small problem with steel from forge

D

DaQo'tah Forge

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Aug 26, 2002
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hi this is DaQo'tah

I just had a small little problem with some steel that I just forged this week..

I could use a little advice about what I have done wrong, and how to not do that again...


The Problem : I etched the blade to see how good a job I did with the heat treatments, and after buffing the blade noticed little "dots" along the blade edge

The dots look about the size of pin pricks, and are found along both sides of the blade...

I know this blade is junk....what did I do wrong?

The Forging: I use John Deere load control shafts ...the forge is my brand new NC Low Boy 3 burner...

I heat the steel, and hand poind it flat with a 10# hammer...

as I do the tang I quench a few times in coal oil

ground blade over-size then heat treated 3 times in texaco type "A" oil

tempered 2 times in 330 kitchen oven

dots were not noticed until I had the blade hair shaveing sharp and after it was etched to show temper line...



what did I do to make the dots show up?
 
The only way to be sure is to destroy it, that said, not sure. It may have been over heated, may be nothing wrong with forging or heat treat, not real familar with all the ends and outs of 5160.

I did a hawk a little while back out of a load shaft. I left the head in the etch for 4 hours to give it a real mountain man rustic look. It came out with a wierd damascus patterning, but tested out fine.
:confused:
 
I can't tell you what happened, but I believe you have what the Japanese call Nie. I'm not really qualified to say what they are precisely, but it is not a bad thing to my knowledge.
 
Could you show a pic?

By pin pricks, do you mean actual holes or purely a cosmetic effect?

I think it may simply be pits from rusting or etching or both.

Or they may be holes/mini-craters that have simply not been ground out after forging. They may be the remnants of what were larger hammer marks and oxidation since ground off.

I think some further "corrective" finishing may simply be in order, the knife is probably fine in my opinion.

Hope that helps. :cool:
 
well....to tell the truth...I did kinda forget the steel in the etch about an hour....

I had etched it for 10 min,,,but I didnt like what I saw,,,so I sanded it with 600 grit (600 grit was all I had in the house, not that I think 600 grit was the right stuff, it was just handy)sanpaper, then ment to only re-etch another 10 min, but got to writeing on my computer.....looked at the clock and noticed over an hour had passed?!!!


there is a very good chance that I might have over-cooked the blade in the forge...Im not sure.

It's my first blades in my new forge. I didnt think I had over-heated. The blades came out after each heat with the same color (More or less), except for one time, when I noticed there was a bit of sparking.


Now I knew at the time that the sparking of the steel was not a good sign.....

But it was not that sparky...a few sparks.

was any sparks at all a sign that over heated had happened?
 
Sounds like you need to bring your forging temperature in the forge down a bit. When the steel was sparking was it nearly white in color? As was said earlier this may just be cosmetic (maybe from the extended etch as you pointed out)and you didn't overheat the steel badly enough that it wasn't corrected in the heat treat. Howevr I would test the knife to destruction to find out, if it doesn't hold up to your expectations and to the level of other knives you have made then you've learned a valuable lesson.
 
DaQo'tah, Unless you severely overheated the blade then I think you are ok and what you may be seeing are "pits" in the steel. I use a lot of 5160, in particular J.D. load shafts, but I have used 5160 from many other sources. In my experience 5160 always "pits" to some degree in the hardened areas during the quench. These pits must be ground out after the quench to get down to smooth, quality steel. Just take care that you do not heat up the blade too much and ruin your temper when grinding.
 
If the pits weren't there before you etched you just etched it to long. 5160 isn't going to show much of a temper line if any. No need to sharpen the blade real well before etching since it will be lost in the etch.
 
DaQo'tah,
How did the brass rod test come out? 5150 I have used is sometimes mottled before polish.
Lynn
 
Fox......

Im going to go with your advice,,,,I have no idea what I might have done wrong becides what I have talked about...

I will run the blade edge into the belts to make a flat area along the whole cutting edge,,,then I will just grind down everything again like I did before.


Heres the deal, I never noticed the dots before the etch,,,I had a darn good knife...very good lines for one of my blades,,,but right after I buffed the blade out of the etch I saw the dots..

The dots are pin pricks,,,Im not sure they go all that deep into the steel,,,but clearly they are some type of holes....

I am going to forge another blade this week end, I will pay closer attention, this time there will be lower temps ,,and no chance of over heating...if the dots show up again?

then I dont know what else to do...

will let you know....
 
A little trick I learned while forging to keep from getting to hot. I hang a speaker magnet off of my forge cart and when I bring the steel out of the forge I check for non-magnetic. Once I get non-magnetic and observe the color for the light conditions I'm in I have a guid to go by for color during forging. I forge all 52100 and what little 5160 at criticle, or just a hair above non-magnetic.

5160 is very forgiving, but it does sound like you over heated it, what with sparks and all.
 
I over cook my damascus blades and when I etch them the dots are raised. Indicating they are harder than the back ground and don't etch as fast. If you are going the other way and the holes are etching into the steel it would seem that those points are softer and etching more quickly. This dose not give you an answer to why it happens . The short answer is I test the knife and it works well. I incorporate it in the pattern to imitate aboriginal dot art and wangina heads in the layers. I think it looks good so dose the paying customer.
 
 
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