METHOD OF CHEMICOTHERMAL TREATMENT OF PARTS FROM PLAIN ELECTRICAL SHEET STEEL AND FURNACE FOR ITS IMPLEMENTATION Russian patent published in 1996 - IPC

FIELD: metallurgy. SUBSTANCE: invention deals with surface hardening of parts working, for example, as magnetic circuits. Part is heated in working chambers of electric furnace. Air is evacuated from working chambers up to 1-10 Pa in advance. Part is refined with hydrogen when heated to 900-950 C for the course of 1-1.5 h by cyclic feed of hydrogen atmosphere. Then calorizing by short-term action of folatile composition of aluminium is conducted. Holding is carried out by several cycles, each including vacuum treatment and feed of ammonia. Cooling of part is performed in electric furnace to 500-550 C with rate of 15 deg/min followed by further intensive cooling in hydrogen atmosphere to 100-150 C. Subsequent forced cooling is conducted in air. Electric furnace has two working chambers with independent systems of their heating and vacuum treatment, means for generation of magnetic field directed along axis of working chambers. One of working chambers has device for generation of lateral magnetic field. Devices for cooling of internal space are positioned inside working chambers. Parts loading/unloading mechanisms include fans. Loading carriages carry face covers of working chambers. Vacuum treatment systems includes ammonia dissociation gears. EFFECT: enhanced efficiency of electrochemical treatment. 2 cl, 3 dwg