | 85 µm (typical for steel ≥ 6 mm thickness) |
| ASTM A123 / A123M | Zinc (Hot-Dip Galvanized) coatings on iron and steel products | Grade 100 (≈ 100 µm) / Grade 85 |
| IS 2629 / IS 4759 | Indian standards for general practice and coating requirements | Conforming to specified structural micron classes |
| BS 729 / BS 4592 | Historical reference for industrial flooring, walkways, and stair treads | Fully compliant protective alloy layers |
Technical Advantages of Industrial Galvanizing
Unlike conventional paint systems that merely provide a topical shield, hot-dip galvanizing forms a metallurgical alloy that physically integrates with the parent steel. Key engineering advantages include:
- Cathodic Self-Healing: Even if physical damage occurs to the coating, surrounding zinc acts as a sacrificial anode, preventing rust spread.
- Complete Internal & External Coverage: Liquid immersion protects recesses, hollow sections, welded intersections, and cut edges that spray coatings cannot reach.
- Abrasion & Impact Resistance: The hard metallurgical intermediate alloy layers provide superior resistance to handling abrasion during global transit and site erection.
- Extended Maintenance-Free Lifecycle: Up to 50+ years service life in normal rural environments and 25+ years in harsh industrial or marine atmospheres.