METHOD OF INCREASING RESISTANCE OF STEEL PIPELINES AGAINST CORROSION BY ALUMINIZING Russian patent published in 2016 - IPC C23C10/22 C23C2/12 

FIELD: metallurgy.

SUBSTANCE: invention relates to methods of increasing resistance to corrosion and can be used in underground pipeline transport. Method of aluminising steel pipe includes cyclic heating of surface of steel pipe by pulses of electromagnetic radiation in aluminium melt above point Ac₃ with further cooling below point Ar₁ at heating and cooling rate of not less than 1 K/s, wherein heating is performed to temperature not exceeding 1,220 ± 10 K and cooling to temperature not below 820±10 K, and duration of holding at heating and cooling at extreme temperatures is determined by required depth of penetration of aluminium and its distribution uniformity in steel. Heating of surface of steel pipe is performed in protective atmosphere for depth of penetration of aluminium in steel, and specified cyclic heating in aluminium melt with further cooling is carried out not more than three times. To prevent oxidation molten aluminium is under a layer of molten cryolite. During aluminising, pressure in pipe is kept at 0.5-0.75 of working pressure generated during its operation.

EFFECT: higher efficiency and resistance of steel to high-temperature corrosion.

1 cl, 3 dwg