Abstract
Results of experimental studies of the influence of wall thickness ratio and relative height of work-pieces (made of steel with 0.3% C), that vary in the ranges of 2…10 and 0.6…10 respectively, on the residual stresses and deforming forces of the single-cycle compression mandrelling of 5 mm di-ameter holes performed with allowances varied between 1.9 and 13.7% of the diameter are given. It is found that, due to lower resistance to deformation the metal forced out of the hole is moved to the external surface and outlet face of the workpiece when the height of workpiece is small. In this case, a depression is formed on the inlet face of the workpiece. It is revealed that the hoop residual strain on the external surface of the workpieces being mandrelled increases with the allowance in-creasing and ratio of wall thickness decreasing, and is almost independent of workpiece relative height. It is shown that workpieces with greater wall thickness ratio (in the range of wall thickness ratio mentioned above) undergo throughout plastic deformations with allowance increase. In this regard, it is noted that the current classification of mandrelled workpieces based on the wall thick-ness ratio is unreasonable.
Keywords: Hole mandrelling; Residual strains in workpieces; Deforming forces
3. Rozenberg A.M., Rozenberg O.A. Mehanika plasticheskogo deformirovanija v processah rezanija i deformirujushhego protjagivanija (Mechanics of plastic deformation in the process of cutting and deforming broaching). Kiev, Naukova dumka, 1990. 320 p.
