Chrome Moly shortage

On 04 Dec 2003 20:09:54 GMT, S (Whunicut) wrote:

Actually they are out of 'normaized' condition 4130 plate/sheet.
In the mean time annealed condition is still avaliable. Would an experienced
member please outline procedure for normalizing from annealed back to usable
normalized condition (prior?) to cutting out parts.

Thanks in advance, Lyle


In annealing an alloyed steel, the part is heated to just above the "critical"
(varies according to the alloy, 1550 degrees F rings a bell for 4130)
temerature. Around 50 degrees F above, IIRC, at which point the steel is single
phase austenite. The part is then slowly cooled, austenite is retained, as much
as possible. Steel is then very ductile and easy to work.
To normalize, the steel is first heat treated to the hardened state by, again,
heating to critical temperature but this time quenching in the proper medium
for that particular alloy. 4130, I think, can be either oil quenched or air
quenched. The steel is then tempered or "drawn" to the correct R "c" scale for
normalizing.
Some steels do not require the tempering step in the normalizing process and
can be cooled in still air from the critical temperature and be ready to go.
So...make your parts from the annealed material. It will work easier, bend
using a much smaller radius without cracking and be easier on your drill bits.
Take the parts to a commercial heat-treater and tell them you want the parts
normalized. Specify "no scale" and they will come back shiny and bright from
being heat-treated in a vacuum furnace or take them to a Tool&Die shop who will
probably heat treat them for free if you dont mind waiting until they have a
load to go into their furnace. To prevent scale, they will wrap the parts in SS
foil before placing in oven.

Regards,
Warren

I must admit to not understanding his question. In Australia
normalised and annealed mean the same thing.
Stealth Pilot

I don't know about
"Stealth Pilot" wrote in message
...
On 04 Dec 2003 20:09:54 GMT, S (Whunicut) wrote:
I must admit to not understanding his question. In Australia
normalised and annealed mean the same thing.
Stealth Pilot

Sorry, hit the wrong button. I don't know about 4130 specifically.
However, when I worked in a metal fabrication shop, normalizing and
annealing were similar, but not the same. Annealing was when the steel was
heated to above the critical point and VERY SLOWLY cooled. That means that
it was wrapped in insulation or buried in hot ashes, or anything to increase
the cooling time. A minimum of 2 hours and as much as 12 hours were spent
on cooling.

Normalizing was heating the steel to above the critical point, but letting
it air-cool in still air. This would mean a cooling time of 15 minutes to
45 minutes. In no case was the hot steel dipped in oil or anything else (as
was mentioned in an earlier post). That is quenching, a completely
different process.

In other words, normalizing is careless (or incomplete) annealing. It is
soft, but not as soft as annealed steel. It is ductile, but not as ductile
as annealed steel. It has more internal stresses than annealed steel.
However, it is MUCH quicker, which is important in manufacturing.

"Harry O" wrote in message
...
I don't know about
"Stealth Pilot" wrote in message
...
On 04 Dec 2003 20:09:54 GMT, S (Whunicut) wrote:
I must admit to not understanding his question. In Australia
normalised and annealed mean the same thing.
Stealth Pilot

Sorry, hit the wrong button. I don't know about 4130 specifically.
However, when I worked in a metal fabrication shop, normalizing and
annealing were similar, but not the same. Annealing was when the steel was
heated to above the critical point and VERY SLOWLY cooled. That means that
it was wrapped in insulation or buried in hot ashes, or anything to increase
the cooling time. A minimum of 2 hours and as much as 12 hours were spent
on cooling.

Normalizing was heating the steel to above the critical point, but letting
it air-cool in still air. This would mean a cooling time of 15 minutes to
45 minutes. In no case was the hot steel dipped in oil or anything else (as
was mentioned in an earlier post). That is quenching, a completely
different process.

In other words, normalizing is careless (or incomplete) annealing. It is
soft, but not as soft as annealed steel. It is ductile, but not as ductile
as annealed steel. It has more internal stresses than annealed steel.
However, it is MUCH quicker, which is important in manufacturing.

"Harry O" wrote in message
...
I don't know about
"Stealth Pilot" wrote in message
...
On 04 Dec 2003 20:09:54 GMT, S (Whunicut) wrote:
I must admit to not understanding his question. In Australia
normalised and annealed mean the same thing.
Stealth Pilot

Normalizing was heating the steel to snipped
above the critical point, but letting
it air-cool in still air. This would mean a cooling time of 15 minutes to
45 minutes. In no case was the hot steel dipped in oil or anything else (as
was mentioned in an earlier post). That is quenching, a completely
different process.
snipped
You`r right Harry O. I was thinking of when we would draw tool steel down to a
normalized R "c" reading in the draw furnace and try to avoid hard spots. i.e.
mold steels etc.
Thanks for the correction.

Warren