where can I find a scale that will translate what the rockwell hardness of a certain steel the load it will carry, into tensile strength? I can't seem to find the info online ive been searching for a couple hours.

for instance lets say we have a a 1566 steel shaft that has a Rockwell hardness of 60-65C how do I find out what the conversion is into wieght it will handle and how do I find the tensile strength

I know there are some people in here that know these things, so I'm asking for some help

 

all you need is matweb.com
Create a user name and pw and you're all set!
It's great for materials research.

 

thank you

 

It's not that simple. If a shaft is Rc 60-65 on the surface and is designed to transmit torque or is loaded in bending, the shaft is probably not that hard all the way through because it would be very brittle. In other words, it is probably case hardened to give a hard wear surface someplace on the outside. In the case of 1566, which will thru harden if heated in a furnace and quenched, I suspect the area was induction hardened. If it truly is thru hardened to Rc60+ is has a compressive strength of about 300,000 psi, but it would not generally be used in a tensile or torsional application. The total strength depends on the "core hardness". Usually that requires destructive testing to determine.

What, specifically is the shaft used for? 1566 is not a common aftermarket steel, but could be an OEM transmission shaft or some similar thing.

 

well I'm looking for a shaft capable of supporting the weight of the fourth gen door when it's six inches out on the rod, with a hardness on the outside to take the wear from an air bearing. The rod will be taking the load from the side which I know makes it prone to wear to begin with. I figured if I could get an idea of how much stress a piece could take I could make a rough judgement on what material I was looking at needing.

It's not being used on anything for the drivetrain or suspension, just for a new hinge idea for the door, I'd like it to be overkill so it'll last for quite awhile

Of course if anyone has suggestions I'm open to them, but it would appear that this would work rather well from a quick look

 

Thoughts:

How much sag or deflection can you stand when the door is supported? That will pretty much determine the size of a beam or shaft you need. That's way more important than the hardness. You'll probably want to use a tube. Anyone doing the design would have to know weights, dimensions, etc. If you plan to cantilever the door, the mounting to the body will be critical also.

Air bearings don't really need deep hardness. Industrial hard chrome plating should be good. It'll also protect the steel you'll be using from corrosion, and you can polish it if you like.

The last thing you need is a very hard, brittle highly loaded shaft.

Good luck!