CONSTRUCTIONAL PART REPAIR METHOD Russian patent published in 1997 - IPC

FIELD: repair of metal constructions, such as bridge constructions, parts and units of lifting and road-building machines. SUBSTANCE: method involves drilling hole at the end part of crack; spreading and welding crack. Hole is drilled at distance from crack end equal to 0.4-0.5 of its diameter in direction tangential to radius of curvature of arced portion adjacent to crack end. Crack is spread at an angle of 50 deg ≅ α≅ 75 deg. Upon welding of crack, construction under repair is subjected to multiple (at least triple) loading cycle, with stress in part exceeding nominal value by 25%, and to single cycle loading to nominal value in part. Spreading of crack is effectuated at variable spread angle along its length. Method may be used to repair constructions made from metal rolled products and castings of thickness not exceeding 40 mm. EFFECT: increased efficiency, simplified method, improved quality of repaired parts and enhanced reliability in operation. 3 cl, 3 dwg