Friction Drilling of Difficult-to-Machine Materials: Workpiece Microstructural Alterations and Tool Wear

Shayan Dehghan,B T Hang Tuah B Baharudin,Mohd Khairol Anuar B Mohd Ariffin,Mohd Idris Shah B Ismail

doi:10.3390/met9090945

Abstract

Difficult-to-machine materials are metals that have great toughness, high work-hardening, and low thermal conductivity. Friction drilling of difficult-to-machine materials is a technically challenging task due to the difficulty of friction drilling, leading to excessive tool wear, which adversely affects surface integrity and product performance. In the present study, the microstructural changes of workpieces and tool wear for friction drilling of AISI304, Ti-6Al-4V, and Inconel718 are characterized. It helps to have an in-depth understanding of heat generation mechanics by friction and the mechanism of the friction drilling process. The study contributes to providing an enhanced microstructural characterization of workpiece and tool conditions, which identifies the material behavior and shows how it affects the bushing formation quality and drilling tool performance. The results reveal that the abrasive wear is mostly observed in the conical region of the tool, which has maximum contact with hole-wall. Moreover, the low thermal conductivity of Ti-6Al-4V increases frictional heat generation severely, and reduces product quality and tool life subsequently.

Highlights

The fact that the hole-making process is one of the most important operations in industry is undeniable
The findings findings of of this this study study are the mechanism mechanism of friction drilling for difficult-to-machine materials that have high resistance to corrosion and wear
The microstructural analyses of workpieces and the drilling tool are studied in the following

Summary

Introduction

The fact that the hole-making process is one of the most important operations in industry is undeniable. As a green, non-traditional, hot-shear machining technology, established by Streppel and Kals [1], is a clean and chipless hole-making process with no cutting fluids that can fulfill the needs of dry machining [2]. It has not received any significant attention until last decade, when Miller [3] pioneered the use of this methodology for sheet metal hole-making. Several researchers successfully applied friction drilling in this direction and showed this process is an excellent alternative for hole stamping and nut welding [5], such as for screw coupling [6] and joining of dissimilar materials [7]

Methods

Results

Conclusion