Actual Problems in Machine Building 2017 Vol. 4 No. 4

Актуальные проблемы в машиностроении . Том 4. № 4. 2017 Технологическое оборудование, оснастка и инструменты ____________________________________________________________________ 83 THE REASON AND PREVENTION OF BOUNCE SPINDLES WELDED SCREW-STEERING COLUMNS Tokarev A.O., D.Sc. (Engineering), Professor, e-mail: aot51@ngs.ru Mironenko I.G. , D.Sc. (Engineering), Professor, e-mail: mig60@ngs.ru Fedotova E.S. , Ph.D. student, e-mail: ekaterina-lin@mail.ru Siberian State University of Water Transport, 33 Schetinkina st., Novosibirsk, 630099, Russian Federation Abstract In this work the analysis of the reasons for frequent breakdowns hollow, assembled by welding shafts – ballers serving to rotate the nozzle propeller - steering ship "Balt Fleet". The baller consists of a middle part made of seamless pipe, laminated steel 35 (0,32 – 0,39% carbon). At the end of the hollow shaft are wear resistant slot bushings, welded butt joints. The ma- terial of bushing – alloy steel 42 Cr Mo (С - 0,38 – 0,45%; Si - 0,17 – 0,37%; Mn - 0,50 – 0,80%; Cr - 0,90 – 1,20%; Mo - 0,15 – 0,25%). It is established that the damage was due to faulty fusion of the weld with the base metal. A con- tributing factor to the propagation of cracks that caused the lack of penetration, it was the presence of hardening structures in the heat affected zone of the weld. Cracks occurred on the surfaces of the cutting of the weld extend in the direction of greatest mechanical stress along the boundaries of dendrite grains of the welding. Proposed measures to address faulty fusion, is the welding of the hollow shaft in a pre-heated condition and subsequent annealing. Keywords propeller – steering column (PSC), vertical shaft, crash, hairline fracture, weld seam, microstructure, heat-affected zone