METHOD OF THERMOCHEMICAL TREATMENT OF INTERNAL SURFACE OF PIPES Russian patent published in 1999 - IPC

FIELD: thermochemical treatment. SUBSTANCE: method includes continuous induction heating of rotating pipe, continuous supply of carbonizing gas to internal part of pipe in direction from rear end of pipe to front end in direction of its motion and heat treatment, and subsequent variations of supply of carbonizing gas to pipe inside at pipe coming out of zone of heating which is carried out in direction from front end of pipe to its rear end in direction of its motion. EFFECT: higher efficiency. 2 dwg, 1 tbl