TESTING 1-2-3
OF ALUMINUM-SILICON CAST ALLOYS
INVESTIGATING THE MACHINABILITY
A series of drilling tests highlights how microstructural differences can affect machinability and tool wear.
T 1
2 3
AN MCDP STAFF REPORT
he increased use of aluminum-silicon alloys, par- ticularly in the automotive and aerospace industries, has led to additional research into microstructural properties to better understand their eff ects on ma- chinability. T ese alloys can have radically diff erent machining characteristics as a result of microstruc- tural diff erences, which in turn generate variations in composition and/or in manufacture. A team of researchers investigated the impact of microstructure and tool material on the machinabil-
ADDING IT ALL UP
“Effects of Alloying Elements and Cutting Tool Materials on the Machin- ability of Aluminum-Silicon Cast Alloys” Guillermo Garza-Elizondo, Ehab Samuel, Agnes Samuel and Fawzy-Hosny Samuel, Université du Québec à Chicoutimi, Chicoutimi, Québec, Canada; Adel M.A. Mohamed, Qatar Univer- sity, Doha, Qatar; Saleh Alkahtani, Salman Bin Abdulaziz University, Al Kharj, Saudi Arabia.
Background—The machining characteristics of aluminum-silicon al- loys can vary radically because of microstructural differences, which in turn generate variations in composition and/or in manufacture. The research team examined differences in machinability and drill- ing force and the impact of tool material on tool wear and life.
Procedure—Test blocks of two 396 alloy variants and a B319.2 alloy were machined with four different drills. The four tools were used on the three alloys in fatigue testing, with the goal number of holes being 2,016. Results and Conclusions—The 396 alloys’ higher silicon content (10.8%) compared to the B319.2 alloy (7.5%) required greater cutting force and torque but did not affect tool life. The high precision solid carbide drill was best for the 396 alloys, requiring the lowest drilling force and torque, while the cobalt drill was best for the B319.2 alloy.
ity of aluminum-silicon alloys. T e results appear in the paper, “Eff ects of Alloying Elements and Cutting Tool Materials on the Machinability of Al-Si Cast Alloys,” by Guillermo Garza-Elizondo, Ehab Samuel, Agnes Samuel and Fawzy-Hosny Samuel, Université du Québec à Chicoutimi, Chicoutimi, Québec, Canada; Adel M.A. Mohamed, Qatar University, Doha, Qatar; and Saleh Alkahtani, Salman Bin Abdulaziz University, Al Kharj, Saudi Arabia. Drilling is one of the most common
machining processes in the automotive and aerospace industries. In response to market pressures, drilling cycle times must be decreased with met- alcasters still meeting tight tolerances. Aluminum-silicon alloys, which have a relatively high abrasive action, are machined primarily using solid carbide drills. T e research team designed a series of tests using four diff erent drills on three alloys to examine the eff ects of ferrous intermetallics and free- cutting elements on the machinability, drilling force and torque, and how tool material aff ected tool wear and life.
Question What eff ects do microstructural
changes in aluminum-silicon alloys and drilling tool material have on overall machinability?
Sept/Oct 2013 | METAL CASTING DESIGN & PURCHASING | 39
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