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The Newbies Arena Are you new to knife making? Here is all the help you will need.

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  #1  
Old 04-14-2019, 06:26 AM
Rasmus Kristens Rasmus Kristens is offline
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I need to know what i did to ruin my blade..

I just did a HT on my 80crv2 blade and something did not go as planned.
i hope you can help explain to me what i did wrong.

I haven't seen this happen to any of my previous blades, but i tihnk it might be some serious hotspot which resultet in a lot of decarbonization.


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  #2  
Old 04-14-2019, 09:10 AM
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Crex Crex is offline
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Looks like "hot spots" where your heating is not even before quench. Using a coal forge? Easy to get air blast hot spots if you are not careful. Making a tunnel -oven with black iron pipe can be very helpful in regulating an even heat.


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  #3  
Old 04-14-2019, 09:37 AM
Rasmus Kristens Rasmus Kristens is offline
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I use a small DIY gasforge. It heats directly from the side of the oven. I think i didnt Pay enough attention when i heated the blade.
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  #4  
Old 04-14-2019, 12:26 PM
damon damon is offline
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for sure overheating! been there done that.

got pics of the forge you use?

reducing the heat a but might help prevent this, or inserting something to shield the blade from direct contact of the flame.

as for this one, you could write it off as a learning tool, and snap in in the middle of the hot spot, to see the internal grain structure. or, try several normalizing cycles to get the grain size back to where you want it.
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  #5  
Old 04-14-2019, 01:38 PM
Rasmus Kristens Rasmus Kristens is offline
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Damon. I guess its only overheating in the few spots right?

I just dont understand it, i bought 2 tempilsticks one for 1500 f and the other for 1600 f. The steel for this knife should be quenched between 1545-1615f. When i got the steel to non magnetic i gave it som more hestt and tried the 1500 f stick, it didnt smear as I saw in the videos it should, but burst in to flames and kinda crumbled. Then i tried the 1600f stick and nothing happened. I calculated that My steel was above 1500 f but for sure below 1600 f, then how can it overheat?

I Will try to present direct flame next time.
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Old 04-14-2019, 02:14 PM
Rasmus Kristens Rasmus Kristens is offline
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okay. That was pretty difficult both mentally and physically:-)
Those blades are tough!

I broke the blade 2 places. Can you have a look at the grin?
I think it looks pretty good. Very uniform light grey, no large grain. It d'dnt break clean, but took off a bit of the surface, does that mean anything?
Pretty hard taking a good picture of that..

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Old 04-14-2019, 02:17 PM
Doug Lester Doug Lester is offline
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Work your blade back and forth in the forge and even turn the edge top to bottom to heat evenly from both sides. I would also recommend that you try to spot decalesence which will give visual evidence that the steel has changed phases. Building a little larger forge can help in not having the flame blow directly on the blade.

Didn't see your pictures of the grain until I posted the last paragraph. The ends of the steel are a little out of focus so it's not easy to see the grain but from what I can see the grain looks large to me. If you want to make a standard to go by and have a old file that you can do without break it. That will give you a real good comparison to go by.

Doug


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Last edited by Doug Lester; 04-14-2019 at 02:22 PM. Reason: update reply
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  #8  
Old 04-15-2019, 01:21 AM
Rasmus Kristens Rasmus Kristens is offline
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I took a better picture.
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  #9  
Old 04-15-2019, 05:43 AM
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Do you have a way of regulating the heat in your forge? If not you will really have to pay close attention to how the decalesence moves through your blade as it transforms. If your blade is directly in contact with your torch flame you are going to have to constantly move your blade as Doug has stated in order to have this transformation occur evenly throughout the blade. Blade geometry plays a big roll in how this occurs as it heats up.
Yes, your grain growth is too large. I'm pretty sure someone posted comparative pictures on this forum a while back. I think you would find them and the explanations that accompany them very helpful.
80crv2 is very good blade steel and when you get the "recipe" right you should get much finer, velvet looking grain structure.
Don't get discouraged, you are learning from this. When you get it right it will all seem much simpler and you can get on with the next level.


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  #10  
Old 04-15-2019, 11:16 AM
Rasmus Kristens Rasmus Kristens is offline
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Thanks Crex. I'm already doing a new blade :-)
I ahve made some really good HT in the same forge on previous test blanks. THose i did by colour and nonmagnetic.
This time i wanted to try the Tempilsticks to hit the temperature even better, but that didn't go as planned..
I think what annoys me is, that the temperature for the steel I bought should be between 1545 and 1615 F. I didin't hit 1615 based on the Tempilsticks but it still overheated, thats what i don't understand..
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  #11  
Old 04-15-2019, 04:27 PM
Doug Lester Doug Lester is offline
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Going by color, which is influenced by ambient light, and loss of magnetism, which occurs below phase change, can be misleading. I haven't had much experience with Templisticks but I found them difficult to use. Best to do your heat treating after dark and learn to spot decalesence.

Doug


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  #12  
Old 04-18-2019, 03:35 PM
Rasmus Kristens Rasmus Kristens is offline
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I just ran a few test on some scrap steel. Just looking at the colour and trying to spot the phase change.
How are you supposed to see the change whn its in the forge?

I can easily spot the change when i take out the blade and let it cool, but how do you see the change inside the fire?

Hope you can give me some pointers.
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  #13  
Old 04-18-2019, 09:10 PM
Doug Lester Doug Lester is offline
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Yes, it is easier to spot recalesence than decalesence but they're the same thing only in reverce. If you watch the steel in the forge you will see the it dim and then brighten just as you did when you when you took the steel out of the forge. It's easier to spot in reduced light. The joke about it is that you heat treat on a moonless night but doing it after sundown is not a bad idea unless you can reduce the ambient light in the forge building without exposing yourself to carbon monoxide poisoning. Keep at it; you'll get it.

Doug


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