METHOD FOR STRENGTHENING STEEL PLATES Russian patent published in 2000 - IPC

FIELD: processes for surface plastic deforming of steel plates by shots. SUBSTANCE: method comprises steps of successively deforming steel plate by means of small- and large-grain shots; realizing initial stage of strengthening with use of large diameter (2mm-3mm) shots in order to provide predetermined intensity of plastic deformation in centers of impressions equal to allowable uniform deformation of strengthened material; subjecting plate to uniform plastic deformation by stretching it until residual deformation value equal to (0.5-1.0)% in order to release residual stresses; performing secondary stage of strengthening with use of small diameter shots with diameter equal to (1-1,5)mm until receiving in center of impressions intensity of stress equal to yielding strength of plate material subjected to initial strengthening. EFFECT: increased useful life of steel plates in conditions of applying variable loads to them due to provision of strengthened layer with optimal distribution of residual stresses. 2 cl, 1 tbl