this is strange need advice

rotor

rotor

Joined
Mar 18, 1999
Messages
184
View

i ran into this quandry to which i had no explaination this is a blade made from a farriers rasp it was ground out without annealing it was x3 normalized x3 quenched in some Goddard goop with the third quench being edge an quench when i was doing some cleaning up after heat treat i noticed a wavey pattern in the steel i thought it was made by the course scotchbrite belt but it would not go away i hand rubbed the bade to 800 grit so i etchted to see what would happen and this is the result im stumped any help or advice Russ
 
The real question is...
Can you do it again?
:D
;)
Looks great to me, if it holds an edge etc. you're set!
 
I've seen the blade, he's not worried about it, he wants to know why a regular bar of steel has a pattern in it like damascus. It's gorgeous!!! Neat wavy little lines in the choil area and the tip.Umm, oh yeah, I wanna know too cause I've got one of the exact same files! :D
 
You mean you quenched the blade edge first?
I'm no expert, being a real beginner and knowing some theory but very little practice, but this seems to me to be some sort of hamon, that is: temper line, the wavy pattern you see on japanese blades.
What you probably did by immersing the knife in the quenching medium edge first was to obtain a differential tempering.
The edge of the knife got martensitic while the rest of the blade remained perlitic, or at least with a little martensite.
The wavyes you see are the boundary between martensitic and perlitic zones.
Probably the medium boiled up and convection and bubbles differentailly hardened the blade.
Did you stir the blade in the quenching medium?
Did you immerse it slowly or quickly?
Did you esitate fo an instant?
It may do a lot of difference if you did one of these things, and may be useful if you want to repeat the effect.
Very nice anyway.
I should consider making another test blade and make some destructive testing to see what it's capable of. :)
If you see a substantial difference in hardness between the edge and the spine, you have differential hardening.
Hamon isn't immediately apparent, but pops out if etching the balde with mild acid or polishing it.
 
I have had similar things happen with my file knives,I wasn't sure myself what was going on,The only thing I can figure was that i had my heat wrong for the steel or that it was a water quench steel and I had oil quenched it.I finally concluded that it was the grain in the steel showing up and sincr it didn't hurt the blades performance just left that cool look.
I have had some other stels get a spotty or pitty look on the tip of the knife and finaly figured out that i was overheating the tip and oart of the cutting edge when getting up to my quenching heat,you might watch and make sure that you aren't getting the thin spots a little warmer while trying to get the back up to color..
Bruce
 
i did the heat treat in my forge i cut the pressure way back brought the blade up slowly constantly checking till it reached non magnetic to make sure i wasnt over heating.oh yeah the pattern is all the way from the edge to the spine tip to choil.
 
Sounds like it is just a cool grain pattern in the steel they used for the file,As long as it heat treated and tempered good and will hold a edge just go with it and see if it happens on another file...Go kidnap the one L6 has,just tell him you need to test another one to see if it does the same thing....:D :D :D
Bruce
 
Hey Russ, that is a cool effect! Was that rasp an antique? The age and manner in which the steel was manufactured may have a bearing on it.

Guy Thomas
 
Quick - tell us what kind of rasp that was (maker etc) - I know where there are a couple of buckets of old rasp's.
 
I wonder if that could be the stamping on the file showing through the grain structure, that would explain the waviness but maybe not the lines themselves. If you can repeat that tell how!

TLM
 
Now that you said it I can see in the picture the strange waves going all the way up to the spine...
No hamon :p
 
Just curious, but did you grind the teeth off before forging, or was it stock removal only? And please excuse my asking this, but did you check to see if it was high carbon steel? Some farriers rasps are only case hardened.
 
it was a save edge rasp it was done by stock removal method as far i can tell it was not that old it still had some hoof in the teeth i got about 20 from a friend he got them from the stables that he keeps his horse at. i had called the company to get a chemical analysis of it but they wouldnt fess it up but said the steel should make a good knife blade.i did test the blde out they snap clean when you try to bend in a vise really tight grain structure i was loking in Wayne Goddards the wonder of kife making thres a close up picture of some shear steel it resembles it im wondering if where ever they get there stock from some one put a piece mystry steel in the batch you know that piece of steel thats been in the corner for ever but im going to try another piece and post the results
 
I'd check J.D. Verhoeven, A.H. Pendray, and W.E. Daukschs' article on wootz. It looks like it has an impurity pattern like they discuss. Some kinds of vanadium bearing steels I'm told can have such patterns due to micro segregation of grain, but damned if I can figure out how without laminating it.
The article can be found at: http://www.tms.org/pubs/journals/JOM/9809/Verhoeven-9809.html
Very cool, by the way.
 
The mark's were probley made ,when the rasp was made as it was probley
in a machine that pressed it all at one time.As a result the line's that you see are probley steel compressed harder then the surrounding metal.That's my opinon.Maybe someone else has a different ideal,by the way I think it look's great.And where can I get one just like it.
Thanks Wayne
 
Could it not be "simple" alloy banding? Let me quote mastersmith Howard Clark regarding what alloy banding is: "It IS a pattern, that results from alloy segregation in the steel when it was made, and it is commonly referred to as alloy banding. Many varieties of modern steel will display this phenomenon if sufficiently polished and then etched." I've seen something similar on a 1050 blade (though not as regular as that, and it was too faint to be photographied...)

JD
 
This is what they told me when I emailed them about it.
"Dear Osbourn,

Thanks for your feedback. No, the rasps are not composite laminate
steel. In
order to make good quality files and rasps you need to use very high
quality
high carbon steel. Steel for rasps has a little lower carbon content
than
steel used for regular files. And yes, file steel is great for knives.

Best regards,
Mikko Laitasalo
Sales & Marketing Mgr.
TRG TOOL CO./ SAVE EDGE"

A very polite, if intentionally vague, response. My interpretation is that they're using something akin to 1095 for files, and 1060 for rasps, but likely richer alloys. This would explain why their rasps have such good reps, though. Most imports use 1018 for rasps.
I'm sticking with the vanadium grain separation theory. Much like Joss said, only alloying ingredients could make the affect more pronounced. And it was probably your multiple heat treat cycles that brought it out.
I could be wrong, though. That happens often enough. I'm interested to see if it's repeatable.
 
You must log in or register to reply here.
Back
Top