[TheForge] A36 vs 1018

Wed Feb 11 19:11:28 EST 2009

Thanks for the voice of experience. I guess when I see a spec like the 
ones I cited and expect the "typical" values to be, well, typical.

I suppose I could spring for the $32 and order the ASTM  A36 spec, but 
I'm not sure that will really tell me anything. Maybe I'll have to swing 
by the library and see if I can find it there.

I've been stubbornly trying to find a way to reliably weld the A36, 
maybe that's a bad choice. I figure I've "enough" success with it to 
make me think this can be done, and perhaps I was determined that I can 
find a way around my failures. But with little more than empirical 
experience, I'm probably setting myself up for a lot of frustration.

As you noted, the cost of 1018 has me hoping that I could make A36 work. 
Since I'm not in production, my time at this isn't all that valuable (in 
terms of $$) but it may be time to give up on A36, and stop wasting time 
on it.

**pn

David Childress wrote:
> In our group there is much debate about A-36.  I know from job
> experience ( engineer in a tool & die shop) something about a36.  The
> fact is that A36 is made from scrap and is junk.  Most of the specs
> are max without min. or min. without max. and there are many metals
> that are not mentioned  at all that may or may not be present.  Our
> forgemaster really dislikes A36, but when a found a a distributor that
> was willing to sell 1018 to us at his cost the cost still freaked most
> of us out ( about 185% of A36 cost).
>
> I have been told that the lead and copper in A36 is what makes it hard
> to forgeweld.  These are allowed for ease of machining, but due to the
> processing of A36 they are not necessarily evenly distributed.  So
> some places will forge weld and maybe 6" down the bar it will not weld
> at all.
>
> I had a diemaker  tell me that once they got a piece of A36 that he
> could not drill a hole thru.  some other Die maker cut the peice up
> and found a piece of coil spring that had never melted at the end of
> the attempted hole.  As another example my daughter made her first
> knife ( letter opener) out of A36.  Being impatent as she always is (
> 13 yrs old)  when she got it shaped she threw it in the quench tank.
> We could not sharpen it (Hrc 68).
> A36 is just like that.  It is good enough for most structural uses,
> but you can never tell what it will be like.
>
> David Childress
> Rocky Forge Blacksmith Guild
>
> On 2/11/09, Paul N <crosspein at sbcglobal.net> wrote:
>   
>> OK, I've been reading that PDF that Frosty posted a couple weeks ago,
>> and I'm about halfway through my first pass at it. (It will likely
>> require more than 1 to understand it)
>>  (It was this one: http://www.feine-klingen.de/PDFs/verhoeven.pdf)  And
>> many thanks for posting that. It's just the kind of description I had
>> been looking for.
>>
>> We should probably start "Frosty's Book Club" discussions, as I'm sure
>> that there are things I think I understand, but that I've
>> mis-interpreted. But that's a different story.
>>
>> I'm finding the "book" very enlightening, and not horribly difficult to
>> read. (Although anything even approaching an hour at a time seems to
>> stimulate the auto-nap response) I had taken a metallurgy class in
>> college over 30 years ago, but studying to pass a class is totally
>> different from studying to LEARN. So while I've been exposed to this
>> stuff before, this time is different and enlightening.
>>
>> OK, now for my real question:
>>
>> I've occasionally been stymied while trying to forge weld with hot
>> rolled A-36 steel, and since it occurred last night while I was
>> demonstrating how to make a basket handle (using 6 pcs of 1/4" round
>> A36) I thought maybe it's time to ask. I've made dozens of these, so
>> it's not exactly a new process for me.
>>
>> My problem last night was that the person that asked for the demo had a
>> pretty hollow (coal) fire, but I thought that I'm finally getting pretty
>> good at this, so why not go ahead with it as is. The first weld, with
>> all the pieces kind of loose, went off without a hitch. Welded nicely on
>> the step of the anvil. But when I went to the other side, which I've
>> always found easier as it's more stable, it didn't take. That's not
>> really a problem in itself. I've been here plenty of times.
>>
>> What became an issue is, now even after correcting the fire, I can't get
>> it to weld. After about 4 attempts, the ends are now hopelessly
>> distorted and difficult to repair and I abandoned my demo in
>> frustration. BTW, I was using straight 20-mule team borax as a flux.
>>
>> So, what happens to the metal? Does it pick up contaminants? Did it
>> de-carburize (there was a little sparking, but not what I'd consider
>> significant, and even if it did, wouldn't the lower carbon level make it
>> easier to weld? )
>>
>> In the past, when I've had a failure like this with A-36, Usually end up
>> cutting back the ends to get a successful weld, so I'm expecting that
>> there has been some metallurgical transformation here. So I'm wondering
>> if anyone knows what that change might be.
>>
>> Since I'm feeling a little more knowledgeable now, I've looked at  the
>> chemical compositions of 1018 and A-36, and aside from the slightly
>> higher carbon content of A-36 (about 0.25% C vs 0.18% C) there isn't all
>> that much difference, chemically. Perhaps it's the inherent grain size,
>> and with a little annealing the A-36 would behave better?
>>
>> (Using references from:
>> http://www.benjaminsteel.com/Technical%20Data/A-36-properties.htm and
>> http://www.geocities.com/haimanaua/htdocs/steels/1018.html )
>>
>> So, can anyone explain the differences in behavior in A-36 and 1018 when
>> it comes to forge welding?
>>
>> thanks,
>> **pn
>>
>>
>>
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