Comments on: Welding High Strength Bolts

By: Troy C.

Troy C. — Wed, 22 Oct 2008 20:12:35 +0000

Can you tell me if an A615 Grade 75 threaded anchor bolt can be heated and straightened without reducing the strength. We have several bars that are roughly 8′ long which are bent about 1/2″ out of straight over the last 1′-6″ foot of length.

By: Adam Oakley

Adam Oakley — Thu, 09 Oct 2008 00:04:48 +0000

@Ted Welti: High strength nuts used with A325 bolts are heat treated and should not be taken past their tempering temperature (i.e. welding), since this can change the mechanical properties. Although, we often see engineer’s designs that include high strength nuts welded to plates. The main concern is that it is impossible to know, without testing, what effect the welding will have on the nut’s strength. Many believe that a few tack welds will not significantly alter the strength of the nut. We have no engineers on staff and don’t make any recommendations about this method.

By: Ted Welti

Ted Welti — Wed, 08 Oct 2008 17:04:41 +0000

Is it allowed to weld a nut to the back side of a steel plate for a slip-critical ASTM A325 bolt connection? There would be no welding done to the bolt itself, just the nut. The nut would be centered over a hole in the steel plate and welded to the plate in the shop. This is so in the field the bolt could be installed without access to the backside to hold the nut from spinning when the bolt was tightened. This is for attaching a brick shelf angle to the outside of a cold-formed steel wall that will be sheathed in the shop before being tilted into place in the field.

By: Adam Oakley

Adam Oakley — Tue, 08 Jul 2008 16:09:32 +0000

@Soo: A307 grade C is usually made from A36 steel which is weldable. Don't forget that ASTM has removed grade C from A307 and replaced it with F1554 grade 36.

By: Soo

Soo — Tue, 08 Jul 2008 08:15:03 +0000

what about ASTM A307 grade C..?
is it possible to re-use anchor bolts after welding?

By: Adam Oakley

Adam Oakley — Wed, 23 Apr 2008 16:33:00 +0000

@Ben Valdez: Any quenched and tempered bolt that has a minimum tensile strength lower than 150ksi can be galvanized. There is no problem galvanizing A193 B7. However, any quenched and tempered fastener (A193 grade B7 included) that develops its strength properties through a heat treating process should not be welded. If you need to weld to the fastener, the highest strength bolt available would be F1554 grade 55.

By: Ben Valdez

Ben Valdez — Tue, 22 Apr 2008 21:22:45 +0000

I am looking for bolts that are close to ASTM A193
B7 that are weldable and can be galvanized.