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Up Topic Welding Industry / Inspection & Qualification / Quick Question: PQR Preheat and Interpass Temp Measure
- - By Bowler_Hat (**) Date 10-27-2015 16:22
Hey All,

Just trying to build up the tools i need here to perform a PQR and have all the details squared away.

What is your preferred tool/method for nabbing what the pre and interpass temperatures?

Myself, while Tempilstik are the most accurate (+/-1%), it seems that one would have to own an almost complete set of their contact polymers to know what the temperature is.

The Estik by Tempil has a +/-2% tolerance, and covers from 0°C - 537°C.

My work is usually close and personal, so the appeal of distance with an IR pryometer doesn't quite appeal.

Any insight would be greatly appreciated (don't want to startle my company with a 6 sheet purchase request for all the different tempil sticks...and even then, that doesn't cover your ambient temperatures.)
Parent - - By welderbrent (*****) Date 10-27-2015 23:15
Regardless of the selection of an IR gun or contact probe pyrometer they must be calibrated at least annually.  IR guns, As long as you get a good one such as the Fluke 561, have a very good range, up to 999°F I believe, and can be used from very close range to several feet away which has many advantages.

Remember, most preheat and interpass temps are MINIMUMS but under some codes you will also need to watch your maximum limits.  And, as you mention, accomplishing all the data recording for the PQR is more exacting than can often be accomplished with Tempilstiks, even with the whole set which is a little expensive. 

Hopefully Al or one of the others will pitch in and offer some more complete advice.

He Is In Control, Have a Great Day,  Brent
Parent - By 803056 (*****) Date 10-28-2015 01:24
I use a thermal couple initially and then check it with an IR thermometer. If the readings are reasonably close, I use the IR because it is faster and less intrusive.

When using the Thermal couple, cover the junction with a glove to get the best reading.

Parent - By TimGary (****) Date 10-28-2015 12:00
Temp Sicks are great, but terribly inaccurate and often used incorrectly so supply misleading info.
IR Laser devices are extremely handy, but again can supply misleading info, especially when reflectivity is an issue. I've seen 100 F differences an inch apart of the same piece of steel, depending on if the laser point was on mill scale or a grind mark.
IR Thermometers and contact pyrometers are best for critical functions when accuracy is a must.

Up Topic Welding Industry / Inspection & Qualification / Quick Question: PQR Preheat and Interpass Temp Measure

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