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RE: B sections

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Matt,

There are 2 distinct "B" Sections.  

The B sections in the original inquiry were Bethlehem B 20x59, date back to
the 1920's, and were made from ASTM A-9 steel.  If it is a B section and if
it is 20" deep, it is the old Bethlehem beam.  In the beginning of steel,
the players were Jones & Laughlan, Carnegie, and Bethlehem.

The B sections you are referring to are light beams, also called
miscellaneous beams.  The deepest of these sections is 12".  These sections
were generally constructed of A7 steel, but could be A9 or even A36.

The A-36 steels did not dominate the market until the late 1950's and early
1960's.

In the early days of structural steel, the connections were made with
rivets.  Structural steel welding was not a big issue until World War II
where shielded metal arc welding became common, and came from the ship
building industry.  The carbon and/or carbon equivalent contents were
lowered by steel manufacturers to facilitate welding during the reign of A7
steel.  But the real push to formally lower the carbon equivalents and
facilitate welding came with the A36 steels.

If it is an A9 steel, you have only a slight chance of it being easily
welded.
If it is an A7 steel, your chances are 50 / 50 even on the same beam.  The
material quality was highly variable.  Carbon lenses were the rule.  Your
odds improved with late 50's to early 60's A7 steel, but were a long shot on
A7 steel of the 1930's.
If it is an A36 steel, it is weldable.

Summary:
For A9 steel, have the contractor get a mag drill.  
For A7 steel, determine the vintage, test the hell out of it with a good
metallurgist, get good welders, count on preheat, inspect 100% of all welds,
and carry a rabbit's foot, 4 leaf clover, etc.
For A36 steels, relax and make sparks.

You won't find most of this stuff rit down nowhere.  It is just what I have
picked up along the way, doing tons of rehabilitation, watching welds crack,
scratching my head, and listening to old guys espouse wisdom.  I have a low
threshold of pucker factor, and a decent rememberer.

Regards,
Harold Sprague


> -----Original Message-----
> From:	Matthew Jordan [SMTP:MattJ(--nospam--at)CRJARCH.com]
> Sent:	Wednesday, March 08, 2000 1:06 PM
> To:	'seaint(--nospam--at)seaint.org'
> Subject:	RE: B sections
> 
> snip<
> Per Steel Construction, by AISC, December1927.  p. 17.
> 	A-9 steel
> 	Tensile strength 55,000-65,000 psi
> 	Yield point 0.5 tens. str. 
> 
> Avoid welding to these beams.  It can be done, but only with great care.
> 
> Regards,
> Harold Sprague>
> 
> Harold, B sections were used well into the 1960's and found fairly common
> in
> remodels. Is there problems with welding all of them? Did I miss
> something?
> what should we be aware of about welding to them??
> Matt Jordan
>