GAGE FOR CALIBRATING WORKING TOOL FOR COLD ROLLING OT TUBES Russian patent published in 2007 - IPC B21B21/02 

FIELD: manufacture of rolled products, namely gages for calibrating working tool for tube cold rolling.

SUBSTANCE: in calibrating gage for working tool development of profile of outer working tool and profile of inner working tool are in the form of curves having portions for reducing, crimping and calibrating. Curves of profiles of crimping portions of outer and inner working tools depend upon factor Q of tube working. Said factor changes according to law of monotonic descending function and it is equal to relation of logarithmic reduction value of tube wall to logarithmic reduction value of tube mean diameter. Range of Q factor change is set according to yielding resource of rolled material. Factor Q = Q _init x e^{-q * x/l} where q = ln Q _init/Q _fin - boundary factor; l - length of crimping portion of outer and inner working tools; x - current length of portion of outer and inner working tools in designed range; Q_init , Q_fin - boundaries of range of changing of Q factor. Curves of profiles are determined by means of next equation D_{mean i-1} / D_{mean i}= (t_i-1 /t _i)^1/Q _i where D_{mean i} - mean diameter of tube in i-section equal to sum of diameter of inner working tool and tube wall thickness or to difference of diameter of outer working tool and tube wall thickness; t_i - thickness of tube wall for i-section; Q_i -factor of tube working for i-section.

EFFECT: improved quality of rolled tubes due to uniform distribution of residual stresses along tube length.

3 cl, 1 dwg, 2 tbl, 2 ex