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RE: A7 steel

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Title: RE: A7 steel

Tom & Arvel (and whomever else wants to jump in:

This is a pedestrian truss bridge out in the middle of nowhere.  I’m not even sure its A7 but since I don’t know when it was built and it does have LBP, I’m being conservative in that assumption. We need to add a connection plate near a joint at the end of one of the vertical members.  Low stresses.

Candi

 

-----Original Message-----
From: Arvel L. Williams, P.E. [mailto:awilliams(--nospam--at)gwsquared.com]
Sent: Friday, April 15, 2005 2:26 PM
To: seaint(--nospam--at)seaint.org
Subject: RE: A7 steel

 

Candi,

 

Step away from the Kool-Aid.  You probably can't effectively heat treat A7 in place on the bridge.  I think your big problem will be localized in the HAZ of the weld and depending on the size of the weld a potential fatigue problem.  If you component is fracture critical, as most older bridges are, this could be a real bummer.

 

Think about this, a lot.  The local metal guru can be more eloquent about this welding problem.

 

Arvel

-----Original Message-----
From: Hans E Boge [mailto:Hanseb(--nospam--at)boge-boge.com]
Sent: Friday, April 15, 2005 1:14 PM
To: seaint(--nospam--at)seaint.org
Subject: RE: A7 steel

Our office policy is not to weld to A7 steel for main structural elements. 

Not only is the welding difficult it adversely affects the parent material.

Handrails and light loads from cable trays are permitted on occasion.

I have never seen a welding procedure to a7 steel with modern steels.  Anyone have one.

That being said, I have welded to A7 steels as a last resort, but then I put on lots.  Double what is typically required.

----------------------------

Hans E. Boge, P. Eng.

Boge Boge (1980) Ltd.

268 Ellen Street

Winnipeg MB, Canada, R3A 1A7

p:(204) 942-7276 ext 223

f:(204) 942-7288

www.boge-boge.com

hanseb(--nospam--at)boge-boge.com

-----Original Message-----
From: Candi Anderson [mailto:canderson(--nospam--at)mercadoeng.com]
Sent: Friday, April 15, 2005 1:03 PM
To: seaint(--nospam--at)seaint.org
Subject: A7 steel

I’m past the LBP problem and move on to my next consideration: Can one weld to A7 steel?  I read that the carbon and manganese content can sometimes present welding problems and hence the development of A373 and then A36.  If the connection is too small/tight to accommodate bolting, is welding an option on this material?

Candi Anderson, P.E.

Associate/Chief Engineer

Mercado Consultants, Inc.

17830 New Hampshire Ave.  #200

Ashton, Md 20861

Office: 301-260-0090;  FAX: 301-260-0018