That steel can get incredibly hard if it gets hot, but the barrels are not very hard at all.

Why pay extra for tool steel?

TIA

On Sat, 23 Feb 2013 13:56:37 -0800 (PST), clark
wrote:

That steel can get incredibly hard if it gets hot, but the barrels are not very hard at all.

I'm not sure what you mean by that; 4140 softens with heat just like
every other steel.

As for gun barrels, 4140 has relatively high tensile strength even
when tempered at high temperatures (for example, temper at 800 deg. F,
and yield strength is still 120,000 psi).

The result is a strong steel that has high elongation (13%, in this
case). That means it's strong but not brittle; its ductility is quite
high for such a strong steel. It's relatively safe with high chamber
pressures.

That makes a good gun barrel. It has good wear resistance, too.


Why pay extra for tool steel?

4140 is not really a tool steel. It's a medium-alloy, medium-carbon
steel. Because it contains chromium and molybdenum, it will harden
with only 0.40% carbon to a higher degree than, say, 1040 steel.

--
Ed Huntress


TIA

clark wrote:

That steel can get incredibly hard if it gets hot, but the barrels are not very hard at all.

Why pay extra for tool steel?



Why indeed? Maybe they looked at the real issues and decided it was
the proper steel, rather than using old galvanized water pipe? Maybe
they don't like a barrel splitting when it fails to contain the pressure
from the rounds, when fired?

On Feb 23, 2:56*pm, clark wrote:
That steel can get incredibly hard if it gets hot, but the barrels are not very hard at all.

Why pay extra for tool steel?

TIA

Don't want HARD, want tough and more important, want a material that
resists erosion from very hot, very high velocity and very high
pressure gas. And what the commercial barrel makers order for steel
isn't 4140 that you get from the local steel merchant. Since they
order tons at a time, they can get an alloy that does the same or
better for physical properties, but is easier to machine and pull
buttons through. If you had a super-hard barrel, it'd probably
grenade, too brittle to take the near-instantaneous pressure load.
Some army officer had the same bright idea, I've got a book that shows
the results of putting case-hardened throats in cannon. Didn't last
more than a few rounds before they shattered. And 4140 is hardly
"tool steel". High chromium and nickel content cuts gas erosion
considerably, back in the early days of smokeless powder, they found
that plain carbon steel barrels that were fine for black powder and
lead bullets just had their rifling go away in a few hundred shots.
Winchester used nickel steel for the first time in their 1894 .30-30
barrels for that reason. A big deal in the late 1890's, using an
alloy steel.

There are a few books out there on barrel making, most are short run
printings, but can be had. I've got a couple.

Stsn

On Feb 24, 1:29*am, Stanley Schaefer wrote:

*And 4140 is hardly
"tool steel". *High chromium and nickel content cuts gas erosion
considerably, back in the early days of smokeless powder, they found
that plain carbon steel barrels that were fine for black powder and
lead bullets just had their rifling go away in a few hundred shots.

Stsn


4140 is what i would call a low alloy steel. Chrome and Moly, but no
Nickel.


SAE grade % Cr % Mo % C * % Mn % P
(max) % S (max) % Si

4140 0.80–1.10 0.15–0.25 0.38–0.43 0.75–1.00 0.035
0.040 0.15–0.35




Dan

On Sat, 23 Feb 2013 22:29:08 -0800 (PST), Stanley Schaefer
wrote:

On Feb 23, 2:56*pm, clark wrote:
That steel can get incredibly hard if it gets hot, but the barrels are not very hard at all.

Why pay extra for tool steel?

TIA

Don't want HARD, want tough and more important, want a material that
resists erosion from very hot, very high velocity and very high
pressure gas. And what the commercial barrel makers order for steel
isn't 4140 that you get from the local steel merchant. Since they
order tons at a time, they can get an alloy that does the same or
better for physical properties, but is easier to machine and pull
buttons through. If you had a super-hard barrel, it'd probably
grenade, too brittle to take the near-instantaneous pressure load.
Some army officer had the same bright idea, I've got a book that shows
the results of putting case-hardened throats in cannon. Didn't last
more than a few rounds before they shattered. And 4140 is hardly
"tool steel". High chromium and nickel content cuts gas erosion
considerably, back in the early days of smokeless powder, they found
that plain carbon steel barrels that were fine for black powder and
lead bullets just had their rifling go away in a few hundred shots.
Winchester used nickel steel for the first time in their 1894 .30-30
barrels for that reason. A big deal in the late 1890's, using an
alloy steel.

There are a few books out there on barrel making, most are short run
printings, but can be had. I've got a couple.

Stsn

I wonder how P-7 would work for gun barrels?


The methodology of the left has always been:

1. Lie
2. Repeat the lie as many times as possible
3. Have as many people repeat the lie as often as possible
4. Eventually, the uninformed believe the lie
5. The lie will then be made into some form oflaw
6. Then everyone must conform to the lie

That maybe related to its bollet material. And maybe the properties of a href="https://steelpurchase.com/4140-scm440-17225-steel/"4140 steel/a after heat treatment can handle that.