Hollon Posted June 15, 2008 Share Posted June 15, 2008 I was grinding on a knife yesterday and I noticed a crack. I proceeded to bang the knife against the floor once, which snapped the knife in half. My question is what could've caused this? I did cool it from a black heat, and did straighten it cold some, those are my guesses why. Anyone else have any idea. Also it was made from a HC RR spike Quote Link to comment Share on other sites More sharing options...
Steve Sells Posted June 15, 2008 Share Posted June 15, 2008 something happened. IF you want more detailed answers, we need more detail of the blade, steel type, new/used?, HT, annealed?> forge/stock removal? thickness... it could be many things, but with out knowing, its all wild guesses. forged? Quote Link to comment Share on other sites More sharing options...
LDW Posted June 15, 2008 Share Posted June 15, 2008 I had something similar happen not to long ago and posted a thread. I ended up blaming it on not tempering, and forging at too low a temperature to try and get the hammer marks out. Here is the thread.http://www.iforgeiron.com/forum/f14/should-have-tempered-5211/ Quote Link to comment Share on other sites More sharing options...
Rich Hale Posted June 15, 2008 Share Posted June 15, 2008 Hollon a wild guess is that it was not tempered, those spikes are not high enough carbon to make aknife from but if you were to harden in water from a non magnetic heat and then not temper at all you might have a problem such as yours.There is really a lot to this knife business that relates to basic blacksmithing skills. I am not sure what your back ground is so forgive me if that seems like a slight. Give us a bit more info and maybe we can help more. Quote Link to comment Share on other sites More sharing options...
Hollon Posted June 15, 2008 Author Share Posted June 15, 2008 The steel was a HC railroad spike, it was forged, but had not been heat treated yet. As I said though, I did cool it in water from a black heat, but I didn't think this would harden it enough to cause cracks. I did not anneal before forging as I thought it would be unnecessary. If you have other questions, ask them, and I will answer. Quote Link to comment Share on other sites More sharing options...
Steve Sells Posted June 15, 2008 Share Posted June 15, 2008 annealing is done after forging to relieve stress. when heated to forging temps it erases most of anything that was done before. Old spikes may have stress fractures in there already, New won't have them. sharp angles, areas of drastic transition of thickness, are stress risers in themselves. so dont use a 90 degree inside corner, rather a small rounding at the intersection to avoid this problem. hammering too cold. Most steels have a temperature range they are happy to be forged in, and a range that they are very "annoyed" in IF hammered at black heat it can crack from that.. Please don't give up, keep trying. Used materials have their own problems that cant be avoided. only worked around Quote Link to comment Share on other sites More sharing options...
Dodge Posted June 16, 2008 Share Posted June 16, 2008 "Just when I finally figure out where its at, somebody moves it!!"** LOL I am confused. I thought "normalizing" after forging was to relieve stress. What is the difference between normalizing and annealing? ** quote from Ziggy Quote Link to comment Share on other sites More sharing options...
son_of_bluegrass Posted June 16, 2008 Share Posted June 16, 2008 Depending on how much ambient light there was, the "black heat" may have been above critical. When I forge in full sunlight, non-magnetic is still well below any hint of glowing. ron Quote Link to comment Share on other sites More sharing options...
Steve Sells Posted June 16, 2008 Share Posted June 16, 2008 ok Normalizing is to relieve stress. Annealing does that PLUS softens the steel a lot more. to allow easier shaping cold, ir grinding, filing, sanding,, I better pay more attention to the words I chose. Sorry for any confusion my pea brain caused.. Quote Link to comment Share on other sites More sharing options...
Dodge Posted June 19, 2008 Share Posted June 19, 2008 LOL, Steve, No prob! I wasn't trying to put you on the spot I'm still a newbie as far as metallurgy goes and I'm better edjumakated now and the difference is finally clear in my mind. Makes perfect sense. Thanks, Scott :) Quote Link to comment Share on other sites More sharing options...
Askdamice Posted June 25, 2008 Share Posted June 25, 2008 Dodge, Being fairly green (or shiney, as it were... lol) I'm not up on all the lingo... but I'm pretty sure that the only difference between annealing and normalizing is the cooldown duration. When I normalize after forging (prior to heat treat) I simply lay the red pc on the bricks to let the colour fade out (3 times minimum) and when I anneal, so I can work the steel with tools, I shut the forge down an close it up with the pc inside to cool VERY slowly. I'm not sure what the cooling rate is to achieve good tooling properties... so i may be a little overkill on the annealing. Rick Ps. How is that anvil comming along, bro? Quote Link to comment Share on other sites More sharing options...
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