what is a PJP-FS weld

[REGRUMBLE]

We received drawings with PJP-FS in the weld tail of a 1 1/2" plate "T" joint. When I called the engineer he indicated that he wanted a partial joint penetration full strength weld. I wanted to know what size bevel and fillet combination would achieve full strength and he indicated that I should just refer to the ASME code for the answer. I cannot find anywhere that indicates what size weld is required to achieve partial joint penetration full strength.

 

[gtaw]

What does the engineer consider to be a full strength weld?

Every welding standard I am familar with reduces the allowable stress for fillet welds and partial joint penetration welds due to the notch-like stress riser that is naturally present in the weld root.

I assume it is possible to obtain a full strength weld using a PJP if you are welding unobtainium, but other than that, codes require CJP if 100% joint efficiency is expected.

Best regards - Al

 

[Duwe6]

PJP's are adored by the fitter. The land left allows him/her to jam the T-joint togather and yell "Tack".

My favorite configuration is a 1/8" land in the middle of a double-bevel 55° joint prep, with reinforcing fillets. See BTC-P5. For some reason AWS thinks that SMAW will leave 1/8" at the back of the bevel unweldsd "Effective Size = (S1 + S2)-1/4" But they think GMAW will penetrate the prep all the way in. Horsehockey on both theories.

So taking the 1/4" penalty, you need your 2 reinforcing fillets to add up to an effective throat of 3/8", 3/16" per side. Your Fillet leg size is 3/16" * 1.414 = .265" = 5/16" fillet, both sides. Easy, and essentially free, as the welder had to add some fillet reinforcement to get his partial-penn groove weld to fair-in properly [in most welding positions].

Or 'Mig' weld - GMAW - it and ASSume that AWS is right about full-depth welds and only add minimal fillets to compensate for the 1/8" root face - land.

 

[gtaw]

I think there is a misunderstanding somewhere along the line. Both BTC-P5 and BTC-P5a require the designer to "down size" the weld by 1/8 inch per side to account for the uncertainty that the welder will achieved fusion to the root of the groove when the groove angle is less than 60 degrees.

Of course let us not forget that the contractor always has the option of demonstrating his proficiency by qualifying the welding procedure using the proposed groove detail if it is felt the prequalified joint details included in the AWS structural welding codes are too conservative.


Best regards - Al

 

[racookpe1978]

"When I called the engineer he indicated that he wanted a partial joint penetration full strength weld. I wanted to know what size bevel and fillet combination would achieve full strength and he indicated that I should just refer to the ASME code for the answer. "

Gee. What a helpful "engineer" you called ...

"Gosh, I can't ell you what I drew on my drawing, so I'll just tell you (the guy who will actually build my contraption based on my design) to "go look it up in the AWS on some unknown page to some unknown paragraph using some unknown process spec ."

/sarchasm = That gaping hole between the real world and a designer's fantasies 8<)

 

[REGRUMBLE]

Our customer told me to look at “Design of Weldments”, by Omer W. Blodgett from “The James F. Lincoln Arc Welding Foundation” where they outline the requirements for partial pen full strength welds. I must admit that in all the years that I have been in this I have never seen this book used to specify weld sizes on code work.