Welding A325 hi-strength bolt to steel tube

[ujinkim]

Hello,
I'm not familiar with the welding guidelines.

Is it possible to weld such a high strength material of A325 bolt with regular steel tubing?

Is there any consideration when we do this work, such as any strength limitation of the counter part material?

Thanks for your reponse,

 

[connectegr]

A325 bolts are (hardened) quenched and tempered. No manufacturer will guarantee their product if it is welded. The additional heat input of welding can cause stress risers and cracking.

http://www.FerrellEngineering.com

 

[Guest102023]

Weld or bolt, decide which, but never weld a bolt (at least not this grade).

 

[InDepth]

It really depends on the criticality of the connection. If it is lightly loaded and you have a good WPS for that situation that was qualified and tested, then it may work (i.e. get a good welder who knows sequencing and preheating conditions). I believe there is a ASTM Supplement that allows welding of this grade (look at end of ASTM 325 standard....or look at the equivalent threaded rod standard that is typically used for anchor rods).

In generally though, I would go with a Nelson fully threaded stud (

http://www.nelsonstud.com/Portal/Products/Fasteners/Catalog/tabid/58/Default.aspx)

or go with a hollow bolt.


......just really depends on what you want to use it for and what the loading condition is. I expect that the limit state would be your HSS.

 

[Duwe6]

Welding A-325's works well using E-7018 rods and at least 2 passes [layers]. Caveat is that after welding, bolt is no longer Quenched & Tempered. Calculate this bolt as a 'soft' Grade 2 bolt, nothing more.

 

[connectegr]

Duwe6
AWS and RCSC would disagree.

http://www.FerrellEngineering.com

 

[Ron]

connectegr is right...

Any benefit you have from using an A325 bolt will be negated when you weld it.

Agree that Nelson stud would be good; however, not every welding subcontractor has the capability; and technique is important. You can also buy the Nelson studs and weld them using conventional welding processes.

 

[Duwe6]

@ Connectegr: What I said [poorly] is that a welded A325 is no longer an A325, thus no longer acceptable for Structural connections. AWS does allow welding of this material, but since it is outside the prequalified alloys, you would be required to make a proper D1.1 [or whatever] welding procedure and run a successful PQR coupon to prove that WPS. Impractical for a Code weld. But if you just want a bolt for a misc. conn., like a small sign, A325's weld fine using E7018.

If ujinkim chooses to manually [SMAW, stick] weld Nelson studs, he should pry or knock out the 'load' from the tip of the stud. It is a small ball of aluminum added for deoxidizer for stud-welding, and is not needed for manual welding. Additionally, the aluminum will interfere with the flux mixture from the weld rod being used.

 

[ujinkim]

Thanks for all the comments. Finally, i choose to consult with Nelson.