Forging-'Lets get this staight'

[hyfan]

Hi Guys, This may be one for British blades but hey maybe theres some joint forum members who can answer?
Ever forged 5160 then you find after normalising that the blade -yo ho has bent slightly . (i.e. its length thro blade to tang has gone off straight edge line.

Now what to do ?theres the dilemma. Does one heat a portion of the blade to none magnetic around the position to be straightened and then correct in the vice between two and one upright rods.Let it cool to room temp in air. Then heat again to none magnetic and let it cool slowly to re-normalise. The worry for me here is that if one does not reheat before straihtening and you do it cold, it will most likely distort on the hardening and quench cycle?

Also posibly this localised heating of the blade might cause more problems?(is it better to reheat the whole blade up?-which is a real pain if your forge is stone cold.)
Any experience with a proven safe method of staightening would be of great help!
Cheers Ivan

 

[firemaker]

Hi hyfan Blade warps are a pain! Check your blade over for thickness you my have high and low spots that are heating up and cooling at different speeds you my also still have some hammered in stress left , I would heat it up slowly to non magnetic check with a magnet if it does not stick hould it at that temp for a few minutes then take it out and use a wood hammer or heavy stick to straighten the blade this can also be a pain and a half!!! Also are you quenching in oil (not water)? Have you tryed just quenching the edge and not the hole blade? also it may be that your blade is to thin for its length. I work with 5160 for most all that I make. When you do have it where you want it bring the blade back to non mag hould it there the same as before the thing you want is an even heat the hole length of the blade just at non mag then have your quench tank close and dont move side to side with the blade in the tank that can cause a warp. also face the point duwe north when you quench. I hope this helps I'm sure there are others with some advice also.

 

[ESpy]

Depending on the blade, I'd straighten it cold then re-anneal. Nice and slow in the varmiculite box, possibly with a large lump of steel at red heat to keep it company.

I'd be looking for uneven heating in the normalising cycle too!

 

[hyfan]

I am quenching in hot vegetable oil.Good advise about using the none compacting wooden hammer,The blade is 5.5 inches so I WILL HAVE TO FIRE UP THE FORGE TO GET AN EVEN HEAT PRIOR TO QUENCH.
Thanks for the advise guys-Cheers Ivan

 

[ESpy]

This month's Blade has an article on warping... Biggest culprits listed were uneven heating and uneven forging.

Normalise, normalise, normalise!

(OK, so I don't triple normalise in the demos, it takes too long!)

 

[Lord Farquhar]

What kind of blade ?
A scandi tang or a fuller?

5160 is tough steel so it’s not easy to crack
As you are forging use smaller hammers and lighter blows the closer you get to completion of the blade and normalize a few times to ease internal pressures in the steel.