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

FIELD: metallurgical production, namely manufacture of cone hollow elongated metallic articles by hot rolling of cylindrical tube-billets in tube rolling mills having pilger and automatic mills at lowering diameter and increasing wall thickness of billet from one end to other.

SUBSTANCE: method comprises steps of heating blanks till yielding temperature. Piercing them in skew rolling mills, rolling in plants having pilger mills and automatic mills, cutting by measure length pieces, rolling in reducing-stretching mills with three- and four-roll stands; after guiding cone elongated hollow article into roll pass of last stand of reducing-stretching mill, braking rolls of all stands of mill till arresting them for time period t; successively drawing together by value δ rolls of each stand except last one for time period t1 ; determining time period t1 according to formula t1 = t/(n-1) where t - time period for delivering blank of cone elongated hollow metallic article (due to reverse rotation of rolls) to inlet side, s; n - number of stands of reducing-stretching mill. Elongated hollow metallic articles at inlet side of reducing-stretching mill are fed to skid for cooling and then for transferring them to finish operations including straightening, removal of technological crop, inspection and reception of ready articles.

EFFECT: possibility for realizing industrial flow production of high-quality cone elongated hollow metallic articles with desired geometry parameters in tube rolling aggregates with pilger and automatic mills including reducing-stretching mills.

2 cl