Need help with straightening twisted AEB-L steel

Some bad advice in here.

We don't anneal air hardening steels without forging/rolling first to avoid massive grain growth.
 
Check out this post. Good info on a sub critical anneal that should allow you to straighten the blade before re-heat treating.

1350F for 4 hours should do the trick.

K

Thread 'AEB-L Sub-Critical Anneal??'

Hello all, perhaps I should say Hoss or Larrin. I HT'd a 9" slicer type blade of AEB-L with .096" thick, with nice taper from ricasso to tip of .040" using SGA (that SGA sure does work nice). I used the 2 step method given by Hoss. Allow oven to stabilize at 1725F, put blade in oven allow to soak for 20 minutes, plate quench. Ramp oven to 1975F, put blade in oven, allow time for oven to return to 1975F, then soak for 8 minutes, plate quench. Blade came out of plates nice 'n straight. Placed vertically in dry ice slurry for 20 minutes, blade came out with a nice curve in the last 3"...
 
Not a recommendation, just what I do. I get 14C28N always bent as it's coiled for transport.
1. normalizing heat up, clamp with steel angle profiles to straight and cool
2. another normalizing step to recrystallize while straight
3. quenching in oil to 400°C to 450°C and clamp for straightness
Always straight!
 
DeadboxHero said:
Some bad advice in here.

We don't anneal air hardening steels without forging/rolling first to avoid massive grain growth.
Click to expand...
Still confused by this statement Shawn.

Looking at the Good Doctor's book, Knife Engineering, on page 232 is a section titled Recomneded Annealing Procedures.

Larrin says " The temper anneal in high alloy steels provides an array of fine carbides with sufficient stability to survive to the high austenitizing temperatures required in hardening which leads to a finer grain size and carbide size."

 
Cypress Creek Knives said:
many of us are using carbide hammers to straighten our blanks after heat treat. They aren't cheap but they work great!

You can get away with using a carbide tipped masonry bit and hammer.

Here is a video by K H Daily knives explaining how the process works. Good luck!
Click to expand...
Thanks! My dad and I made a carbide hammer for about $20. It has saved me many times. The problem I'm having with this steel is that it's not just warped, but twisted so it's really hard to even get anywhere straight. It seems like I just over pound and it sets it off on the other side!
 
Seedy Lot said:
I run a stress releiving step on all steels now and have very little warp issues. Did a batch of 50 AEB-L and only had to use carbide hammer on one of them. This is with all thinner stock and bevels unground.

I don't know how to straighten twists.
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That's good to know. Do you have a specific recipe for the stress relieving steps you take?
 
Ken H> said:
Yep, twists are the problem it sounds like. Only thing I could think of would be to soak at 1750°F (maybe even more?) then clamp tight between 1" aluminum plates in a vise. You've already tried that and it didn't work so I don't know. Twists are hard - simple bends are simple {g}.

BTW, that video linked above is a very good video on using a carbide hammer.
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Yeah, twists are much harder than warps. I can't seem to find a way to get it all straight. I'll watch the video!
 
Taz said:
Straightening hammers are super easy to make. 3/8" carbide ball bearing, use a glass spade drill bit to drill into the hammer head. Or take a carbide drill bit, drill into the hammer head, smack the flutes off and regrind the end of the knife into the shape you want (round it out or do an oval) and stick it into the hole it drilled into the hammer head.
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Yeah my dad and I made one about a year ago and it has helped me out a lot!
 
Cypress Creek Knives said:
Looks like i didn't read the original post thoroughly enough. I missed the part about OP using a carbide hammer already. I have used my carbine hammer to successfully remove warps and minor twists. Twists are a bit trickier than warps, but the prices is essentially the same.

If the twists are more severe you could surface grind them out, but you will lose a lot of your stock thickness.

I would anneal the steel, straighten, stress relieve, austenitize, then quench. It don't have a good anneal process for AEBL but I'm sure someone does
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I might just keep working it with my hammer and see if I can get it straightened enough. I wish I had a surface grinder!
 
Cypress Creek Knives said:
Check out this post. Good info on a sub critical anneal that should allow you to straighten the blade before re-heat treating.

1350F for 4 hours should do the trick.

K

Thread 'AEB-L Sub-Critical Anneal??'

Hello all, perhaps I should say Hoss or Larrin. I HT'd a 9" slicer type blade of AEB-L with .096" thick, with nice taper from ricasso to tip of .040" using SGA (that SGA sure does work nice). I used the 2 step method given by Hoss. Allow oven to stabilize at 1725F, put blade in oven allow to soak for 20 minutes, plate quench. Ramp oven to 1975F, put blade in oven, allow time for oven to return to 1975F, then soak for 8 minutes, plate quench. Blade came out of plates nice 'n straight. Placed vertically in dry ice slurry for 20 minutes, blade came out with a nice curve in the last 3"...
Click to expand...
Great! I'll bookmark it for reading later. I appreciate it.
 
Keanen said:
That's good to know. Do you have a specific recipe for the stress relieving steps you take?
Click to expand...
I ramp at 500°F to 1200°F and then soak for 2 hours with an oven cool. I do cover the blanks with a foil blanket so the blanks are not exposed to direct radiant heat from the oven coils.
 
a twist requires you to identify and find the ridgeline to straighten it
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