welding 0Cr13 and 0cr18Ni9

Date 10-11-2007 13:38

Yes, for most processes heat input is a supplementary variable. QW 409.1. If you don't have a Section IX it is evident you should have.
And if you notice, the variable is displayed as '> heat input input', essentialy meaning the heat input is recorded as a maximum. Measure your travel speed, determine volts and amps, plug em into the formula and voila'. Then everything underneath that result is acceptable, code wise.
But a word of caution, contrary to popular belief less heat input does not necessarily provide better impact results, and more is not necessarily deleterious. Though predominantly this is so, and especially when you're starting out with fine grained materials and determining HAZ's. Some notable exceptions can be when CVN's are determined as lateral expansion, or when greater heat input may actually broaden the fine grained HAZ of large grained materials when your doing HAZ impacts (and keep in mind that multi pass weld deposits have HAZ's too). The point of trouble is actually when the large grain HAZ begins to broaden. Therefore, with some alloys in some circumstances the best heat input is more of a window than a minimum.
Where's the window? That's why we do the tests.

By Junbao Zhang (*)

Date 10-12-2007 14:15

I forget to say it is a welding procedure qualification for nuclear project. so It is very important.
so I want to know if heat input is a suppemental variable.Please say straight!very thanks!

By js55

Date 10-12-2007 16:50

Yes. WQ 409.1
Nukey huh?
Make sure your Charpies maintain the 1/4 thickness min.
Try to avoid fine grained materials for PQR Impact quals, you will have a very tough time equaling or exceeding the toughness of the unaffected BM.
However, if its a new nukey the new code accomodates the notorius problems associated with this antiquated requirement and allows acceptance if the minimum impacts are a certain amount over 40mils.

By Junbao Zhang (*)

Date 10-13-2007 00:40

Because it is a fillet weld procedure qualification, so only macro-examination will be performed, impact test can not be required.under the conditions, heat input will be required? if yes, so how to record it because it is manual TIG?
Thanks. best regard!

By 803056

Date 10-13-2007 16:47

Hello js55;

Wouldn't you have to refer back to the applicable ASME construction code to determine if Charpys are required. If they are, wouldn't a standard butt joint be required to determine the mechanical properties and to provide the necessary Charpy samples? Likewise, once it was determined Charpys are required, the heat input would be considered to be an essential variable.

To make things more interesting, the issue of fillet weld qualification is added into the mix. Unless the fillets are for non-pressurized welds, wouldn't the need to have a qualified welding procedure lead back to the need to verifying the mechanical properties via the welding of a butt joint as per QW-202.2(c)? If I'm reading the paragraph correctly, only non-pressure retaining fillet welds can be qualified by depositing a fillet weld and evaluating the macro-etched cross sections.

As for determining the heat input for a manual welding process, I record the welding parameters such as voltage, amperage, and travel speed for each pass. Since it is a manual process and since it is nearly impossible to have no variation in the welding parameters, I use statistics to establish the median heat input for the completed weld. That's were the MSExcel spread sheet comes in handy.

Best regards - Al

By MBSims

Date 10-13-2007 20:03

If you are doing this for nuclear work and don't already know the requirements, then you have no business doing this work. You need to bring in the appropriate welding engineering support to do this right.

By Junbao Zhang (*)

Date 10-15-2007 01:28

Because the welding procedure qualification only for fillet weld, so impact test can not be performed.
If heat input is required, the presure-retaining weld wil be qualified by butt weld? Otherwise, requirement for heat input become no meaning.in a other word, i thick it will not required because it is a qualification for fillet weld.is it right?

By MBSims

Date 10-15-2007 02:39

No, if you are performaing a fillet weld on impact tested material the procedure will require impact testing. This may require a groove weld qualification test in order for the impact specimens to be removed from the HAZ readily.

By js55

Date 10-15-2007 13:31

Al,
Yes. And thanks.

Marty,
I couldn't agree more. Coming to this forum for nukey qual info certainly cries out for obtaining greater expertise. Yours is the best advice yet. And this is no time to go cheap either. Go get the best.
And that is exactly what I did on my first one. Couldn't have been successful without it. Nukey quals for impacts can be difficult to say the least (that dayum antiquated unaffected base metal thing). The thinking is different. And there is no common sense or gray areas when it comes to verification on these things. People get weird.

By ssbn727 (*****)

Date 10-15-2007 15:21

Sounds like the one making the "Query" is a bit "Wierd" Jeff!

I mean, he registered in 1969??? I do'nt think the forum was online then. :( :( :(

This person reads like someone who's not being honest to us as far as one's validity toward their origin is concerned so, I suggest to be careful as to the type of info we share with this entity with respect to national security concerns.

My "Spider senses" are sooo out of control from this query so, to the rest of us here, let's be cautious as to what we share! I only hope that I'm wrong about this but, let's not take any chances especially when it comes to "Nukey" info. ;)

Respectfully,
Henry

By js55

Date 10-15-2007 15:29

Advice well taken.

By MBSims

Date 10-15-2007 23:18

Just out of curiosity, does your Authorized Nuclear Inspection Agency agree that impact testing is required?

By Junbao Zhang (*)

Date 10-16-2007 01:07

The inspection agency think the impact test is not required.at first, I think it is a must, but later, because it is a fillet weld , no method to test the property, so i change my idea.

By js55

Date 10-16-2007 13:51

There shouldn't be any ambiguity on this. The beauty of Section III is that it is much easier to decipher and understand than say Section VIII (the queen mother of all impact testing) or B31.3 (its ornery stepchild). These codes are very complicated. And as complicted in whether or not you actually have to do it, as they are in how to go about doing it.
Section III really isn't that complicated. The hard part of Section III is, as I said, the HAZ results equaling or exceeding the unnaffected base metal and sometimes even finding proper fillers if its an old plant licensed for a Section IIC filler that may not even exist any more. Oh yeah, and the fact that you don't really disposition anything (I suppose you can but who's gonna take that responsibility?). If its wrong, you cut it out, so there is no room for error. That'll get ya a few nights watchin the late show.