Burnishing is used increasingly as a finishing operation which gives
additional advantages such as increased hardness, fatigue strength,
wear resistance. It is well known that burnished surface characteristic
can significantly affect the resistance of components to failure when
subjected to high cycle fatigue loads. The fatigue crack, in general,
nucleates at the surface of the part, and then propagates into the-bulk.
Consequently, it is the state of the surface characteristic, where the
crack nucleates, that is of paramount importance.
Experimental work was carried out on a lathe to establish the effect of
four roller burnishing tool parameters; namely, burnishing speed,
burnishing depth, burnishing time and the initial hardness of material
on the surface microhardness, the out-of-roundness and the reduction
in workpiece diameter.
It was found that all input parameters have a controlling effect, with
different percentage, on the three output responses. The results
showed that burnishing depth and burnishing time are the most
important parameters controlling the values of both out-of-roundness
and reduction in workpiece diameter. Also, an increase in burnishing
speed leads to a considerable reduction in the microhardness index.
Out-of-roundness increases with a decrease in the initial hardness of
workpiece material