Hey fellows,

   So I cycled three times and then quenched this 1084 blade in canola oil today and it bent.. not in the typical direction.. at least not for me.  The blade is triangular in cross section and 20 1/4" overall.  I expect some warping down the spine on occasion but I've never had one bend toward the cutting edge before.  Can anyone give me some advice on what I did wrong.. or a way to avoid this? 

 

It is quite normal for a blade to saber with a nose dive if quenched into oil. it can be a hard thing to predict though. I often harde sword blades in rectangular section and then grind in the bevel after HT. or pre curve the blade a little to take acount of the nose dive.

I have managed to get saber out by holding the blade edge down in two vices and aplying pressure with a fly press, all of this done at Tempering temperature, I would not advise it though its literaly a make or break fix.

The only easy way to deal with it is to grind the blade straight.

What Basher said.  Also may mean you got differential hardening, with the edge hardening and the back of the blade not, or only partially hardening.  You get sabering when you clay coat a Japanese style blade and quench into oil rather than water.  (Maybe someone's figured this out, but I've never heard a great explanation of the physics of why a blade bends in either direction when quenched into water or oil.) 

I know one bladesmith who makes Japanese style blades and quenches into oil, and he deals with this phenomenon by forging an exaggerated curve into the blade before heat treating, so that the sabering has the effect of taking some of the curve out and leaving the blade in a shape he's happy with.  Suspect it takes a fair amount of experience to be able to predict how much curve to forge in and how much sabering will occur so that you get what you want at the end of the process.

If you have a symmetrical cross section and shape *how* it is inserted in the quenchant can also make a difference: a Vertical plunge being less likely to case sabering than a "slice"   Also making sure the blade is evenly heated---edges tend to heat faster than thicker section which can cause issues too.

Thanks fellows. I quenched vertically. After thinking on it a while I don't think it had a choice. The geometry in cross section was so aggressive that the edge must have contracted much faster. I'm a bit surprised there aren't any cracks seeing the warp. Much appreciation again!