PROTECTION OF METALS AGAINST CORROSION Russian patent published in 2014 - IPC C23C10/40 

FIELD: process engineering.

SUBSTANCE: invention relates to machine building and can be used for increase in antirust protection of metal pipes. Article is subjected to vacuum-diffusion chromium-plating. Note here that, first, abrasive-jet machining of inner and outer pipe surface is performed. Then, powder of ferrochromium with grain size of 0.1-50 mm is filled in the pipe. Pipe inner surface is evacuated and placed at drive mechanism arranged under stationary gas-flame burner, device for shot-blasting of outer surface and inductor. Then, pipe local zone is heated to 900°C to 1500°C. Note here pipe is continuously spun along its axis. At a time, gas flame burner arranged ahead of inductor is used to evaporate the ferrochromium powder on pipe surface. Shot-blasting device is located between burner and inductor. In 1 to 20 hours, 2 to 10 cycles of pipe reciprocation relative to inductor are executed. Thereafter, pipe is quickly depressurized and cooled down to remove said ferrochromium powder.

EFFECT: decreased rate of corrosion.

5 cl