Test on pipe in 6G position

By hogan

Date 12-13-2007 23:00

ceramic backing is not prequalified. you will need to run a pqr per section 4 (d1.1)

By js55

Date 12-14-2007 14:44

Table 4.1
All except CJP's on TYK's.
And there are notes for the PJP TYK's.

I don't see where the qualification text addresses the ceramic backing explicitly in the context of qualfication.
But Section 5.10 says roots may be backed by,,,,,,,,,,,,,
So initially I would have to say the answer to your question, with the note proviso's I posted, is yes.
Given of course your one sided CJP qual test without backing or backgouging as you mentioned.

By js55

Date 12-14-2007 14:47

And from a practical standpoint I would approach this from an ASME perspective.
And say why not?
If you qual without backing from one side (typical ASME method) is there evidence that ceramic backing has a negative impact upon the weldment?

By rvarpazos Date 12-17-2007 21:28

I think the same. According to D.1.1, backing other than steel shall be qualified in accordance to the section 4. Table 4.5 (34) of the section 4 of the code says that "the omission but not inclusion of backing or backgouging". Therefore, a qualification test without backing qualifies welding with backing. The backing material isn´t a essential variable in table 4.5. Also, the inclusion of backing material doesn´t have a negative impact in welding, but it makes the welding penetration easier.

By ctacker (****)

Date 12-17-2007 22:56

"Also, the inclusion of backing material doesn´t have a negative impact in welding"

unless its a cyclically loaded nontubular connection with welds transverse to the direction of computed stress! (5.10.4)

By rvarpazos Date 12-17-2007 23:15

I was refering to ceramic backing, that is always removed. Section 5.10.4 is referred to steel backing left in place.