Hardox 500 Steel?

[Krunch]

This is kind of a metallurgy question, I guess. Not sure if this is the right forum, but I'm hoping.

I went to the local welding shop today hoping to buy a piece of an old truck leaf spring that I planned to make into a shipwright's "slick" ... basically a huge massive chisel, maybe 3" across the cutting edge and 3/8" thick with a wooden handle attached with screws. It needs to be heavy (for inertia) but it also needs to be good steel, and supposedly spring steel makes good wood cutting tools.

The boys there didn't have any truck springs, but they did have some special steel that they said was hard as heck, that they thought would make a good cutting tool. They said the steel was called "Hardox 500."

Is anyone here familiar with this steel, and can you tell me whether it will harden and temper into good woodworking steel?

Thanks for any info.

Jeff

[Krunch]

Edit: I found a PDF describing some of its properties. Sounds like good stuff to my uneducated eye!

[Zrexxer]

It's abrasion resistant plate, not tool steel. It's supplied as hard as it's going to get and they don't recommend re-heat-treating it. At the Brinell harness quoted it equates to about a Rockwell C 51 hardness, probably not as hard as you'd want. But hey, you're in it now... give it a shot and let us know how it works.

[Krunch]

Thanks for the reply Zrexxer.

I assume you're referring to their warnings:

"HARDOX 500 has obtained its mechanical properties by quenching and when necessary by means of subsequent tempering. The properties of the delivery conditon can not be retained after exposure to service or preheating temperatures in excess of 250°C (480°F). HARDOX 500 is not intended for further heat treatment."

Could it be that they're simply saying, "If you cook or grind out the temper or try to retemper, all bets are off, we don't warrantee the product and you're on your own"?

Surely if you heat it to cherry red and quench, you can get it harder than RC51, right?

[Not trying to argue, I'm a total newbie, but I'm just trying to understand.]

Thanks,

Jeff

[Broccoli1]

Junk yards tend to have Leaf Springs

[Zrexxer]

Surely if you heat it to cherry red and quench, you can get it harder than RC51, right?

Maybe, but maybe not... depends on the overall metallurgy, and unlike general purpose tool steels like O-1, this alloy was designed with a very specific application in mind. Rehardening could cause other problems, grain growth, cracking, who knows. It's been... a long time... since my metallurgy work in college, there are a lot of new things in the world since then.

Like I said... try it and see. A big tool like a slick isn't going to be quite as sensitive as a 2mm carving gouge. What have you got to lose besides some grinding at this point?

[Krunch]

OK, thank you. I will report back on this with my results.

[usmcpop]

Here's a Hardox data sheet. http://www.hardox.com/upload/Documen...DOX_UK_500.pdf

Moderate carbon, fairly high Manganese. I would get a leaf spring...

[greywynd]

Surely if you heat it to cherry red and quench, you can get it harder than RC51, right?

Actually, no. Final hardness is a function of the alloys in the steel, more so than the heat it's taken to to heat treat it. Actually, beyond that, the temperature of tempering will also affect final hardness. I'm assuming this 'chisel' is to be used on wood, so an extreme hardness is not necessarily a desired trait, especially when I can see a lot of prying etc being used. (If it's too hard it could snap when being pried with.)

I would think that likely something in the 54-58 range would be ideal, checking this page Lee Valley Chisel shows a hardness of Rc59.

The steel from the shop at 51 will work, but won't hold an edge quite like the harder stuff, but if you can live with having to sharpen it more often, go for it.

[Krunch]

OK, thanks gentlemen. I think I'll try to find a spring before investing all the work.

[Zrexxer]

Well, not to just keep raining on your parade, but spring steel ain't exactly ideal either. Yeah, I know it's been used, just like people make knives from old files, which isn't ideal either.

Problem is, spring steel is alloyed specifically for, well... springs. It's a medium alloy, medium carbon steel that's designed for incredible ductility and toughness - not hardness. 5160 spring steel is around 0.5 - 0.6 carbon, which really isn't high enough for the hardness needed for good edge-holding ability.

If this is something you're going to put a lot of work and time into and want it to be 100% right, then you'd be better off just buying an appropriate piece of tool steel flatstock to start with. Something like: http://www.use-enco.com/CGI/INPDFF?P...MITEM=416-0029

If you're just futzing around with the project for fun, what have you got to lose. You'll gain some experience in the process.

[Jeffw5555]

Just a caution about using spring steel for your chisel work. I noticed your mentioned quenching in an earlier post. If you quench spring steel for your chisel, I believe it will become too brittle, and may crack or split dangerously in use. You might research various tempering methods to optimize the hardness and flexibility needed for a wood chisel.

[usmcpop]

I saw some very wide floor chisels in the big box store the other day for around $10. depending on the size. Perhaps you could adapt one? Harbor Freight has one for $4.

You might also look around for a narrow version of one of these:

http://www.lowes.com/lowes/lkn?action=productDetail&productId=97009-302-1681900&lpage=none

I got one at either Lowes or Home Depot and another version at Harbor Freight. They are around 3 inches wide and perhaps 1/4" or so thick. I use them for chopping tree roots and digging post holes.

[Krunch]

Thanks guys.

Jeff, thanks for the tip on brittleness; what I planned to do is heat/quench, then temper in a 475-500°F oven for ~Rc 55-60.

I think I found a connection for a spring at the local school bus garage.

[Pin Head]

You could just do the old school blacksmith chisel temper:

Heat the entire blade to cherry red and then rapidly quench about 1 inch of the tip. Remove the blade and file off the scale from the tip so that you can observe the color on the bare steel. Let the residual heat in the unquenced part reheat the tip to draw it. When the tip gets to be a straw color, quench the entire part.