PROCEDURE FOR DIRECT-ON COATING INTERNAL SURFACE OF STEEL PIPE Russian patent published in 2011 - IPC C23D5/02 

FIELD: metallurgy.

SUBSTANCE: procedure consists in pipe rough induction burning at rate of transfer in inductor 0.17-2 m/min at temperature 600-750°C, in shot blasting internal surface of steel pipe and obtaining profile with projections and recesses not less, than 20 mcm at process rate 1-2 m/min, in successive dedusting with either compressed air or by vacuumising internal surface, or by washing with water and in drying with air at temperature not less, than 95°C, Further the procedure consists in quality control of surface, in application of slip coating by internal filling with control over rate of slip flow at 0.065-0.1 m/sec and at covering power 9.0-11.5 g/dm², density 1.79-1.82 kg/dm², temperature 18-20°C, in drying during 15-58 min at temperature 100-120°C and rate 0.17-0.67 m/min, in induction burning during 15-30 min at temperature 800-930°C and rate 0.33-0.67 m/min and in cooling. Also, application of slip coating, drying, inductive burning and cooling are performed at vertical position of the pipe.

EFFECT: industrial direct-on induction application of coating on internal surface of steel pipes at maintaining required quality and thickness of silicate-enamel coating with high efficiency.

4 cl, 1 dwg, 3 tbl