Machining of titanium alloys with ultra-hard cutting tool materials

Pretorius, Cornelius Johannes (2013). Machining of titanium alloys with ultra-hard cutting tool materials. University of Birmingham. Ph.D.

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Abstract

This research explores the relative merits of existing and novel ultra-hard tool materials for finish turning titanium alloys. Phase 1 of the experimental work comprised evaluating the machinability of Ti-6Al-2Sn-4Zr-6Mo when employing carbide tooling with respect to tool life, wear behaviour, workpiece surface integrity and cutting forces. The machinability of Ti-6Al-2Sn-4Zr-6Mo using PCBN tooling was evaluated in Phase 2 experiments. It was shown that even with the use of high pressure jet cooling, carbide and low content PCBN grade inserts were unsuitable for high-speed (~200 m/min) finish turning of titanium alloys. Phase 3 research evaluated the machinability of Ti-6Al-2Sn-4Zr-6Mo and Ti-6Al-4V when employing PCD tooling with respect to tool life, wear behaviour, workpiece surface integrity and cutting forces. Benchmark tests producing response surface models were developed using conventional low pressure fluid supply and were found to be suitable for the prediction of tool life, surface roughness and cutting force within the range of parameters studied. The PCD inserts significantly outperformed both carbide (by a factor > 24) and PCBN (by a factor > 12) tools in high-speed finish turning, although the performance varied depending on the PCD structure, edge geometry, period of engagement, undeformed chip thickness and jet fluid parameters.

Type of Work:

Thesis (Doctorates > Ph.D.)

Award Type:

Doctorates > Ph.D.

Supervisor(s):