The process standard, not the coating standard. Here is what IS 2629 actually governs, what it leaves to IS 4759, and how each stage runs on our own line.
IS 2629 is a recommended practice for the galvanizing process itself — the sequence of degreasing, pickling, rinsing, fluxing, drying, dipping and quenching, plus design guidance on how components should be made so they can be galvanized properly.
It is often quoted in a purchase specification as though it set the coating thickness. It does not. The coating mass requirement lives in IS 4759, uniformity testing in IS 2633, and coating-mass determination in IS 6745. A specification that says "galvanized to IS 2629" and nothing else has not actually specified a coating — ask for the IS 4759 grade as well.
The stages a component passes through, in order.
Galvanizing is on our own floor at Jangalpur, Howrah — not sub-contracted.
| Stage | How it runs here |
|---|---|
| Kettle | 7.0 m × 1.2 m × 1.6 m (L × W × D), operating at 450–460 °C |
| Surface preparation | Degrease, acid pickle, rinse, pre-flux and dry, in sequence, before every dip |
| Coating measured | 75–85 microns as standard, read on a calibrated dry film thickness gauge |
| Coating standard applied | IS 4759 for coating mass; ASTM A123 where an export specification calls for it |
| Uniformity | IS 2633 copper sulphate dip test |
| Coating mass | IS 6745 stripping method where the buyer asks for mass rather than thickness |
| Certification | Galvanizing inspection report issued with coating thickness readings per batch |
Longer members are handled by double-end dipping where the geometry allows it. Where a component will not fit or cannot be vented, we say so at quotation rather than after the dip.
Four different documents, four different jobs.
| Standard | What it actually specifies |
|---|---|
| IS 2629 | The galvanizing process and design for galvanizing. No coating mass. |
| IS 4759 | The coating mass required on structural steel, in g/m², by section thickness. |
| IS 2633 | The uniformity test — copper sulphate (Preece) dip. |
| IS 6745 | The method for determining coating mass by stripping. |
| ASTM A123 | The American equivalent of IS 4759, expressed as coating grades in microns. |
Answered from our own line, not from the standard's cover page.
No. IS 2629 is a recommended practice for the process. The coating mass requirement is in IS 4759, which for steel over 5 mm calls for a minimum 610 g/m². If a purchase order says only “galvanized to IS 2629”, the coating has not been specified — we ask for the IS 4759 grade before quoting.
75–85 microns as standard, verified with a calibrated DFT gauge and reported per batch. Where a specification is written in coating mass — the 610 g/m² that appears in most state utility purchase specifications — we galvanize to the equivalent thickness and certify the mass rather than the reading.
Yes. We accept job-work galvanizing from fabricators, OEMs and project contractors across Kolkata, Howrah and eastern India. Send the drawing or the component dimensions and we will confirm whether it fits the kettle and how it should be vented.
The kettle is 7.0 m × 1.2 m × 1.6 m. Longer members can be double-end dipped where the geometry allows. Maximum single-piece fabrication weight on our line is 5 tonnes.
Almost always surface preparation, not the kettle. Oil, paint, weld slag or a marking crayon that survives the degrease will resist the pickle, and zinc cannot react with steel it never touches. Enclosed volumes that trap flux or air are the second cause — which is why IS 2629 devotes space to design for galvanizing.
Yes. Every batch is issued with a galvanizing inspection report carrying the coating thickness readings. Third-party inspection by SGS, Bureau Veritas, TÜV, DNV or a customer-nominated agency is supported at the buyer's cost.
Tell us the standard, the coating requirement and the component, and we will confirm in writing what we can hold and how we will certify it. Galvanizing is on our own floor, so the answer comes from us and not from a sub-contractor.
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