Induction hardened steel. Usable?

[Reading Creek Forger]

My son gave me about 6 feet of what he called induction hardened steel.  It was broken in a few pieces but was a shaft from a piece of heavy equipment.  Its approximately 1.25 inches in diameter. From what I have read Induction Hardening is similar to case hardening except it may be a little thicker hardened surface.  I also read that it is usually done to medium carbon steel.  1037-1048 according to the website Though hard the surface can be brittle.  It can be hardened in water, ,oil or a polymer and is sometimes coated with chrome or a polymer.  the pieces I have not chrome on the surface so I guess they are polymer coated.   I think that calling it a polymer means a plastic like substance but I don't know.  My questions are:  Is this a suitable stock for Blacksmithing?  Can or do I need to anneal/normalize it before I use it.  I assume if I can use the shaft it would be suitable for top or bottom fullers but I really don't know.  Does anyone know more about this stuff?  

[Will W.]

From the small amount of research ive done on the subject, it seems that induction hardening is a process used to isolate heat treatment to certain parts of whatever it is youre heat treating. So in a thick cross section like an axle, it could be used to harden only, say, half of the diameter of said stock, leaving the center soft. So saying it is similar to case hardening is not far off. 

It could be done with literally any steel, but an axle or shaft is likely medium carbon steel. 

Is it possible that your piece isnt coated or plated at all? Is there any rust on it, surface rust included?

Induction hardening is a different approach to hardening, but the process is still the same. Whatever parts of the steel are hardened, in this case it seems likely that its only the outside of the shaft, they still form martensite, just like regular hardening. This leads me to beleive that a few normalization cycles should take the steel back to normal, where you can turn it into whatever you want and HT it.

I am no expert on this subject, but i hope the little bit i do know helps in some way. 

P.S. a polymer is just a chemistry term for a certain type of macromolecule composed of repeating units held in place by covalent bonds. Its a category. Most plastics are indeed polymers, but not all polymers are plastics. DNA is a polymer, for example. 

 

[swedefiddle]

Good Morning,

Hardening anything is only possible if the subject is above the critical temperature and the quench rate is sufficient to lock the electrons into their lattice. A quench rate is ???hundred degrees per second of quench. Hardening to the core is not possible, as it is not achievable for the core to have the same quench rate as the surface or near the surface. Typically depth of hardness is measured in thousandths of an inch. There is no maximum number of times a piece can be Heat Treated. To remove the Hardness, heat to above critical temperature and let cool slowly (for a Water or Oil hardening Steel).

Induction Hardening is just a different procedure to get something above critical temperature, without heating the complete subject/piece.

Neil

[ThomasPowers]

Depends on the alloy.  Many steels through harden quite well especially the ones that use a slower quenchant like oil or air.

[Reading Creek Forger]

Thanks Will, Swede (Neil) and Thomas.  What you all have said seems to agree with my interpretation of what I have read on the subject.  So long as its safe and I can normalize it I think I can use the stuff.  Neil, as far as your question on the presence of rust:  None that I can see on the shaft but there is some at the yolk end and at the opposite end which is threaded.  Those ends are not coated with the same brown color as the shaft.  I spoke to my son again today about it and he said it broke when he tried to straighten it at work so whatever it is it appears to be somewhat brittle.  I am going to put a piece into an outdoor coal fire, get it hot then let it cool slowly and give it a shot.  Thanks again