damaged edge on stainless steel blade

First my compliments on choice of spouses!

And for my own understanding, this butter curl was raised off the edge i.e. a shallow gouge? It isn't damage to the edge itself, but is "behind" the edge toward the spine?

Correct. Just missed the edge, at almost the same angle as the bevel. Her blade was vertical, she blocked my blade which was coming down from above at maybe 30 degrees from vertical, and the hardened edge on my blade "bit" into the soft stainless instead of glancing off.

Lesson learned: besides the obvious dangers, this is why we don't use live steel for practice.

And I shall relay your compliment to Herself.

A photo would help.

You could clean and refill with a filler rod of stainless. However you will notice the fill. Steel has a grain, just like wood. Also you will see that all steel is not necessarily the same color. There may be a bit of discoloration around the area of the weld, but if done well you should be able to "buff" it out.

You say this is a hand forged blade? Do you mean properly folded, heated, hammered....?

Folded, no. With modern steelmaking you don't necessarily have to do that. It's one homogenous piece of stainless. But yeah, heated in a forge, hammered and drawn to the proper shape, then given a final edge with a file and polished. It holds an edge "okay"- about like a Swiss Army Knife.

Some "wall hanger" swords are made from low-grade steel plate, cut out with a bandsaw and shaped with a belt grinder.

If money were no object, we would each have a collection of custom-made blades- pattern welded, damascus, etc.

Thanks for the tip. I have a friend who shoud be able to MIG/TIG weld the wound with stainless.

You really need to know what grade of stainless it is . If it is Martensitic stainless it can be re hardened by heating and quenching and tempering. If it it is a type that cannot be hardened by heat treatment it has probably been hardened by being hammered and drawn [as you suggested], if you attempt a weld in one spot it will soften there and I cannot see how you would harden it again. But am open to suggestions.

Could be welded i.e. arc, or could be heat welded on the forge - back to the smith

Why not remove the "curl" and leave the blade scared. Sounds to me like it earned it.

When you remove the curl, why noy take it to a metallurgist, they might be able to tell you the exact composition. Might be pricy and the sample size may be to small. Might be worth a drive though.

You say the blade is soft, okay then a careful peening, manipulating the metal back to original position may produce a repair.

As others have related the specific series of stainless is crucial. Some stainless requires a heating then a slow cool to gain hardness and this type will become annealed if heated and quenched.

Take to capable scrap metal yard and have tang analyzed.

Assuming this is the same basic shape, length, and function as food/general use/pull out from horizontal sheathed position behind the back and thrust through opponent in close combat as the Norse/Viking/Saxon Scramasax: - and might the Lady favor us with a photo of her pride and joy?

Anyway, whether it'll need to just take an edge, but not necessarily be the primary weapon for slicing that needs an ultra-hard edge that 'keeps,' is obviously not the issue. Knowledge of the alloy used to create it, is. Your statement that it is "hand forged" yet ductile enough for a hardened (martensitic) edge to have cut into it is unfortunately - as you know - not sufficient to determine proper alloy for fill-in MiG'ing, but I kind of like the suggestion above to forge-work it back under moderate localized heating and buff it, leaving the inevitable small scar, since reforging the entire blade is a bit extreme. Filing it off and filling would "work," as you noted, and would likely be barely noticeable, even if the coloring left a hint of repair after buffing that she could show off ;)

To keep this from happening again, you need to first determine if perhaps the blacksmith used a maraging stainless as his stock material, since that requires a different process than austenitic stainless, and will not respond predictably to an "edge quench." Maraging steels are an interesting choice for utility and fighting blades that do NOT require a hard edge, but need superior strength and toughness without losing malleability. It is possible that you have this option - it is a separate class from the 200 and 300 series of low carbon ultra-high strength stainless, which gets its eventual strength from "precipitation" hardening (super-saturation) rather than carbon. It'll have multiple inter-metallics in the lattice. This is not uncommon in appropriate blades, as these "maraging" steel alloys are required in foil and épée because the crack propagation an order of magnitude slower than carbon steels, so you get fewer accidents from broken blades in sparring.

From a purely practical/mechanical property test, then, "Does it hold a good cutting edge?" may give you an indication that it 'may' be a maraging stainless.

If it is a maraging alloy, and you want to add some 'case' hardness, you can heat it up just enough after repair/rework to get the surface nitrided. This will still leave it able a fine surface to be polished. The full process takes the steel through annealing at ~800°C for a half hour to get austenite then air cooling to room temp to get a ductile (untwinned) martensitic structure. AFTER this you re-raise it for precipitation hardening for several hours around 500°C to get the fine nitrides along the martensite boundaries.

In case it's a standard 200 or 300 series (likely 304), you'll want to determine the composition. Higher Carbon content can cause carbonization if you raise the temp for welding repair, as the chromium runs to the carbon at the work boundaries and depletes the corrosion resistance of the surrounding matrix.

Regardless, for really accurate alloy ID you'll need to find a commercial welding & repair service in your area with lab/engineering staff, or a large metal scrap recycling center. They are most likely to have invested in a portable XRF device for identifying alloys for repair or analysis or for more profitable sorting of various steel alloys.

If you call around, you may find one with a Niton unit as described in this article:

http://www.thefabricator.com/TestingMeasuring/TestingMeasuring_Article.cfm?ID=1243

or an equivalent unit, such as the SPECTRO xSORT, or the Pocket-III from Skyray XRF.

Sometimes you can get a list of "references" - i.e. happy customers - by calling the manufacturer of the device that does the job you want, and you can then call the customer in your area to see if they'll hit it with the analyzer for you (maybe even for free ;).

Hmmmm, stainless steel again!! well, to each thier own. Interesting, a battle with the wife involving sharp edged weapons, I think I'll talk mine into it. Enough dreaming.......having worked on swords and knives for some decades, I have yet to find a blade that had a peel back like you are describing. It does sound as if the stainless is of the non hardening type. I have found that in the stainless I forged, it would harden just sitting in the air, somewhere around a rockwell C scale 58/60, almost too hard. So you had a peel back, and want to repair it. I like the suggestion of working back down and welding it, though I agree with someone that said smooth it out, it is a permenant battle scar to be worn with honor. If the blade is non hardening stainless , it can be easily welded modern method and polished with minimal discoloration to show. I personally have not had much luck with forge welding a scar similar to what you describe back in place, you end up doing so much reworking of the edge you may as well make a new blade. I have on occasion tried to modern weld a high carbon steel blade, but without much success. I find that the internal stresses will cause the blade to give after some time, if not during the hardening/tempering process. I am intriqued though, keep me informed of what you decide to try and how it works.

Thanks for the great replies. I think I will try heating the curl and peening back into place. That and a little file work should do the trick. Do I need to use some kind of flux?

In the extremely unlikely event "Baby" is called on for battle again, a few "battle scars" won't mar the function of the blade, so I think I will leave the edge temper alone.

Will try to get a pic of "Baby" for you folks.

Here is my blade that did the damage: http://www.knifecenter.com/kc_new/store_detail.html?s=CISH001PP

No flux just talc

I think you can weld this successfully with a TIG welder and some 308 filler metal. If the stainless is this soft I doubt that it has any more hardening on the edge other than the acquired hardness from the forging of the blade. If you are careful and get a welder that knows what he is doing, by utilizing low amps he should be able to really minimize the HAZ created by the welding heat and make a very good repair.