METHOD OF PRODUCTION OF EXTRA-THIN TUBES FROM ZIRCONIUM ALLOYS AND DEVICE FOR ANNEALING THEM Russian patent published in 2006 - IPC C22F1/18 C21D9/00 F27B1/10 

FIELD: metallurgy; methods of production of extra-thin tubes from zirconium alloys and vacuum annealing plants.

SUBSTANCE: proposed method includes hot deformation of billets, preliminary cold deformation of billets at vacuum annealing, cold rolling of tubes at deformation at last stage at degree of 32-69% followed by final vacuum annealing performed in vertical position at temperature of alpha-region of zirconium continued for 2-3 h. At annealing, tubes are heated at rate not exceeding 55°C/min; their cooling is performed at rate not exceeding 30°C/min. Annealing device has housing hermetically closed with cover and provided with electric heaters, muffle with loading unit having seats for tubes and retainer for securing them in required position, suspension and system for evacuation of muffle and housing cavities. Loading unit is made in form of identical disks secured on central rod in tiers; disks have holes for forming the seat for vertical position of tubes; upper end of rod is articulated with suspension mounted in upper part of muffle.

EFFECT: reduction of maximum deviation of external diameter from rectilinearity of tubes.

5 cl, 3 dwg, 1 tbl