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Heat Treat Issue?

Fri Jun 14, 2013 4:42 pm

O.k Gents, I'm hoping for some opinions on a recent issue I've encountered with one of my EDC blades I've owned for many months now. I will mention the smith is an ABS Master, but I will withhold the name for now because he's asked me to ship the blade back to him for evaluation and I'll be curious to see how he handles the situation.

Although I could have modified the primary edge that came with his blade, I decided to use it as is. I started by employing the tip to drill into some relatively soft wood for light bush-craft chores; nothing hard core. Immediately the tip failed and actually crumbled (verses rolling) and left behind a black burr where the tip broke (small break, small blade under 4"). I figured it was simply due to the grind that had been supplied so I went ahead and restored the tip and kept on rockin. Well, after 4 or 5 tip restorations over the last 6 months, I began suspecting other issues at play. This black burr remaining at the tip became a constant trait. Keep in mind I'm very accustomed to restoring tips successfully over the years and I've done so on a multitude of different steels.

The second clue I'll mention is that I noticed the edge retention was noticeably less than other blades I've owned from this smith of the same steel. The combination of the blade's inability to hold an acute tip and the lesser edge retention has me wondering if the heat treat/tempering is suspect. Perhaps the typical HRC range fell short on this blade. Whereas I will refrain from identifying the steel type at this point, I will mention it is hand-forged verses stock removal.

Josh

Re: Heat Treat Issue?

Fri Jun 14, 2013 5:35 pm

Without a lot more information, this is a total guess and should be viewed as nothing but a conversation amongst knife nuts.

Barring a failed design, it could be the heat treat. Did he get it hot enough? Did he temper it properly. If he's using an oven and a normal, well used steel....this isn't likely. If he's using the forge for the HT, it could be more likely. Did he get it into quench fast enough? There are so many things that can go wrong during a HT. However, very few truly ruin a blade from an established knife maker. If he didn't get the knife to quench quite fast enough, it wouldn't ruin the blade...at least typically it wouldn't. It just wouldn't be AS hard. I've seen bad HT's on knives...but they're not really common.

It could also be that it got too hot during grinding and ruined the temper. Certainly possible. I've smoked the tip on two knives. It's pretty obvious right away though. The steel turns colors and you see that immediately. If he was grinding with gloves on, this can happen easier than grinding without gloves.

It could also be a problem during forging. Too high of heat, for too long can decarb the steel. Need carbon to make steel.

It could be some type of contamination during forging.

It could be a bad piece of steel. It's happened before.

Anywho, my thoughts....although they might be worthless as I don't forge anything. :)

Re: Heat Treat Issue?

Fri Jun 14, 2013 6:21 pm

Thanks Adam, that's exactly what I was hoping this could be, just some harmless speculation among enthusiasts. I know I'm (purposely) leaving out some of the details and obviously a HT is a subject as vast and deep as the ocean. Having said that, I was guessing tempering may be the culprit, but that opinion is coming from limited knowledge since I have not had the privilege (yet) to put my hand to the forge.
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