[TheForge] Do you know if the normalizing differ substantially from the annealing

[Paul Novorolsky]

Awesome information. Thanks Mike. This is the kind of stuff I was 
looking for. I'll have to see if I can find that book, or one similar 
for a reasonable price. (I know current versions of Engineers Handbooks 
are quite expensive.)

Since it doesn't specify a soak time under Normalizing, can I assume 
more than a thorough heating through,that it isn't important here? (with 
a couple statements out of context, I don't want to make any bad 
assumptions...)

Not soaking 1hr/inch would then make multiple normalization cycles make 
a little more sense to me.

**Paul

On 6/5/2013 12:43 AM, Mike Spencer wrote:
>
> George Dixon wrote:
>
>> Do you know if the normalizing differ substantially from the
>> annealing
>>
>> Normalizing is using heat in a controlled manner to remove stress
>> imposed by forging
>>
>> Annealing is using heat in a controlled manner to remove hardness,
>> either from work hardening or heat treating
>
>
> I recall once mentioning "annealing" something by heating it and
> letting it cool in air to Sam Allen.  He corrected me, saying, "That's
> normalizing."  Since Sam is a metallurgy professor at MIT, I reckoned
> I hadda do some reading before I pontificated again. :-)
>
> Looking at Mechanical Engineer's Handbook (Theodore Baumeister,
> ed.,1958), I see that "annealing" is treated as a broad category of
> processes used:
>
>     (1) to remove stresses; (2) to induce softening; (3) to alter
>     ductility,toughness, electrical, magnetic or other physical
>     properties; (4) to refine the crystaline structure; (5) to remove
>     gasses; or (6) to produce a definite microstructure....
>
> Within that category are "fuel annealing" and "normalizing".
>
>      Fuel annealing:
>
>      Heating iron-base alloys above the critical range, holding above
>      that range for a proper period of time, followed by slow cooling
>      below that range. The annealing temperature is generally about 100
>      F above the upper limit of the critical temperature range, and the
>      time of holding is usually not less than 1 hr for each inch of
>      section of the heaviest object being treated.  The objects being
>      treated are ordinarily allowed to cool slowly in the furnace. They
>      may, however, be removed from the furnace and cooled in some
>      medium that will prolong the time of cooling AS COMPARED WITH
>      UNRESTRICTED COOLING IN THE AIR. [Emphasis mine]
>
>      Normalizing:
>
>      Heating iron-base alloys to approximately 100 F above the critical
>      temperature range followed by cooling to below that range in still
>      air at ordinary temperatures.
>
> Other sub-topics mentioned under the general rubric of annealing:
> Process Annealing; Patenting; Spheroidizing.
>
> I once made a (finger) ring by pattern-welding a piece of
> off-the-shelf mild steel with a piece of Volkswagen beetle front
> torsion spring.  Let it cool in air.  File glided off as if it were
> glass.  Re-heated, allowed to cool more slowly in forge cinders. Still
> like glass.  I finally threw it into my kitchen range where it
> remained red hot all evening. I left it there over night so that it
> cooled in the coals (later, the ashes) of a dying fire. Stove was cold
> in the morning. Retrieved from the ashes, the ring could be filed
> fairly easily, albeit noticably harder than mild steel.
>
> So in the first two tries, I was normalizing it (consistent with Sam's
> remark) and in the stove I was "fuel annealing" it, with a long hold
> above critical followed by very slow and even cooling.
>
> VW front torsion bars are, BTW, cool material.  They're compound units
> of ca. 1/8" x 3/4" and 1/8" x 3/8" flat strips roughly a yard long.
> You can clamp the end of one in the vise, bend it over 180 degrees and
> (keeping your head well out of the way!) release it. Just whips back and
> forth.  Heat one end to red, cool in air and try the same thing.
> Snaps off as easily as, say, breaking a candy cane or a thin strip of
> glass.
>
>
> FWIW,
> - Mike
>