[TheForge] Welding 5160

Tue Aug 26 11:44:01 2003

----- Original Message ----- 
From: "Thomas A. Troszak" <[email protected]>
To: <[email protected]>
Sent: Monday, August 25, 2003 8:05 PM
Subject: Re: Re: Re: Re: Re: Re:[TheForge] Welding 5160


> > From: "gblacksmith" <[email protected]>
> > Subject: Re: Re: [TheForge] Welding 5160
> > Date: Mon, 25 Aug 2003 17:40:37 -0700
>
> > Thomas:  Ditto....the "something happening" you refer to is the
formation of
> > austenite over time, at the critical temperature.  This critical
temperature
> > must be held long enough for this transformation to occur.  Your
> > observations support what is known to  be physical law.  Upon reaching
the
> > austenitic state, elements such as iron, tungsten vanadium and
molybdenum
> > join carbon in solution.
>
>
> Dear Grant,
>
> I have a real question this time. I once poured a casting from zinc, and
> when cut and etched, it was apparent that the grains near the "chilled"
> outer edges were quite small, and the grains near the center were quite
> large, where they had time to grow before (or during) solidification.
>
> Is there a corresponding effect occurring in the tool steel? Will tool
steel
> "as quenched" have smaller grains (and thus greater hardness and
> brittleness), and then do they (the grains) grow again while tempering
(thus
> helping making the steel tougher)?
>
> Am I even close?  Or is grain size not a factor?
>
> Also, It seems to me that the fracturing of larger, tougher grains into
> smaller grains (by mechanical stress) is essentially the mechanism of
"work
> hardening"  Yes, No?  Is a light about to go on in my head, or am I
barking
> up the wrong track here?
>
> I am actually really curious to know, even if I have put my foot in my
> keyboard again...
>
> Tom Troszak
>
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