How do you test phosphating quality?

For this type of phosphating, its main purpose is to corrosion protection, corrosion resistance is the most important indicators. General quality inspection indicators include copper sulfate drip to more than 1min, salt water is greater than 2h, salt spray test is greater than 1.5h.

How do you calculate coating weight?

The density of the coating is sometimes stated as WPG or weight per gallon. If the vendor gives you the specific gravity of the coating (SG) multiply it by 8.33 to convert SG to density (lbs/gal). Therefore, you can now easily calculate the weight solids in a one gallon can of the coating.

How do you phosphate coating?

A phosphate coating is usually obtained by applying to the steel part a dilute solution of phosphoric acid, possibly with soluble iron, zinc, and/or manganese salts. The solution may be applied by sponging, spraying, or immersion.

Does phosphate coating add thickness?

These adhesive coatings provide an excellent base for painting. Coating thickness for zinc phosphate is between . 0002 and . 0006 inches and manganese phosphate coatings are typically between .

How is coating calculated?

For example, if a coating were 45% solids by volume, its theoretical coverage would be 1604 X 0.45 or 722 square feet at 1 mil dry film thickness. If a specification called for a dry film thickness of 2 mils, the theoretical coverage would then be 722 square feet divided by 2 mils, or 361 square feet per gallon.

What is the formula of galvanization?

Chromate coatings on galvanized steel are usually yellow and consist of a mixture of trivalent and hexavalent chrome solution. The chemical reaction of the chromate to the galvanized steel is shown below: Reduction of hexavalent chromium to trivalent chromium 3Zn + 2Cr+6 ——> 3Zn+ 2Cr+3.

What is the purpose of phosphate coating?

Phosphate Coating Process The process of Phosphate coating is employed for the purpose of pretreatment prior to coating or painting, increasing corrosion protection and improving friction properties of sliding components.

How do you measure phosphate coating thickness?

If the film density and composition does not change, it is possible to determine the thickness of the phosphate coating by measuring the intensity of the emission of the P Kα XRF line.

How is GSM coating calculated?

– Weight all test swatches accurately and calculate average weight of swatches. – Multiply the average weight of swatches by 100 to calculate GSM of the sample fabric. (Normally, the area of round GSM cutter is 1/100 square meters.)

What is galvanization give an example?

Galvanization or galvanizing is the process of applying a protective zinc coating to steel or iron, to prevent rusting. Ex: Iron Bridge can be protected from rusting by galvanizing the iron using zinc.

What should the weight of a phosphate coating be?

(Heavy Weight) processes giving coatings that consist essentially of manganese and/or iron phosphate, and have a weight not less than 7.5 g/ sq meter of treated surface. This class is normally used where maximum protection is desired particularly under oil, or grease, or where resistance to wear is required.

When to use phosphating after corrosion resistance test?

For oil or wax after the corrosion resistance test, it is best to use salt spray test, the specific should meet the salt spray time, both agreed by the supply and demand. Phosphating from the role of lubrication is mainly used in cold processing, generally zinc.

What are the main quality indicators for phosphating?

Phosphate after the workpiece, according to its use, its quality indicators for sub-inspection. The main quality control indicators, including the appearance of phosphating film, phosphate film thickness or film weight, phosphate film or post-treatment of the three common indicators of corrosion resistance.

What should the salt spray test be for phosphating?