Oil Hardening Steel

idbruce

Hello Everyone

In the past, I have had several occassions where I needed to harden a steel workpiece, and in the past, I always used O-1 tool steel for the workpiece and 11 second quenching oil for projects where hardening was necessary. I am under the assumption that O-1 tool steel is more porus as compared to other types of steel and readily accepts carbon deposits. I now have several workpieces that I would like to oil harden, but these workpieces are not O-1 tool steel. In fact, these workpieces are just your common threaded rod, which can be found at your local hardware store.

I am wondering whether or not the carbon would have any chance of penetrating the steel or if I'd just be wasting my time.

Bruce

pjv

Hi Bruce;

My belief is that if you need the rod to be hardened, then you are wasting your time with the rolled threaded rod that you buy at your local hardware store.

Peter

erco

That allthread is soft, but you should be able to case harden it somewhat. http://www.ehow.com/how_4579248_harden-steel-motor-oil.html

If you're using it as a leadscrew, keep everything well-lubed, or at least use a nice long delrin internally threaded follower. The point of contact on the threaded rod constantly changes, so at least you're distributing the wear & tear along the rod.

NWCCTV

Are you near any heat treating facilities? If you are, check with a local machine shop and speak to the QA manager. They will be able to tell you how it should be heat treated and may be able to put your rods in with a batch that they have going out. Machine shops around here are a plenty and have lots going out on a daily basis.

Mark_T

Quench hardening doesn't add carbon to the metal, it cools it fast enough to form martensitic microstructure in the surface layer (much harder than the bulk steel but very brittle). Water quench is more severe and tends to over-embritlle small pieces I think, but works the same way and no carbon present. IIRC the steel has to be heated above the eutectic point so no pearlite is present and its all one phase.

Carburizing and nitriding involve more prolonged heating in the presence of carbon and nitrogen rich materials - enough time for the atoms to diffuse into the metal - brief research suggests this is only useful for low-carbon steels like mild steel and pointless for tool steels which are already high enough in carbon. Maybe nitriding is sensible though for tool steel.

Standard studding is likely mild steel and suitable for hardening, but you will lose any surface finish and accuracy of screw pitch (matters for precision use).

This site seems useful and relevant:

http://www.roymech.co.uk/Useful_Tables/Matter/Hardening.html