Failed blade

[T.J.watts]

This blade was so I thought my first successfully forge welded blade. Three pieces,  A36 with a 1095 core. Everything was going great and turning out how I wanted, then I quenched, snap tempered and bead blasted.(very fine media) There is now a crack down the center of the core, not the weld. I am unsure what caused this, maybe different contraction rates during the quench or maybe drawn too cold. Has anyone ran in to this and figured out what happened? This is extremely frustrating and disappointing to say the least in a polite manor. At the very least I now have a nice pattern to use in the future.

Edited October 22, 2015 by T.J.watts

[Richard Furrer]

core splitting is not uncommon with severe quenches or drastically different core/side pieces...happens a lot with 52100 and stainless sides.

I suggest not using A36 as you really do not know what it is. 1018 or similar would be better.

 

Ric

[T.J.watts]

That was just what I had at the time, but I'll probably try this again with 1018 or maybe 50k.

[Michael Cochran]

That's a real shame. It looks like it would've been a good little knife.

[Charles R. Stevens]

That is a bumber. 

[T.J.watts]

The plan was to use 4140 for the hilt, copper spacer, black buffalo horn, copper and black ash burl then copper, bone, copper, hilt. I'll try it again just because I was really liking the blade and the idea for the handle.

[HWooldridge]

Maybe try grinding a bit more on the spine to see if it is a surface crack.  At this point, you don't have much to lose.

[ThomasPowers]

What did you quench it in?

[Steve Sells]

also suggest do a real temper cycle,  When we rush we tend to fail more, there is no substitute for time

[jeremy k]

Polish the spine to a mirror finish - then etch it to see where the crack actually is in comparison to where the different steels are, as the etch will show the line of were the steel types meet each other.

[T.J.watts]

The pictures aren't very good but you can see the layers and the crack is right through the core. I thought about grinding the crack but it goes in to the tang so I wouldn't even try to save it. the quench was in hydraulic oil then put in a rod over for the snap temper, I hadn't made it to the actual temper yet when I found the crack. The plan was to do two temper cycles at 375 for an hour each when I got home but I didn't make it that far. I wish I could save the blade but I cant think of a way to do so without leaving a detrimental flaw. I'll try again and have a nice pattern to work with.

[Frosty]

Would putting it in another billet work?

Yeah, that's a non-bladesmith guy question. Just wondering.

Frosty The Lucky.

[Steve Sells]

Actually frosty if you visit my web site, there is pattern I call a psychedelic twist,  it is alternating layers of 1/8 inch thick blade steel, and failed "Other damascus" blades or billets rolled to 1/8 inch thick, that have been forge welded into a new billet,  given a random twist and made into a blade if it takes a good weld ...  I never throw away damascus steel

[Frosty]

You mean my intuitive reasoning was right?! I saw the Psychedelic Chevron but no twist. Nice patterns all round Steve.

Frosty The Lucky.

[T.J.watts]

I wasn't sure if rewelding it was an option, I'm not very skilled with it yet. Do you guys think the snap temper or the hydraulic fluid caused the crack?

[Frosty]

What's a snap temper? I don't do a lot of hardening but for what I do I use fryer oil from a local super market. I was hoping to get their doughnut oil but no, my shop smells like burritos, fish, fries, etc. Oh well. They were happy to fill a 5gl jug with canola oil when they changed oil.

Hyd fluid can make dangerous bad smoke though it does a decent job of quenching it has a high flash temp. Of course you could just buy some heat treat or heat transfer oil but what fun would that be. eh?

Frosty The Lucky.

[T.J.watts]

From what I understand the snap temper is kinda like the dry ice quench, it helps force the hardening process to finish. Don't quote me on that I'm probably totally wrong .If someone else can explain it better that would be great.

[Steve Sells]

terrible with names, cant even remember my own.. here it is Frosty and others..  http://fenrisforge.com/Damascus Patterns_files/c-twist.jpg

 

[Frosty]

That's a pretty good name for the pattern Steve it fits nicely.

Frosty The Lucky.

[DanielC]

I have been working sanmai a LOT lately. Your choice in steels seems to be the hardest combination, or rather the highest fail rate I have encountered for san-mai. Sometimes, not all the time I run into this. I even caught the phenomena in the act on camera, literally listening to the crack slowly tink open. As Ric suggested, I had also switched from A36 to 1018 from my local big steel supplier. I had less problems then. Not gone, but less. To date, the only blades I have had crack at the core were this combination. 100% success rate so far using wrought as the jacket.

[Charlotte]

WOW!  Great pic!  You should get a prize for best presentation of a "Learning Experience"  Thank you.

[Jim L.]

I agree with the regrinding of the spine,  polish, then re-etch.  This will make a difinitive diagnosis of splitting layers 

 

Jim l.

[T.J.watts]

I have one piece of wrought from rebuilding my post vise, and was thinking about using that for the next attempt. Lesson learned, I just used the A36 cause it was under my table. Probably won't do that again.

[ThomasPowers]

Used to find a lot of wrought iron in OK when I worked in the oilpatch---lots of abandoned ag scrap piles from the 30's...

[T.J.watts]

I looked in to the snap temper more. I had it backwards, the snap temper is meant to help prevent the blade from cracking while waiting to be tempered. Thomas I need to talk to some of the farmers around here and see if I can go scrounging in some scrap piles.