The five kinds of fasteners phosphating defect elimination method

Fasteners to present all requirements in terms of cleaning after phosphating, so how to wipe out in detail, what are the cleaning method? Together and see it!

1. The phosphating film is not generated

Fastener parts are work hardening layer surface, sulfate content in solution, phosphating solution mixed with impurities, low content of phosphorus pentoxide, with strong acid corrosion appearance, make it show metal grain, treated with barium carbonate sulfuric acid root, should replace the phosphating solution, make up for phosphate.

The five kinds of fasteners phosphating defect elimination method

2. The phosphating film has a blank

The lack of nitrate, phosphorus pentoxide content is too low, the temperature is too low, sulfuric acid pickling bath ferrous salt increased, increase the zinc nitrate, increase the phosphate, temperature rise in solution, should replace the sulfuric acid solution.

3. The phosphating parts have a yellowish-white

Sediment, rust riveting, composite solution of sediment, the lack of nitrate, phosphate solution without washing net, scraping sediment trough, make up the zinc nitrate, except the phosphating film phosphating again in acid solution.

4. The phosphating film corrosion resistance to decline

And raw yellow rust phosphating film crystallization bulky or carefully, phosphating parts are salt residue, metal surface corrosion, high free acidity, phosphate shortage, adjust the free acidity and the ratio of total acidity, strengthen before phosphating of neutralization and water washing, phosphating iterations, make up for the zinc nitrate and nitrate.

The five kinds of fasteners phosphating defect elimination method

5. Phosphating film is too thin, crystal carefully

Phosphating time no high low, ferrous content, total acidity, parts are hardening layer surface, the temperature is too low, to extend phosphating time offset dihydrogen phosphate, iron, add water dilute solution or add phosphate to the ratio of acid, with strong acid corrosion appearance, raise the temperature, the phosphating film red corrosion resistance to drop, acid pickling solution in the attached to the appearance, iron slag of copper ions into the phosphating solution, replace the pickling solution, notice need not copper hanging fixture, phosphating film crystallization bulky, ferrous ion content is too much, parts appearance with remnants of salt, the lack of nitrate content in the solution, higher nitrate content in the solution, parts surface corrosion, iron reduction with hydrogen peroxide solution, the higher the temperature, strengthening neutralize or washed, increase the zinc nitrate, deal with nitrate with barium carbonate, the manipulation of the acid concentration and time, uneven phosphating film, hair flower oil removal is not net, phosphating temperature is too low, the appearance passivation state, different parts for heat treatment processing method, strengthen the oil removal, adjust the temperature, strengthen the pickling, adjust the concentration of the acid that exposed metal grain appearance.