Quote:
Originally Posted by DELurker
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from matweb.com...
1018 steel versus 6061-T6 aluminum versus ASTM A526 galvanized steel
I could never bring myself to use aluminum for a shaft. It is too weak (comparably) to take that shock and torsion loads, as well as being more prone to unannounced catastrophic failure over steel (steel bends and then breaks ... aluminum has a much smaller deformation period before it snaps under the same loads). I'd rather use a steel shaft so that I could press-fit it into a bearing. The surface properties of aluminum just aren't good enough (at least for me) for rotating or direct-contact sliding. |
I would agree that 6061 alloy aluminum is a poor choice for shafts, but 2024 alloy aluminum and particularly 7075-T6 have excellent material properties that are competitive with many steel alloys. These two aluminum alloys are much harder and have significantly higher yield strengths than 6061.
I've been using 2024 and 7075 for shafts on FRC robots since I was in college in 2010, and have never had one fail. Plus, I absolutely love machining 7075 aluminum on mills and lathes. With good carbide tools, you can machine it like a hot knife through butter, as it does not have any of the galling issues that plague softer aluminum alloys. It's my second favorite material to machine after Delrin.
// Note: I didn't directly link to the Matweb pages for 2024 and 7075 since apparently the links are tied to cookies and 404 after a while.