Straightening?

You need to do the final work on the hardened blade rather than the soft state.

-- Bob May Losing weight is easy! If you ever want to lose weight, eat and drink less. Works every time it is tried!

Reheat it and straighten it while hot. Then, heat it up again and bury in powdered lime or vermiculite. Leave it for at least 4 hours.

This is called Annealing and will remove any stresses in the blade from the forging process.

Clean up the blade. Then re-harden it, this time making sure not to have an uneven heat on either side of the blade before you quench.

Tempering in the oven is fine.

Quenching high carbon steel without warping it is an art. You can't just chunk the blade into the quench any old way. The exact way you'd do it depends on the particular blade shape, thickness, and size, but for most of the blades I've made, I get best results by *slicing* it into the coolant edge first, then vigorously moving it around once it is submerged.

I doubt you'll be able to remove the warp in hardened

1090 by cold working. I suspect you're going to have to anneal it, straighten it, and reheat treat it.

Gary

Reheat it and straighten it while hot.

Vermiculite? Lime? We don't use no stinkin' vermicu...whatever. Round these parts we wrap it in rolled up panther hide.

Bob Swinney

[...]

Can you "wear out" a piece of metal by repeatedly heat treating it, annealing it, heat treating it, and so on? Or is it something that's yes for some metals, no for others?

During forging, all stresses are inherently removed because the metal is always above annealing temperature, so this is N/A as far as I know. I have to to finishing work (aside from the polishing) in an annealed state because we don't seem to have a grinder. . .

Um, not an issue.. there's not going to be more than 50 degrees across the thickness. (Note the warp is like bending the thickness. Not like an arc'd Samurai sword (called ???).)

The point is moot now since I tried tapping it between three blocks of wood, breaking it.. I'll have to go forge weld it somehow, or otherwise make a new one...sigh...

Tim

-- "I have misplaced my pants." - Homer Simpson | Electronics,

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You're going to lose some of the surface to scale every time you heat it, unless you have a controlled atmosphere furnace. You have to allow for that when you choose the stock.

If you *overheat* steel, ie bring it to a white heat, you'll burn some of the carbon out of it, as well as produce a lot more scale. That's not an issue at normal forging and heat treating temperatures.

Also, if you hold steel above the critical temperature too long, you'll get grain growth, which weakens it. This can be corrected by annealing and reheat treating.

Intricate decorative pieces may have 50 or more "heats" involved in producing them. The metal doesn't "wear out", though as I noted there will be some losses to scale formation with each heat.

Gary

With my slow going I've probably heated a lot more times than that... and the surface still spark tests 1080/1090 in carbon content. Not even 1040/60 range anywhere. So there's not really much loss at all.

Tim

-- "I have misplaced my pants." - Homer Simpson | Electronics,

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