Termal sürtünmeli delme işleminde oluşan kovan boyutları ve mikro sertlik değişimlerinin araştırılması
Gazi Üniversitesi Mühendislik-Mimarlık Fakültesi Dergisi
Highlights: Graphical/Tabular Abstract Tool diameter and material thickness has an important effect on friction drilling of brittle and ductile material The parameters affecting the bushing wall thickness and bushing height have been determined The microstructure and the change of micro-hardness in the bushing structure were investigated Figure A. Stages of conventional friction drilling process and the resulting bushing pictures Purpose: The purpose of friction drilling method (FDM) is
... increase the length of the connection for the bushing formed on the wall and the lower part of the hole in the thin-walled sheet. Theory and Methods: In the study, A7075-T651 Aluminum alloy and St37 steel plates supplied in 2 mm, 4 mm, 6 mm, 8 mm and 10 mm thicknesses and 70x500 mm dimensions were used. A total of 20 HSS and 8 WC friction drilling tools were used. The tests were carried out using HSS tool for A7075-T651 alloy with n=1120 (rpm) rotation speed, f =25 mm/min feed rate and tool taper angle θ=36°, 60 pieces using WC tool for St37 steel material. A total of 132 experiments were conducted by drilling holes. The experiments were carried out on a TYT400 type universal milling machine. The test specimens were rigidly fixed to the milling machine table with bolts and lugs using a clamping mold. In order to prevent the loss of time required for the workpiece temperature to cool down to room temperature, the holes were successively drilled at constant distances with equal spacing of 100 mm from each other. Results: Material thickness, tool diameter, shaft length of the drilling tool (l1) and the heat generated by the friction effect are the main factors affecting the bushing height in FDM. As the material thickness increases, the contact area between the rotating tool and the drilled material increases, so the flow of material in the direction of the tool increases along the shaft length (l1) of the tool. In ductile materials, a bushing can obtained that has a cylindrical length suitable for its purpose and increases the length of the connection. But it has been determined that a bushing in the desired shape cannot be obtained in brittle materials. Conclusion: It has been determined that tool diameter, material thickness, brittle material and ductile material have an important effect on bushing wall thickness and bushing height.