METHOD FOR MAKING TUBES OF HARD-TO-FORM STEELS AND ALLOYS WITH INCREASED COEFFICIENT OF LINEAR EXPANSION Russian patent published in 2003 - IPC

FIELD: rolled tube production, namely processes for making tubes of hard-to-form steel kinds and alloys with increased coefficient of linear expansion. SUBSTANCE: method comprises steps of rolling hollow sleeves or billets heated until yielding temperature in pilger mill for rolling tubes with use of increased-conicity mandrels heated at rolling tuning tubes of carbonaceous steel kinds; heating working portion of mandrel until mean temperature equal to or exceeding desired temperature of leading end of tube at time moment of tube coming off mandrel while temperature drop along length of working portion of mandrel is no more than 100 C. EFFECT: elimination of mandrel jamming at rolling, reduced factor of metal consumption due to lowered lengthwise wall thickness difference, lowered loads of rolls and of drive system of pilger mill, prevention of damages of rolls and spindles. 2 cl, 1 tbl