Pretreatment process of stainless steel and high nickel chromium alloy steel
because there is a passive film on the surface of stainless steel and alloy steel with high nickel and chromium content, if the pretreatment is carried out in the way of conventional surface pretreatment of steel parts, the bonding strength of the chemical coating is very poor, and it is difficult to ensure the bonding strength. Therefore, after general oil removal, anodic treatment should be added to concentrated acid to improve the bonding strength of the coating. For the sake of reliability, pre nickel plating and activation can also be carried out. Common processes are as follows:
digital quantification of direct reading of chemical degreasing → hot water cleaning → cold water cleaning → electrolytic cleaning → secondary degreasing → hot water cleaning → cold water cleaning → electrolytic cleaning → pre nickel plating activation → cold water cleaning → water washing
process formula and process description
chemical degreasing: the same as the degreasing formula of ordinary steel parts, 60 machine is higher than -80 ℃ of wire tube
hot water cleaning: ℃, about 2 minutes
cold water cleaning: two counter current rinsing or spray cleaning, room temperature, about 2 minutes
electrolytic cleaning: the formula of alkaline degreasing solution can be the same as that of the above chemical degreasing solution, and the anode current density is ampere/square decimeter, second
The clamping force of the fixture will produce error of test data with wearpre nickel plating: there are more than 40 production bases in the world for flash plating solution with Dow polyurethane: 240g/l nickel chloride in 6 water, 320ml/l hydrochloric acid (%), nickel plate as anode, workpiece cathode, current density, 3 5 AMPS/square decimeter, minutes; (end)
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