METHOD FOR PRODUCING ELONGATED CONE HOLLOW METALLIC ARTICLES BY ROLLING PROCESS Russian patent published in 2006 - IPC B21B21/00 

FIELD: manufacture of cone elongated hollow metallic articles by rolling them of cylindrical tube blanks in tube rolling aggregates with pilger mills and automatic mills at lowering diameter of tubes and increasing their thickness.

SUBSTANCE: method comprises steps of heating blanks up to plasticity temperature; piercing them in skew rolling mills; rolling in aggregates with pilger mills and automatic mills; cutting by measured length pieces and rolling in stretch-reducing mills. Cone elongated hollow metallic articles are rolled in stretch- reducing mills till time moment of outlet of leading end of cone elongated hollow metallic product from last stand of stretch reducing mill and then rolls of all stands are arrested/braked. Blank of cone elongated hollow metallic article is fed due to reversing rolls of stands to inlet side of stretch reducing mill and it is transferred to skid, cooled and fed to finishing and straightening. Then technological scrap is removed, article is subjected to inspection and ready products are received. Distance between axis of first stand of stretch reducing mill till axis of last stand of said mill is set equal to length of cone elongated hollow metallic article from which length of technological scrap of article base portion and length of technological scrap of article top portion are extracted. Sad distance is determined according to expression L = l/n where l -length of ready product, mm; l = l_pr -_{lst -lend , n - quantity of stands of stretch reducing mill; lpr - length of cone article after rolling it, mm; lst - length of technological scrap of article base portion,mm; lend - length of technological scrap of article top portion, mm. Number of stands of stretch reducing mill is selected according to preset conicity degree of elongated hollow metallic product and it is determined with use of expression n = l + (Dmax - Dmin)/δ where Dmax - diameter of base of cone elongated article (diameter of blank),mm; D min-diameter of apex of cone elongated article, mm; δ - mean reduction value by diameter in working stand of stretch reducing mill, mm; l - first stand of stretch reducing mill used for biting tubular blank at reduction degree δ = 0. Height of one side of skid exceeds that of its other side and it is determined according to expression: h = h1 + (D max - D min)/2, where h1 - height of skid side on which base of elongated hollow article is moved, mm. Stands of stretch reducing mill are mounted in housing with pitch (spacing between axes of stands) whose value is determined by means of expression m = l/n. Stands of stretch reducing mill include three or four rolls.}

EFFECT: possibility for realizing flow type industrial production of high quality cone elongated metallic products with predetermined geometry parameters.

7 cl