Effects of machining parameters upon the development of the white layer in hard turning of bearing steels (DIN 100 Cr6). / Efeitos dos parâmetros de usinagem na formação da camada branca em torneamento duro nos aços-rolamento (DIN 100 Cr6).

AUTOR(ES)
DATA DE PUBLICAÇÃO

2007

RESUMO

This work deals with the microstructural changes in the surface of steels machined by hard turning. A non-acceptable microstructure, called White Layer - WL, is usually found in the hard turned surface. The presence of the white layer depends on hard turning parameters, especially on the wear of the machining tool and cutting speed. The formation of the white layer was investigated in the present work by hard turning the inferior face of a roller-bearing ring fabricated with DIN 100Cr6 steel quenched and tempered (60 HRC hardness). The depth of the WL was measured by standard metallographic procedures. The mechanical properties (stiffness modulus, E, and Vickers hardness) of the surface layer were measured by intrumented indentation in three samples: one with no WL, and two containing a WL of respectively 7 and 12 mm. According to the literature the depth of the WL increases with the wear of the machining tool. This increased with cutting speed, but reaches saturation. The presentresults confirm an effect of tool advance upon the depth of the WL, such that decreasing the advance leads to an increase in its depth, but an effect of tool wear could not be recognized. The formation of the WL is discussed in the context of its effect on surface roughness.

ASSUNTO(S)

machining surface finishing usinagem response parameters acabamento de superfícies parâmetros de respostas

ACESSO AO ARTIGO

Documentos Relacionados