[TheForge] 4140 vs 4340

Thu Apr 4 09:49:03 2002

Shannell:

For 38mm (1-1/2") 4140 bar, welded (SMAW) with low hydrogen electrode, the
recommended preheat temperature is 600 degrees Fahrenheit. A maximum
interpass temperature of 700 degrees is also recommended. In other words,
make sure the part is between 600 and 700 degrees when you strike the arc.

You stated that the bar is already heat treated (presumably quenched and
tempered) but didn't provide specifics. In the event the bar subject the
bar, during welding, to a temperature higher than that at which it was
tempered, you'll soften the bar somewhat. The following is a (very) rough
guide to hardness versus tempering temperature.

600 F - 47 Rc
700 F - 44 Rc
800 F - 39 Rc
900 F - 35 Rc
1000 F - 29 Rc

Hope this helps,
Dan

-----Original Message-----
From: [email protected]
[mailto:[email protected]]On Behalf Of Shannell
Sent: Thursday, April 04, 2002 8:25 AM
To: [email protected]
Subject: Re: [TheForge] 4140 vs 4340

Well I just bought some 4140 after reading this discussion, its for my air
hammer dies. The bar I bought is 38mm square and Im just going to grind it a
little then weld it to the die plate, this bar is already heat treated and
tempered by manufacturer, my question is welding it, does this stuff weld
ok? Id like to keep the factory heat treatment intact so am not sure about
preheat etc, I was going to use 7018 rod.

----- Original Message -----
From: "Dave Brown" <[email protected]>
To: "TheForge" <[email protected]>
Sent: Wednesday, March 27, 2002 7:18 AM
Subject: [TheForge] 4140 vs 4340

> In a recent thread 4340 was mentioned as good die material.  Does anyone
> have an opinion about 4140 for this same application?  Why?  I can get
this
> easier than I can get 4340.
>
> Dave Brown
> Heritage Smithing
> Green Bay, WI
> ABANA, UMBA, GoM, MODA, ARG
>
> _______________________________________________
> http://mailman.qth.net/mailman/listinfo/theforge
> theforge mail list group photo site is
> http://www.photoaccess.com
> Login:  [email protected]
> password:  anvil
> ___________
>
>
>

_______________________________________________
http://mailman.qth.net/mailman/listinfo/theforge
theforge mail list group photo site is
http://www.photoaccess.com
Login:  [email protected]
password:  anvil
___________