How to test to see if a material is really Chrome-moly or just steel?
I have a go-kart frame and I am trying to see if it is really chrome-moly or just regular steel. Is there anyway without harming the frame to see if its chrome-moly, something I can do to show its properties that it is chrome-moly?
It's difficult.... any reliable method would require lab equipment and destructive testing. The DIY way is just a crude possibility.
1) Industrial way: requires sample pieces for tests such as tensile or hardness test. Chrome-moly (usu. 4130 or 4140 Cr-Mo alloy steel) is stronger and harder than mild steel. But you still wouldn't know what alloy exactly without some metallurgical spectrograph.
2) DIY way: only if you can afford to scratch it a little (hope it's not nicely painted already) - do a simple hardness test. Pick an unimportant spot, sand off any coating/rust. Take a file and try to file the surface a little. Get a piece of mild steel and do the same thing and compare. If your part is indeed more difficult to file you know it's a harder material. Some technicians do this kind of thing and get a feel for the materials.... or instead of file, use a center-punch and see which surface dings easier.
Or, Cr-Mo tubing are supposed to be thin-walled - because material is strong. If your frame is thin and light, and you've driven it - and it stood up to the abuse, it's probably something better than mild steel.
3) Ask more people - mountain bike shop maybe? Cr-Mo tubes are used in bikes but maybe less popular now due to new lighter materials.
