1104 Optional Nick Break

By jarsanb (***)

Date 10-01-2007 17:51

I'll take stab......I have the welders put in this optional notch. The purpose of the nick break for welder qualification is to examine the weld metal soundness. So I like this break to start in the middle of the face and run as true through the center to the root as possible, unless it is to follow a discontinuity. The Branch/Butt "Multiple" qualification test is usually done on .250" wt. More times than not, if this notch isn't present, the weld will tare off to one direction with a large portion of the pipe wall present in the specimen. We have some continuity tests performed on .154" wt pipe. Without this notch it never breaks through the weld. Also, ER70 are the minimums for electrode strength, pipe wall strengths can be much less.

By js55

Date 10-01-2007 18:24

Thanks.
Thats excellent.
Any explanation as to 1104's mentioning mechanized and semi auto specifically. Clearly your experience has been that mechanized and semi auto isn't necessary to cause the the failure to run through the pipe so you've decided to just exercise the option.

By jarsanb (***)

Date 10-01-2007 18:48

No official explanation, my guess is because the fillers are generally higher in strength for the semi's along with the fact that the "as welded" deposits with rich argon sheilding come in significantly higher than minimum AWS specs. (Hobart - Lincoln pdf's) But you're right, I use the notch option as it's stated but if I'm testing thin wall 1/4" and less - SMAW welded - I will notch because of past experiences. A small score across the face from nick to nick is all thats needed.