Backgouge ASME IX

By ctacker (****)

Date 11-02-2012 01:07

I'd be concerned too, I am always concerned when the lead welder suggests anything.
All kidding aside, are you asking a question?

By Jovi Zhu (**)

Date 11-02-2012 01:19

Jeff,

My humble opinions:

In QW-256 table, QW-410.6 (A change in the method of back gouging) is listed as a nonessential variable.

Your WPS must address all essential and nonessential variables (Also the applicable supplementary essential variables when other Sections of the Code require notch toughness qualification). See QW-100.1

But your PQR doesn't need to document this nonessential variable. See QW-100.1

When your specific product configuration make the internal backgouge impractical, you can editorially amend your WPS or make a new one to remove the backgouge requirement. The change of this nonessential variable doesn't require requailification of the WPS. See QW-200.1 (c)

Thanks

Jovi

By Shane Feder (****)

Date 11-02-2012 05:32

jeffr72,
QW 402.4 is an essential variable for Welder Qualification only.
If your welders did a test coupon welded both sides with backgouging they couldn't weld pipe (unless they can get inside and backgouge / backgrind).
If you run a PQR on plate you can write one WPS for plate and one WPS for pipe, no problem. (see QW 211 & 212)
Regards,
Shane

By Jovi Zhu (**)

Date 11-02-2012 06:09

Agree with Shane.

jeffr72,

Go to Article II (QW-256) for PROCEDURE QUALIFICATION and go to Article III (QW-356) for PERFORMANCE QUALIFICATION. Big difference~

Section IX book confused lots of people~

By jeffr72 Date 11-04-2012 10:35

Thanks guys,

Shane, I am new to this and Section IX is a bit much :)

I agree that you would have to backgouge pipe if I went with this coupon, but I couldn't for the life of me find out where it says this. I saw that a double v is considered a weld with backing and that + backing is allowed but after that I was lost.

I'll read the two articles again that you mention.

Jeff

By Jovi Zhu (**)

Date 11-05-2012 02:38 Edited 11-05-2012 02:43

Jeff,

You are not the only "lost" one having a hard time dealing with Section IX book. Too often, dealing with the detailed wording of this book blocks us from seeing the whole picture.

First of all, Section IX is about welding procedure and performance qualification. Backgouge is an essential variable (for performance) as required by Section IX to be qualified by the manufacturer himself. In other word, Section IX doesn't give you guideline on whether backgouge is needed for your specific application but rules of how to qualify.

Another way to say: Section IX is just a QUALIFICATION standard other than a welding HANDBOOK. See the front cover.

Why is backgouge an essential variable for performance qualification, but not for procedure qualification? Here is the answer:

QW-401.1 Essential Variable (Procedure). A change in a welding condition which will affect the mechanical properties (other than notch toughness) of the weldment (e.g., change in P-Number, welding process, filler metal, electrode, preheat or postweld heat treatment).

QW-401.2 Essential Variable (Performance). A change in a welding condition which will affect the ability of a welder to deposit sound weld metal (such as a change in welding process, deletion of backing, electrode, F-Number, technique, etc.).

That is to say, the ASME Section IX Committee believes that backgouge doesn't matter very much to the ABILITY of the Procedure to make weldment of acceptable mechanical properties, but it does matter a lot to the ABILITY of the Welder to deposit sound weld metal.

With the application of backgouge, a welder can have a good time making a sound weld metal. But without it, he may have a hard one.

Your lead welder was giving a good suggestion on how to easily make the weld metal sound. If other product configuration of yours make the backgouge impractical, you will need to find other ways(e.g. to qualify a welder without backgouge).

Thanks,

Jovi

By 803056

Date 11-06-2012 14:53

This is a common quandary for people using ASME Section IX; how to address groove details.

I subscribe to the philosophy that the WPS is a recipe that the welder follows when making a code compliant weld. The recipe should provide all the information needed to make a weld that provides the mechanical properties and the integrity needed to meet the specific requirements of the construction code. With that in mind, a WPS that simply meets the minimum requirements of Section IX may not meet the requirements of the construction code or the needs of the welder.

Section IX lists the groove details as nonessential, thus some people simple list "All Grooves and All Fillets" under the heading of Joint Details. While many individuals are of the opinion that is sufficient, there are just as many people that would argue the welder needs more information. I side with the latter. The welder needs sufficient information to make the weld required without stopping to ask questions such as what groove type is required, what groove angle is required, what root face is required, is back gouging needed, etc. Many of those questions can be addressed by the welding symbols given by the drawings. That is assuming the detailer used standard welding symbols (not required by ASME) on the drawings and all the needed information is provided. My experience is that most mechanical drawings do not provide sufficient information or the welders would not have to ask the questions we frequently see here in the forum.

This is where someone chimes in and makes the comment, "If the welder is experienced, he would know what is required."

That is a cop out in my opinion. There are many contractors that work to several welding standards, sometimes they are working with more than one welding standard on a single project. It is silly to assume the welder "knows" the requirements for each of the welding standards. Few welders have had an opportunity to study a single welding standard, never mind several. The WPS offers a vehicle that can be used to provide the information that is code specific. There are several ways to accomplish the desired result. The WPS can be a general WPS offering the bare bones information needed used in conjunction with a system of annexes that provide code specific information such as how an integrally reinforced branch fitting is to be fitted to a run pipe and welded, whether the slip-on flange is to be welded on the ID as well as the OD, the size of the fillet weld required for a socket type fitting (it is different for B31.1 versus B31.3 for instance), etc. An alternative is to develop specific WPSs for each type of connection. The latter becomes rather unwieldy, but it is required for some DOT projects.

The bottom line is that the information provided to the welder should be sufficient and complete to the extent that a welder (without twenty years of experience) knows what must be done to provide a code compliant weld. You cannot expect the welder to be conversant with every welding code known to man (even if your upper management believes that to be self-evident).

Best regards - AL