UT of PJP per D1.1

By Bill M

Date 10-09-2008 16:23

What is the joint designation? Is it ground smooth? How thick are the plates, and how deep is the required penetration?

By trapdoor (**)

Date 10-09-2008 23:19

The joint is a single bevel groove and thicknesses range from 1/2" to 3/4". The depth of prep is t - 1/8".

By Bill M

Date 10-10-2008 12:33

Sounds like a tough UT consideration

If it was say a 2-inch plate, with a ground flush partial penetration weld 1-inch deep groove, you might have a swing at inspecting some volume of the weld.

By CWI555

Date 10-16-2008 11:10

Should be no problem with additional training of the tech and a specific procedure. The procedure itself will need to be qualified with Mockups as well as utilize a specific reference block for the task if you intend for it to have a relevant value.

Regards,
Gerald

By trapdoor (**)

Date 10-17-2008 05:15

Thanks everyone for the input. It's good to know that i was on the right track on this one.

By HgTX

Date 10-15-2008 21:52

This is one of those "as determined by the engineer" cases. D1.5, for example, even though it generally has stricter requirements than D1.1, only requires MT for PJP, and so also doesn't address how to deal with PJP.

We've had to require UT on PJP recently, and the fabricator had to develop a whole new procedure that looks not much at all like the D1.1/D1.5 procedure. I think they could have used something a lot more similar to D1.5 than what they came up with, but since we were operating outside the code anyway, we took what they proposed as long as it would get us comparable quality, and didn't worry about how similar the procedure was to the normal code.

One thing that helped was that as long as the weld extended beyond the theoretical limits, which with any amount of penetration it would, they didn't need to inspect every cubic millimeter of the weld right down to the actual root;they just had to get down to the theoretical throat depth. That way they could stay away from having to deal with the confusing reflection situation at the root of the weld. Once they figured out that we didn't need them to determine actual depth and soundness all the way down to that depth, they had a much easier time seeing how to do the inspection. I think, but wouldn't swear, that they made a point of making the prep extra-deep to ensure that they had enough penetration beyond the theoretical root location so that they could stay away from the real root while still giving us 100% inspection for the required weld.

Hg

By hogan

Date 10-15-2008 22:01

I have had to UT some PJP's in the past. There are two main things that can be accomplished by UT of PJP. First you can scan for depth of penetration, or you can perform a volumetric scan. Depending on your needs you should start with what information do you want from the inspection. depth of pen, volumetric, or both. Then you would probably want to contact a UT level III to write a procedure and test the technician.

By HgTX

Date 10-15-2008 22:16

Yeah, we needed volumetric. At first they thought we just meant depth, and they were gonna do a depth check every foot for the length of the weld. Boy were they disappointed when they found out what we really meant.

I wish there was more out there on volumetric NDE of PJPs. Because of the D1.5 requirements or lack thereof, designers may specify CJP where only PJP is needed, just because they don't want to lose the volumetric inspection. The current MT-only requirement is ridiculous--what's the point in inspecting only the outer 1/16" of a weld that is maybe an inch and a half deep?

Hg

p.s. Unrelated question: any UT techs out there who work primarily in metric units?

By CWI555

Date 10-16-2008 11:11

I have worked in metric units extensively. metric / standard, it all bounces the same.

By HgTX

Date 10-16-2008 16:23

How do you calculate the attenuation factor when your sound path is mm? Divide by 25, subtract one, multiply by two? Or subtract 25, multiply by 0.08? (I know the answer's the same, just wondering what's the best way to tell someone else how to do it.) Or something else? I just noticed yesterday that D1.1/D1.5 screwed up the metric part of this--they say subtract 25 then multiply by 2, which is silly. Clearly everyone knows what is meant and is doing something else, but it should get corrected.

Hg

By CWI555

Date 10-19-2008 06:41

It's all in getting the conversion right. Screw that up and your lost.

By kipman

Date 10-16-2008 15:17

TX,
I've worked most of the last 20 years overseas and did all my UT in metric. I'm never going back to US customary, i.e. inches (I wish I could somehow underline the word "never"). It is far easier working with whole numbers than it is with fractions.
Mankenberg

By CWI555

Date 10-16-2008 15:23

You can't underline it, but you can make it bold by typing [ b ] word/s [ /b ] without the spaces in the brackets. I agree with the metrics comment. So much easier and accurate in metric.

By kipman

Date 10-16-2008 15:42

Thanks for the tip, Gerald.
Mankenberg

By jwright650 (*****)

Date 10-16-2008 15:54 Edited 10-16-2008 15:56

sorry about going off topic, but here is a list of the "tags" and how they can be applied....

Markup Tags
For security reasons, mwForum only supports its own set of markup tags, no HTML tags. Available markup tags:(like previously stated do not use the spaces)

[ b ] text [ /b ] renders text bold = text
[ i ] text [ /i ] renders text italic = text
[ tt ] text [ /tt ] renders text nonproportional = text
[url]address[/url] links to the address
[url=address]text[/url] links to the address with the given text
[img]address[/img] embeds a remote image (if enabled)
[img]filename[/img] embeds an attached image
[img thb]filename[/img] embeds an attached image's thumbnail (if available)

By jrw159

Date 10-16-2008 16:11

John,
Thanks for the list, I was wondering how that worked.

jrw159

By jwright650 (*****)

Date 10-16-2008 16:34

You're welcome...BTW, all that info is under the help menu at the top of the forum.