Interesting observation from the https://en.wikipedia.org/wiki/Specific_strength table: Oak (wood) has a higher specific strength than aluminum 6061-T6 and Chromoly (4130)! Balsa (wood) has a higher specific strength than most metals and almost rivals carbon-epoxy composites. Of course wood's strength depends on the grain structure (non-isometric), but still. That's pretty cool. Maybe we need to go back to the future and use wood in transportation.
Gary -----Original Message----- From: EV <[email protected]> On Behalf Of Bill Dube via EV Sent: Tuesday, December 3, 2019 3:00 PM To: [email protected] Cc: Bill Dube <[email protected]> Subject: [EVDL] Chrome-moly vs. Steel (was: Light weight electric motorcycle. DIY) Chrome-moly steel is about double the specific strength (ratio of ultimate strength divided by density) of mild steel. That's why they often use chrome-moly in airplanes, and never use mild steel. https://nam01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fen.wikipedia.org%2Fwiki%2FSpecific_strength&data=02%7C01%7Cgln103%40psu.edu%7Cf55cd34d8fed4ed144e708d7782b5ed7%7C7cf48d453ddb4389a9c1c115526eb52e%7C0%7C0%7C637109999974629230&sdata=GBD3treZq5TBYBHiwFt8V1JTheybre8Z3sqJ38vW2uk%3D&reserved=0 As you can see from the chart, mild steel has a specific strength of 71-85 kN m/kg, while low-carbon steel has a specific strength of 46 kN m/kg. Looking further down the chart, you can see why they use carbon fiber composite (785 kN m/kg) to build modern airplanes. Chrome-moly (4130) is often chosen for its ease of fabrication and its forgiving nature when abused. It can be welded (or brazed) without subsequent heat treatment, and it deforms ~25% before failure. (It stretches like taffy before it comes apart.) It also has a high fatigue resistance. Bill D. About double On 12/4/2019 7:31 AM, Paul Compton via EV wrote: > On Tue, 3 Dec 2019 at 03:27, Lawrence Rhodes via EV <[email protected]> wrote: > >> Using chromoly will reduce the weight. > Oh, is Chrome Molybdenum Steel somehow magically lighter than mild Steel? > _______________________________________________ UNSUBSCRIBE: https://nam01.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.evdl.org%2Fhelp%2Findex.html%23usub&data=02%7C01%7Cgln103%40psu.edu%7Cf55cd34d8fed4ed144e708d7782b5ed7%7C7cf48d453ddb4389a9c1c115526eb52e%7C0%7C0%7C637109999974629230&sdata=c8TldHeDUNEEQLG7maI7TTMpy4aZ5IZnspankzGZxaE%3D&reserved=0 ARCHIVE: https://nam01.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.evdl.org%2Farchive%2Findex.html&data=02%7C01%7Cgln103%40psu.edu%7Cf55cd34d8fed4ed144e708d7782b5ed7%7C7cf48d453ddb4389a9c1c115526eb52e%7C0%7C0%7C637109999974629230&sdata=OAx3u5FzleoiHc7Kh8sqoBS4ZZnHcLXhfVDqNHYwVk0%3D&reserved=0 INFO: https://nam01.safelinks.protection.outlook.com/?url=http%3A%2F%2Flists.evdl.org%2Flistinfo.cgi%2Fev-evdl.org&data=02%7C01%7Cgln103%40psu.edu%7Cf55cd34d8fed4ed144e708d7782b5ed7%7C7cf48d453ddb4389a9c1c115526eb52e%7C0%7C0%7C637109999974629230&sdata=F5hEdIY3PibVp9C4EBOcfzRPs9UeF%2Bp9W3V2wyvx%2Bsc%3D&reserved=0 Please discuss EV drag racing at NEDRA (https://nam01.safelinks.protection.outlook.com/?url=http%3A%2F%2Fgroups.yahoo.com%2Fgroup%2FNEDRA&data=02%7C01%7Cgln103%40psu.edu%7Cf55cd34d8fed4ed144e708d7782b5ed7%7C7cf48d453ddb4389a9c1c115526eb52e%7C0%7C0%7C637109999974629230&sdata=pyC8r6uP7h4jRV9FIF9%2FIeiA%2BxQL2QUcbYSXRCHlUHI%3D&reserved=0) _______________________________________________ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub ARCHIVE: http://www.evdl.org/archive/index.html INFO: http://lists.evdl.org/listinfo.cgi/ev-evdl.org Please discuss EV drag racing at NEDRA (http://groups.yahoo.com/group/NEDRA)
