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RES: ASTM A36

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Dear Sir

Thanks a lot.

In my original E-mail I said that we have acquire the last edition of the Norm, sowe have already the chemically/mechanically characteristic of the ASTM A 36.

But there are not a indication of minimum contend of carbon. I understand that the strength of material depends upon the carbon contents, so you will have a very different mechanically properties with different contents of carbon. (I assume al other elements are according to the Standard). If ASTM has a yield point of 248 MPa it seems to me that this mean there must be a minimum carbon content to obtain this value.

In the SAE 1020 standard they specified a carbon content of 0,17 -0,23. 

In the German Standard for S275JR, the most similar to ASTM A 36, (DIN 10025) specify  too the maximum and minimum. 

It is not practical if you must verify (test)  all the material you get in order to know what are the mechanical data.

Again thanks a lot for your response.

Best regards      



Mário Velez Nauer
DEMAG CRANES & COMPONENTS LTDA
*Telefone: 00 55 11  2145-7886
*Telefax: (11)   4616-1371
Cotia-SP-Brasil
*e-mail: mario.velez(--nospam--at)demagcranes.com.br
*site: www.demagcranes.com.br



-----Mensagem original-----
De: Christopher Wright [mailto:chrisw(--nospam--at)skypoint.com]
Enviada em: sexta-feira, 3 de fevereiro de 2006 14:28
Para: seaint(--nospam--at)seaint.org
Assunto: Re: ASTM A36



On Feb 3, 2006, at 5:44 AM, Mario Velez Nauer wrote:

> We use in Brazil still a lot of steel plates/beams etc. made according 
> to ASTM A36. 
> What is the admissive minimum Carbon content of this material ?.
One of those questions where you've either said too little or too much.

A-36 has a maximum Carbon content, not a minimum. The maximum varies 
from 0.25% to 0.29% depending on thickness. Thicknesses over 1/4 inch 
also require a manganese content ranging between 0.8 and 1.2% and 
silicon between 0.15 and 0.3%.  And there's a maximum phosphorus and 
sulfur content of 0.04% and 0.05% respectively. There are also some 
very important process and delivery requirements that are in the spec, 
which you should get immediately. This is information that you 
absolutely must have, and if you haven't memorized most of it you're 
going to end up in trouble.

If I were to guess, I'd say someone is trying to tell you that some 
steel is 'just the same' or 'probably' A-36 and you're looking at some 
chemistry to support the claim. You want to be very careful what you do 
with this stuff, particularly if you're going to weld it. If you really 
don't know what you have you need to find out by doing some 
metallurgical testing to find the mechanical properties, microstructure 
and chemistry. If you're going to weld it, you should make welding 
procedure test plates and test those, too.

I'm not criticizing, I'm telling you so you'll know. Just the fact that 
you don't know that the carbon specification is a maximum, not a 
minimum, is a red flag. With cranes especially you're subject to cyclic 
loading and unknown steel welded improperly is a recipe for fatigue 
failures. Get the stuff tested.

If I guessed wrong, I'm sorry for lecturing.

Christopher Wright P.E. |"They couldn't hit an elephant at
chrisw(--nospam--at)skypoint.com   | this distance" (last words of Gen.
.......................................| John Sedgwick, Spotsylvania 
1864)
http://www.skypoint.com/~chrisw/


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