They stayed in the oven at 1550 about an hour. I shut the oven off
and left them in overnight to cool slowly. I did clean the scale off
before testing hardness, but I am still skeptical of it being softer
than 1018. An online source claims 4140 annealed is 12 HRC, so maybe
it is plausible.
I have used carbide to cut hardened steel, but it is not very
enjoyable to do on a Clausing 8520 without coolant. The mill does
not have the girth to support the necessary tool pressure. The risk
of breaking endmills is high. I would rather save my carbide for
when I have no other options.
On 4/28/2024 12:16 AM, mike allen via
groups.io wrote:
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Good deal . How long did ya cook them ?
thanks
animal
On 4/27/24 8:45 PM, Mike Poore wrote:
Just an update in case anyone is interested. I annealed the tool
holders at 1550 F. Before annealing, they tested at 45 HRC.
After annealing, they tested at 8 HRC. I have read I should use
a B scale tester, but I do not have one. A scrap piece of 1018
tested at 15 HRC, so these holders should be easy milling.
On 4/25/2024 11:37 AM, Mike Poore
via groups.io wrote:
I did a search for that number. The indicates that is the
Swedish equivalent to 4340.
Sorry for wasting everyone's time. I hate when people ask
easily answered questions and I am guilty. I found this that lists the HT specs
for most alloys. 1550F is within the annealing range of almost
every alloy on the list. 1500F is within the hardening range
for almost all alloys. I will have to do more research on
tempering, but for an insert holder there should be a wide
tolerance.
On 4/25/2024 1:17 AM, Andrei via
groups.io wrote:
Found a reference online to SS2541 being
used for tool bit holders. Maybe check that.?
The problem is I do not know the alloy. I guess I will
use the 4140 specs.
On 4/25/2024 12:59 AM,
Andrei via groups.io wrote:
That is definitely a great option. I
don't have one so my go-to was carbide and
coolant.youbare in great shape with the oven
I have a heat treating oven right next to my mill,
so I would rather use the oven.
On 4/24/2024 11:02
PM, Andrei via groups.io wrote:
Are short of squirter bottles or
endmills?
Not an option for me.
On 4/24/2024
9:43 PM, Andrei via groups.io wrote:
Use a carbide endmill and
coolant. No need to anneal
Anyone happen to know the alloy most likely
to be used for carbide insert tool holders? My
guess is 4140. I have four that I need to mill
down to work in an AXA holder. They test at 45
HRC. Thinking about annealing them before
milling and then heat treating again, so I
would like specs to use.
