METHOD FOR MAKING SHEATHING PRESET-CONTOUR SHAPE Russian patent published in 2006 - IPC B21B17/14 

FIELD: manufacture of sheathing determined shape by cold reduction of hollow welded blank such as tube.

SUBSTANCE: method comprises steps of feeding and placing blank onto feed roller table; orienting and matching blank relative to rolling mill; deforming hollow welded blank between rolls of several successively arranged stands at simultaneously reducing blank along its perimeter and creating longitudinal tension drawing effort; finally working blank in multi-roll pass according to size of ready of product. Hollow welded blank is deformed while perimeter and thickness of its wall are hold constant during the whole manufacturing cycle beginning from guiding welded blank till discharge of ready product for several successive transitions. Strict order of said transitions is determined by creation of deformation zones at optimized stress-deformed state of metal and by deformation intensity between stands of rolling mill. Accuracy for keeping constant values of wall thickness and perimeter of initial welded tubular blank is controlled due to calibration of rolls in such a way that to act locally upon metal flowing in tube in critical points along perimeter. Reduction is realized due to preliminarily reducing tube along its contour for shaping ribs; further reducing blank for forming two basic surfaces of the most simple geometry and preliminarily forming two remaining basic complex-geometry surfaces. Then said two remained basic complex-geometry surfaces are finally reduced. Triangle bending portion is rolled and grooves are formed in vertical end strut and supporting platform. Triangle bending portion is additionally rolled and geometry parameters of shape that are important for operation are finally sized with possibility of compensation of errors of shape members with free dimensions. Then ready shape is straightened. Reduction is performed at similar angular velocity of rolls in all stands and slip is provided in zones of velocity error. Procedures of preliminary reduction of tube along its contour for forming ribs, further reduction of blank for forming two basic simple-geometry surfaces, preliminary forming of two remaining basic complex-geometry surfaces, further reduction for finally forming two complex-geometry basic surfaces, rolling triangle bending portion and forming grooves in vertical end strut and in supporting platform are performed in double-roll stands. Additional rolling of triangle bending portion, final calibration and straightening of ready shape are performed in multi-roll stands. Welded tubular blank is oriented in feed roller table in such a way that welded seam is in lower flange of shape that is parallel to supporting platform. The whole manufacturing process is realized in the same line. Invention provides possibility for acting upon stress-deformed state of metal in deformation zone for producing sheathing preset-contour shape from widely used in industry welded tube blank with diameter 114 mm and wall thickness 3 mm during optimized technological mode concerning metal state and deformation intensity.

EFFECT: enhanced accuracy of geometry size, lowered energy consumption for making shape.

5 cl, 5 dwg, 1 ex