In all kinds of metal surface heat treatment, mechanica […]
In all kinds of metal surface heat treatment, mechanical processing, transportation and storage process, inevitably will be oxidized, create a layer thickness of oxide layer. At the same time, are also susceptible to various oil pollution and adsorption of some other impurities. Oil and some of the adsorbate, thin oxide layer can be successively solvent cleaning, chemical processing and mechanical processing, or directly with chemical treatment. For severe oxidation of the metal surface, the oxide layer thicker, can't direct solvent cleaning and chemical treatment, and the best mechanical processing first. Usually after processing, the metal surface with high activity, again more easily polluted by dust, moisture, etc. To this end, after processing of metal surface should be done as fast as possible to connect.
Defatted processing method . Commonly used solvents as trichloroethylene, acetone, ethyl acetate, butanone, etc.
Method  in the following solution after degreasing in 70-75 ° C under dipping 5 min: naoh 12 100 water rinse with cold water, then in the following solution at 20 ° C impregnating 5 min: chrome oxide 10 water 100 2.8 rinse with cold water, anhydrous sodium sulfate and washing with distilled water, at 40 ° C and dry.
Method  after degreasing in 6.3% sodium hydroxide solution at 70 ° C under immersion 10 min, after wash, and then in the following solution in 55 ° C dipping 5 min: chrome oxide 13.8 1.2 water calcium sulfate 85 washing with distilled water, and then in the following solution in 55 ° C impregnating 3 min: chrome oxide 10 sodium sulfate water 0.5 0.5 below 60 ° C dry after washing.
Method  in the following solution under 20 ° C impregnating 3 min: chrome oxide 16.6 glacial acetic acid sodium nitrate 20 105 100 water rinse with cold water, distilled water rinse and dry under 40 ° C.
Method  in the following solution in the 60-70 ° C impregnating 3 min: 10 magnesium sulfate sodium dichromate 80 5 manganese sulfate water rinse with cold water, distilled water rinse and drying under 70 ° C.
After degreasing method  magnesium alloy die casting in the following boiling solution impregnation 20 min: sodium dichromate ammonium sulfate 1.5 3 ammonia water (d = 0.88) 0.88 93.7 rinse with warm water, distilled water rinse and dry.
7 [method] under 30 ° C 10% solution of ammonium fluorine hydride ZhongYang polarization to current density is lower than 0.45 A/m2 (one electrode panel), ac voltage 90-120 - v, and then washed, dry.
Method  in 20 to 30 ° C the following solution ZhongYang polarization: potassium hydroxide aluminum 12 anhydrous potassium permanganate potassium fluoride sodium phosphate 3.4 3.4 0.75 1.5 water 80 ac voltage 85 v, current density of 1.1 1.4 A/m2, and then washed with cold distilled water, and dry.
Method  in 70 ° C the following lye bath after degreasing 5-15 min: naoh 23 400-34 water to wash in cold water for 5 min, 5-15 min in the following solution dipping, temperature 55 ° C: chrome oxide calcium nitrate 57-68 5 450 water to wash in cold water for 2 min, 3-12 in the following solution dipping min, temperature 55 ° C: chrome oxide 45 sodium phosphate 8 450 2 min to wash in cold water, water and dry under 40 ° C for 30 min.