Need a book? Engineering books recommendations...

Return to index: [Subject] [Thread] [Date] [Author]

Re: [Fwd: Welding Electrodes]

[Subject Prev][Subject Next][Thread Prev][Thread Next]
ASTM A36 (the material specification) has a lower limit (36 ksi) but no 
upper limit on yield strength. Over the past ten years, wide-flange steel 
producers had taken to targeting their production for the area of overlap 
between all of the tensile and mechanical requirements for A36 and A572 
grade 50. The resulting product was then dual-certified to reflect that 
it met all requirements for both A36 and A572 grade 50.

Although some overstrength in A36 was almost always present, the advent 
of the practice of dual-certification meant that it was at least on the 
order of the ratio of 50 to 36. This can obviously be a problem when the 
optimistic assumption is made that A36 yields at 36 ksi in a seismic 
frame. So technically, ASTM A36 steel is still "available", but probably 
with a significantly higher yield strength than the specified minimum 
value of 36 ksi in wide-flange shapes.

The above comments apply to wide-flange shapes only, not to plate 
products, angles or channels.

To provide a wide-flange product that is more predictable, particularly 
in seismic applications, AISC began several years ago to develop a grade 
of steel that is now all but blessed with an ASTM number. Today, you can 
order it as ASTM A572 grade 50 with special requirements per AISC 
Technical Bulletin #3 (read about it more on the AISC web site 
(www.aisc.org). It's essentially a 50 ksi steel with a maximum yield 
strength of 65 ksi, minimum tensile strength of 65 ksi and maximum yield 
to tensile ratio of 0.85. It also has chemical composition limits that 
make it inherently weldable. I strongly recommend that you all update 
your project specs to call for this steel in wide-flange shapes, 
particularly those that are intended to be the ductile elements of your 
seismic frames. Also, watch for the official ASTM number to be announced 
in the near future.

Charlie

Y. Henry Huang wrote:
> 
> Your comments?
> 
>     ---------------------------------------------------------------
> 
> Subject: RE: Welding Electrodes
> Date: Thu, 20 Aug 1998 10:26:32 -0700
> From: "Bill Allen, S.E." <bill(--nospam--at)allendesigns.com>
> Reply-To: seaint(--nospam--at)seaint.org
> To: <seaint(--nospam--at)seaint.org>
> 
> No A-36? This is a real shock (to me, anyway). The 9th ed. of the AISC
> manual lists A-36 as an available material for just about everything except
> for plates and bars over 8".
> 
> Can you please clarify?
> 
> Regards,
> Bill Allen
> 
> -----Original Message-----
> From: Y. Henry Huang [mailto:hhuang(--nospam--at)co.la.ca.us]
> Sent: Thursday, August 20, 1998 10:25 AM
> To: seaint(--nospam--at)seaint.org
> Cc: AISC - Charlie Carter
> Subject: Re: Welding Electrodes
> 
> <snip>
> There is no such thing as A36 rolled shapes any more.
> <snip>
> Y. Henry Huang
>