Purchase specifications are written in coating mass. Inspection gauges read thickness. This converts between them and tells you which standards the figure actually satisfies.
Zinc runs 7.14 grams per square metre for every micron of coating. Divide a mass figure by 7.14 to get thickness; multiply a thickness by 7.14 to get mass. That single number reconciles an Indian purchase specification with a European one and with the gauge in an inspector's hand.
The most common case: 610 g/m², the figure in most state utility specifications, is about 85 microns. Set the calculator to 610 and a 10 mm section and you will see it meets IS 4759 and EN ISO 1461 but falls short of ASTM A123's Grade 100.
Enter a coating figure in either unit. Zinc runs 7.14 g/m² per micron, so the two convert exactly. Pick a steel thickness and the table shows what the three standards require against it.
| Standard | Requires | Your figure |
|---|
ASTM A123 rows use the structural shapes column. Coating grades for plate, strip, bar, pipe, wire and reinforcing bar differ — see the ASTM A123 page.
Our published standard range is 75–85 microns, read on a calibrated DFT gauge and reported per batch. Where a specification calls for 610 g/m² we galvanize and certify at or above the equivalent 85 microns, confirmed in writing at quotation against the section thicknesses in your drawing. A 100 micron ASTM A123 Grade 100 requirement is a heavier coating and is quoted as such.
Answered from our own line, not from the standard's cover page.
Divide by 7.14. Zinc has a density of about 7.14 grams per square metre per micron of coating, so 610 g/m² is roughly 85 microns and 460 g/m² is roughly 64.
Effectively yes — 610 divided by 7.14 is 85.4. The figures are used interchangeably in practice, which is why both appear on our inspection reports.
It simply sets a higher bar for structural shapes: Grade 100 means a 100 micron minimum average above a quarter inch, against IS 4759's 610 g/m² which works out at about 85. That is roughly 18% more zinc and it should be priced, not absorbed.
It is the minimum any single reference area may show, as distinct from the mean across the article. A coating can meet the 85 micron mean and still fail the 70 micron local on a corner.
Our standard range is 75–85 microns and we certify the readings per batch. A 610 g/m² or 85 micron mean requirement is met at or above the top of that range; a 100 micron ASTM Grade 100 requirement is quoted as the heavier coating it is.
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.
Request a quotation Galvanizing job work