| 摘要 |
FIELD: rolled tube production, namely method for preparing forged and continuously cast billets, electroslag refining ingots, hollow sleeve-blanks of electroslag refining for rolling boiler tubes of given steel kinds. ^ SUBSTANCE: method is used also for preparing hollow sleeve-blanks of electroslag refining and hollow centrifugally cast billets of hard-to-form steels and alloys of given kinds for rolling commercial seamless hot rolled tubes in tube rolling plants with pilger and automatic mills and conversion tubes for further rerolling in cold rolling mills according to given standards. Method comprises steps of mechanically turning, fire or plasma trimming of forged or continuously cast billets, ingots of electroslag refining by stripping metal in the form of cuttings, scale or slag, turning and boring or plasma trimming hollow sleeve-blanks of electroslag refining and hollow centrifugally cast billets and then removing remained localized flaws by emery or fire trimming and removing metal in the form of cuttings, emery-metallic dust, scale, slag while heating blanks till yielding temperature. Surfaces of forged or continuously cast billets, electroslag refining ingots, outer and inner surfaces of hollow sleeve-blanks of electroslag refining, of centrifugally cast billets are remelted by means of non-consumable electrode in argon-shield atmosphere without waste metal occurring. Surfaces of hollow sleeve-blanks, centrifugally cast billets are remelted at formation of screw-like wavy surface in the form of sine with amplitude no more than 5 mm, screw pitch no more than 30 mm and inclination angle relative to axis in range 60 - 70°. ^ EFFECT: reduced metal consumption due to elimination of mechanical working of forged pieces and electroslag refining ingots, turning and boring of hollow sleeve-blanks and centrifugally cast billets, lowered number of flaws such as slivers, scabs on sleeves and tubes of hard-to-form steels and alloys, simplified process for preparing tubes for cold conversion, reduced cost of boiler, commercial and conversion tubes of high-cost steels and alloys. ^ 9 cl, 1 tbl |
