TIG weld on Mild Steel_WPS parameters

Question

TIG weld on Mild Steel_WPS parameters

(OP)

9 May 14 16:17

Hi,
I have an old wps which I am trying to correct. It's for TIG welding of 1/2" inch thick plates with V-butt joint in flat position. It states 6 passes with 3 layers(1-root, 2&3-2nd layer and 4,5,&6-3rd layer). It specifies following parameters for all passes with 3/32" filler diameter.

Voltage : 20-21 V
Current : 100-160 A
Welding speed : 2.5 in/min

I guess only the root pass should be with TIG and the rest with MIG. The current range for TIG should be higher than above and also for higher passes, around Please let me know if I am right on this one and what should be these values. Also, what should be the interpass temperature requirements?

Thanks
Pranav

gtaw (Structural) · Answer 1 · 2014-05-10 12:07:27

The most common response found in this section is most likely:

"What code are you working with?"

Best regards - Al

pranavmontreal123 (Mechanical) · Answer 2 · 2014-05-12 09:49:55

RE: TIG weld on Mild Steel_WPS parameters

pranavmontreal123 (Mechanical)

(OP)

12 May 14 09:49

Forgot to mentions that. It's as per AWS code.

fishbox58 (Materials) · Answer 3 · 2014-05-12 11:13:48

That's D1.1 right? By the look of your welding speed and wire size your WPS is for GTAW on all passes. The WPS your are trying to correct should at minimum record the processes. I would start at the beginning with a new WPS.

pranavmontreal123 (Mechanical) · Answer 4 · 2014-05-12 12:14:13

Yes, it's D1.1
In this case, is it advisable to use TIG on all passes? Also, what about other parameters? Does the range sound good for current, speed and volts for all passes?

gtaw (Structural) · Answer 5 · 2014-05-12 17:26:03

If the WPS is for AWS D1.1, it had to have been qualified by testing per clause 4. That means they has to be a PQR listing the parameters used when the test assembly was welder. If there is no supporting PQR, go directly to jail, do not collect $200.

Without a supporting PQR, the WPS is unsupported and is not valid for structural welding.

If there is a PQR, I would question the voltage. The voltage sounds very high for GTAW with DCEN and Argon shielding gas. If the parameters are questionable, the entire PQR is suspect.

Best regards - Al

weldstan (Materials) · Answer 6 · 2014-06-09 11:44:26

The arc voltage is way too high unless helium was used as the shielding gas; however, they probably took the voltage readings across the leads at the power supply.

pandithan (Mechanical) · Answer 7 · 2014-06-10 08:57:54

it is difficult to note down Voltage for manual welding process like GTAW< SMAW etc

rodofgod (Materials) · Answer 8 · 2014-06-27 05:37:00

RE: TIG weld on Mild Steel_WPS parameters

rodofgod (Materials) 27 Jun 14 05:37

Why is it hard?

DekDee (Petroleum) · Answer 9 · 2014-06-27 07:43:39

RE: TIG weld on Mild Steel_WPS parameters

DekDee (Petroleum) 27 Jun 14 07:43

Agree with ROG - why is it hard ?

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TIG weld on Mild Steel_WPS parameters