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RE: A36 Bolts

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A36 material and A307 material are the same.  The only difference is
that A307 bolts are manufactured in large lots per ANSI specifications
and theoretically A307 bolts are tested.  In reality most (95% or
greater)  A307 anchor bolts are manufactured from A36 material and are
not tested because of the small lot size.  Standard A307 anchor bolts
are difficult to find in lengths greater than 10 inches.

The industry practice is to manufacture A307 anchor bolts by threading
and hot heading the head, and testing is ignored.  Because of the small
difference in allowable stresses the problem is more academic than real,
but I still prefer to thread both ends of an A36 rod and deform the
threads on the anchored end.

The weak link on most bolts is the head, and I don't have to worry about
the integrity of an untested hot headed anchor bolt.

By the way, hot heading is the process by which the end of the bolt is
heated to cherry red.  The end is impacted to flare.  Then the shoulders
are sheared off to form the hex head.  The wedge test (the test for bolt
head integrity) is an optional physical test of the bolt.

Harold Sprague
Black & Veatch
From: Liu, Shu-Shang
To: 'seaoc(--nospam--at)'
Subject: A36 Bolts

Date: Tuesday, September 23, 1997 11:01AM

I am reviewing a design.  The designer uses A36 anchor bolts for
anchoring large diameter butterfly valves in a high seismic area.  I
have not seen people use A36 for anchor bolts.  Is A36 suitable for
making bolts?