METHOD OF REDUCTION HEAT TREATMENT OF ARTICLES MADE FROM HEAT-RESISTANT CHROMIUM-NICKEL STEELS Russian patent published in 2003 - IPC

FIELD: metallurgy; reduction heat treatment of changeable articles of metallurgical furnace equipment, mainly used furnace rollers, radiation and flame tubes made from heat-resistant steels. SUBSTANCE: proposed method includes austenitization at heating to temperature of 1000-1200 C at rate of 15-30 C per hour, holding at heat for 5-40 hours and slow cooling under furnace hood to 300-400 C at rate of 20-50 C per hour; above operations are carried out in atmosphere of high-purified and dehumidified hydrogen at dew point not above minus 50 C followed by further cooling in non-oxidizing atmosphere and holding at temperature of 300-400 C; then, cooling is air is accomplished. Proposed method ensures restoration of physico-mechanical properties of changeable parts of metallurgical equipment due to avoidance of surface and internal defects of structure together with thorough refining by carbon, nitrogen and sulfur. EFFECT: enhanced efficiency. 2 cl, 5 dwg, 3 tbl