Bending annealed HSS?
 

Hi folks,

I've been experimenting with heat treatment and have tried bending annealed HSS, partly out of curiousity.

I've tried annealing and bending blunt drills and hacksaw blades, but with little success. They seem brittle even after bringing them up to an orange-red heat and letting them cool in the air.

Should it be possible to bend annealed HSS? Do I need to bring them up to a higher temperature, cook them for longer or bury them in sand for really slow cooling?

Thanks,

Chris

Bending annealed HSS?
 

On Sun, 1 Mar 2020 11:25:34 -0800 (PST), Christopher Tidy
wrote:

Hi folks,

I've been experimenting with heat treatment and have tried bending annealed HSS, partly out of curiousity.

I've tried annealing and bending blunt drills and hacksaw blades, but with little success. They seem brittle even after bringing them up to an orange-red heat and letting them cool in the air.

Should it be possible to bend annealed HSS? Do I need to bring them up to a higher temperature, cook them for longer or bury them in sand for really slow cooling?

Thanks,

Chris
Bending hot usually works best.
However annealing HSS requires cooling it VERY slowly - minimum 1
hour from cherry red to comfortablle to the touch. Usually done by a
blacksmith by burying it in hot ashes and letting it cool.

Try putting red hot part in 600 degree oven then turn down to 400,
then 300, then shut off over a period of an hour and see what happens.
If you can't easily cut it with a file it's not annealed.

Bending annealed HSS?
 

On Sunday, March 1, 2020 at 11:25:36 AM UTC-8, Christopher Tidy wrote:
Hi folks,

I've been experimenting with heat treatment and have tried bending annealed HSS

The various high-speed steels are hardened in a process that generates hard
(vanadium carbide etc.) crystals in the steel matrix. So, annealing requires heat
and time to dissolve those crystals; it's NOT the steel, but the additives,
that have to be considered. Re-hardening to recreate those crystals can
be a complex process, too.

It's easier to use hardenable steels that haven't ever been hard.

Bending annealed HSS?
 

On Sun, 1 Mar 2020 11:25:34 -0800 (PST), Christopher Tidy
wrote:

Hi folks,

I've been experimenting with heat treatment and have tried bending annealed HSS, partly out of curiousity.

I've tried annealing and bending blunt drills and hacksaw blades, but with little success. They seem brittle even after bringing them up to an orange-red heat and letting them cool in the air.

Should it be possible to bend annealed HSS? Do I need to bring them up to a higher temperature, cook them for longer or bury them in sand for really slow cooling?

Thanks,

Chris

Read:
https://www.hudsontoolsteel.com/technical-data/steelA2

Or simply google "anneal+tool+steel"
--
cheers,

John B.

Bending annealed HSS?
 

Thanks for the responses. Which is more important, the long bake at red heat or the super-slow cooling?

I could put the HSS in a crucible and dial back the power a little each hour using a variac.

Chris

Bending annealed HSS?
 

On Sun, 1 Mar 2020 17:02:42 -0800 (PST), Christopher Tidy
wrote:

Thanks for the responses. Which is more important, the long bake at red heat or the super-slow cooling?

I could put the HSS in a crucible and dial back the power a little each hour using a variac.

Chris

Basically both. The long bake ensures that the "structure" of the
steel is even throughout the steel and the slow cooling ensured that
no "air hardening" for want of a better word, takes place.

I did once anneal a HSS tool bit by heating it for about 8 hours in a
heat treating furnace and than cooling it over about 16 hours in the
oven which had an automatic heat control that was set to reduce the
heat every hour.

But why anneal HSS?
--
cheers,

John B.

Bending annealed HSS?
 

On Sun, 1 Mar 2020 17:02:42 -0800 (PST), Christopher Tidy
wrote:

Thanks for the responses. Which is more important, the long bake at red heat or the super-slow cooling?

I could put the HSS in a crucible and dial back the power a little each hour using a variac.

Chris
It's both - get the piece up to temp through and through, then cool
VERY slowly so the crystals don't form

Bending annealed HSS?
 

"Christopher Tidy" wrote in message
...
Thanks for the responses. Which is more important, the long bake at
red heat or the super-slow cooling?

I could put the HSS in a crucible and dial back the power a little
each hour using a variac.

Chris

https://www.amazon.com/dp/B07KT9RZFJ/ref=dp_cerb_2
There are many choices, this one has a short URL.

Carbon fiber insulation is much more durable and may be easier to find
locally. It conducts electricity so I couldn't use it near the oven's
exposed heater wiring.
https://www.amazon.com/Carbon-Weldin...3149508&sr=8-8

I've used wood stove cement to insulate high temperature
thermocouples.