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[Fwd: Grade 50 Steel]

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Michael Cochran's post responded by Mike Engestrom of Nucor-Yamato
steel:
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In a message dated 11/9/98 3:32:53 PM Eastern Standard Time,
hhuang(--nospam--at)co.la.ca.us writes:

<< My understanding is that all structural shapes produced today in the U.S.
for ASTM A36 and A572 Grade 50 are made from scrap steel.  Since it is made
from scrap, the minimum yield typically for all shapes ( including angle,
channels, WT's, etc) is greater than 50 ksi eventhough these other shapes are
still referred to being ASTM A36.   For design of lateral force resisting
elements (braced frames, etc.) where shapes other than wide flanges may be
used, should the designer be considering that the actual steel yield for
channels, angles, etc is at least 50 ksi eventhough they would be specifing
A36 for the material.  I understand that a new proposed ASTM A992 is being
developed for the wide flange sections only.  Is it intended that angles,
channels, etc will be included within this specification in the future.  I
don't know if NYS produces tube sections, but what would be the reasonable
expected yield of these members.  From the mill certs for rectangular tubes
(ASTM A500, Grade B, Fy=46 ksi) I have seen yield values ranging from 52 ksi
to 64 ksi with the average aroung 57-58 ksi.  I would assume for seismic
lateral design purposes (tension) that I should be using an average yield
strength of 57 ksi instead of 46 ksi.  Thanks, Michael Cochran, Brian L.
Cochran Associates, Los Angeles, CA >>

Henry,

This is in response to the message from Michael Cochran you forwarded to me.
I could not determine Michael Cochran's email address from the basic message
so I hope you will forward my response to him.  

All domestic USA production of wide flange structural steel shapes is from
scrap-based electric arc furnace, continuous cast mill operations.  ASTM
recently approved a new grade specification for W-shape sections which we
believe will be called ASTM A992 (this is expected to become official by ASTM
within the next few months when they publish the new spec).  

Non-W-shape sections, and W-shapes for that matter, will still be available
via ASTM A36 and ASTM A572 Grade 50.  The properties of structural angles and
channels were not surveyed like those of W-shapes over recent years, so it may
not be prudent to assume that the majority of these smaller shapes are in the
Grade 50 category.  WT's ("split T's") are simply W-shapes split down the
middle of the web forming the T-section, so the properties conform to the
original W-section.  The vast majority of angles and channels are produced by
"bar mills".  NYS only produces a selected range of channel and angle shapes
and are typically a large section size compared to the product size from the
bar mills.  At the current time, only W-shapes are intended for use with the
new ASTM A992 spec.  

I believe AISC has made recommendations on what grade to use for the detail
material (angles, channels, plate), so I will forward this message to them for
their response.

Nucor-Yamato Steel does not produce HSS (structural tube sections).  Maybe
AISC can respond to the questions concerning HSS.  

Mike Engestrom
Technical Marketing Director
Nucor-Yamato Steel
(301) 694-3067
(301) 694-2349

copy:  Nestor Iwankiw, AISC

P.S.:  Henry, I noticed you are spelling my name incorrectly within the
parentheses, however, you are obviously using the correct email address.  My
last name is correctly spelled:  Engestrom.  Be careful on this because there
is another email addressee with the name "Engstrom" on AOL, and sometimes that
person gets my messages by mistake.  


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