METHOD OF ELECTROLYTIC CHROMIUM PLATING OF THE INNER SURFACES OF THE PIPES AND THE INSTALLATION FOR THE METHOD REALIZATION Russian patent published in 2006 - IPC C25D7/04 C25D19/00 

FIELD: non-ferrous metallurgy; methods of the electrolytic chromium plating of the inner surface of the pipes.

SUBSTANCE: the invention is pertaining to the field of the electrolytic deposition of the metallic coatings in the flow of the electrolyte and may be used mainly for the chromium-plating of the long-length pipes with the ratio of their length to the pipes internal diameter exceeding 50 and the coating thickness of more than 200 microns. The method provides for the treatment in two stages and the deposition of the coating depth of 0.45-0,55 microns from the preset value is conducted in the mode of the pulsed current with duration of each pulse of 5.0-6.5 ms and the intervals between the pulses of 0.3-1.7 ms. Then the current is interrupted for 0.5-5.0 minutes and continue the deposition with the smooth increasing the current density at the rate of 4-6 A/s till the moment of an abrupt change in the cathode voltage. After that the current value is raised up to the operational value. At that the process is conducted at the preset values of the electrolyte flow and the resistance of the anode. The installation contains the tanks for technological solutions, the pumps, the pipelines system with the adjustable gates, the pressure and drain manifolds with gripping devices used for fastening between them of the treated pipes with the mounted inside them anodes and the current feed bars. At that the installation is supplied with the conveyer transportation equipment for relocation of the pipes from one of the process operation to another in the horizontal plane and the lifting gears with the fixers mounted under the carrying branch of the conveyer. The technical result: the invention ensures the high physical-mechanical characteristics of the coatings and their uniform depth at the increased productivity of the installation.

EFFECT: the invention ensures the high physical-mechanical characteristics of the coatings and their uniform depth at the increased productivity of the installation.

6 cl, 1 tbl, 1 ex, 3 dwg