METHOD OF MANUFACTURE OF STEEL GLASS-LINED PIPES FOR PIPELINES Russian patent published in 2018 - IPC C03C27/02 F16L58/14 C23D5/04 

FIELD: technological processes.

SUBSTANCE: invention relates to the production of steel vitrified pipes. Steel pipes ends are cut at an angle of 90 degrees and deburred, chamfered at an angle of 30 degrees to the end of the pipe, leaving the end ring 1–2 mm wide. Shape of the pipes ends, bends and additional elements is made with beveled edges for the welded joint type C-17. Then one end of the pipe is introduced a flared sleeve with a length of 109–111 mm to a depth of 30–40 mm for internal protection of the welded seam and adjacent zones and fixed by welding. After the inner surface of the pipe is cleaned by shot blasting and then blown. Apply a glass coating and burn vitrified pipes in 5 stages in a through electrical 5-section furnace with a length of 15 m. Furnace contains four heating zones, each is 3 m long, and one stabilization zone. Number of rotations evolutions of the pipe when moving through the furnace is set depending on the diameter of the pipe in the range 0.10–0.25 rpm, and the speed of its movement is 0.15–0.26 m/min. Time of the tube in the furnace is 58–100 min. At the first stage, the temperature is kept below the melting point of glass within 680–710 °C. At a second step, the glass is heated to firing temperature of 810–830 °C. At the third stage, the glass placed in the tube is heated to temperature of 920–930 °C. At the fourth stage there is smooth cooling down to 860–900 °C, formation and solidification of the coating. At the fifth stage, the pipe moves to the stabilization section.

EFFECT: obtaining a solid monolithic coating, increasing its strength.

1 cl, 1 dwg, 1 ex