Kazuhiko Asano

Effect of heat treatment on free-machining properties of 2011 aluminum alloy:Investigation on machinability of aluminum alloys (2nd report)

Turning tests of 2011 aluminum alloys, subjected to T3, T4, T6 and T8 treatments, were carried out and the free-machining properties were compared. The free-cutting characteristics could successfully be evaluated by a new method proposed by the present authors. In this new method, the number of chips out of a constant amount of machined materials is represented as a function of the cutting conditions. When T3-, T4- and T8-treated alloys were cut at high cutting velocities, by using tools with high side rake angles, chips of continuous stringy type were formed under a certain range of feed while discrete chips were formed under the other conditions. T6 treatment led to the formation of fine discrete chips under all conditions used. The good machinability was found to be produced by the heat treatment in order of T6>T8>T3>T4. However, the difference among the effects of T8-, T3- and T4-treatment on the machinability was negligibly small. The free-machining properties were independent of the kind and the distribution of aging products.