Boron in deposited weld metal

[MWinczewska]

Can somebody advice regarding welding consumable for Carbon steel grade 450
New Project specifications require: content of Boron (B) in deposit weld metal cannot exceed 0.0005% for welding base materials with SMYS of 415 MPa or greater.. Have somebody preformed review of the inclusion of Boron as part of weld consumable certification?
Boron content below 0.0005% seems to be very low for me..
Maybe it is a mistake in the new specification..???

 

[cloa]

They generally avoid boron like crazy as very little give very high hardenability- ie. a little will give you martensite in the HAZ.

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[metengr]

MWinczewska;
I doubt it is a mistake. Unfortunately, rod and solid wire for welding consumables can be manufactured from re-melted scrap that can result in certain tramp elements below threshold reporting levels. Boron is a potent hardenability agent for carbon and low alloy steel, and could be introduced when formulating welding consumables from scrap. I have never looked for boron nor requested it to be reported as part of a review of weld rod or wire certification.

 

[TVP]

Here is one reference on the subject:

Weld Cracking Linked to Wires Containing Boron

http://files.aws.org/wj/2006/11/wj200611/wj1106-28.pdf