Comparative Study Concerning the Generation of some Circular Grooves by Radial Cold Rolling with Roller Tools and Cutting

Abstract

This study is part of the concerns that the authors have had in recent years, representing an extension of a research project funded consisting in modelling representative cold rolling processes of profiles. This paper presents a comparative analysis of quality of the superficial layer of a circular profile (grooves) obtained by two different processes: radial rolling with two roller tools and turning with radial feed. Also, the two processes are compared from the viewpoint of economic efficiency. The materials used for the experiments are frequently used to obtain pieces with circular grooves: two types of cementation steel and two types of heat treatable steel. The characteristics of the superficial layer which describe its quality and which are comparatively analyzed in connection to the two processes are: roughness, microstructure and micro-hardness. The economic efficiency of the two processes was assessed by means of the costs implied and the productivity of processing. The interpretation of the results obtained enabled stressing the advantages to generate circular grooves by cold radial rolling from the point of view of the quality of the superficial layer of pieces, as well as the limits of the use of this process from the viewpoint of economic efficiency.

Numerical investigation of the radial cold rolling process of the grooves

“…The dependence of the profile forming time (t d ) on the maximum set force (F m ) is obtained by inputting in the relation (8) the values of the coefficients a and A that are expressed by the relations (2) and (3):…”

“…Cold forming presents major advantages compared to the cutting processes [1][2][3][4][5][6] : (i) more productive, (ii) no production of chips, and (iii) high quality of the generated surface. Moreover, because the deformation occurs at ambient temperature, the initial properties of the material are irreversibly changed, forming a continuous fiber in the material of the part, which ensures better mechanical properties, [7][8][9] such as: roughness, micro-hardness, and fatigue resistance.…”