2 Questions on Amperage Ranges

Date 07-16-2008 19:26

Question #1
ASME Section IX para QW-409.5 allows amperage or voltage variation of +/- 15%;
ASME Section IX para 409.10 allows a change in amperage of +/- 10%;
ASME Section IX para 409.23 allows a change in amperage of up to 10%;

Which is true? 10% or 15%? Also para 409.23 seems unnecessary and superfluous - is there a reason for this to exist?

Question #2
I have a series of ASME Section IX weld procedures derived from a single supporting PQR which lists the voltage range as "0-210 amps" and "0-24 volts". How can a single PQR which produced a single test coupon in a single position using a single diameter filler record ranges from 0 to 210 amps? Is this PQR and all of the spawned weld procedures invalid?

Thankyou

By 3.1 Inspector Date 07-16-2008 19:51

Look at QW 250 to 256, there you will see which QW you have to use for each process and if it is a essential, supplementary or a non-essential.
For most(if not all) heat input is a supplementary essential, which means thats its not applicable if you dont have impact test.

Yes, the procedures seem valid, if impact is not required.
However writing from 0 - 210 amps seems a little loose in regards to professional etiqette :O

IMO the WPS should be within reasonable range(+/- 25%) of the PQR, otherwise some of the points with a WPS is gone....
But according to ASME sec. IX it seem OK.

BUT remember, the manufactorer is responsible for the WPS and the welds done in production.

By tom cooper (**)

Date 07-17-2008 19:32

Thanks for pointing me to QW-250 to QW-256. I am amazed that I never noticed amps and volts are nonessential unless impact is a req't.!!!!

In my case, my own GTAW WPS would imply that any amp setting between 0 amps and 210 amps will yield an acceptable weld. I suppose I am free to revise these WPS ranges and simply apply values from a manufacturers data sheet and I will not have to retest.

By js55

Date 07-18-2008 13:53

Tom,
Amps and volts aren't supplementary variables either. Heat input is.
Thats why it really chaps my hide when some idiot does the heat input equation using the maximums of my WPS and says I am violating the code.

"Well, how do you enforce the heat input on your welders if the max numbers exceed the max heat input?" They ask.
"The same way I enforce them to not violate the max amps and volts." I say.
It never works. But it is a fundamental misunderstanding of Section IX.
I suppose the underlying assumption is that welders are bright enough to understand amps and volts but too stupid to understand heat input. An opinion of which I vehemently disagree.