Dear Sir,--Thank you for valuable comments. Please see the attached WPS and PQR which I have prepared for production and welder qualification.
On Friday, March 1, 2019 at 9:51:24 PM UTC+6, pgoswami wrote:This technique is NOT "Tandem GTAW". This term applies to machine or automatic welding processes, when one electrode is the lead electrode and the other is the trail.
The picture depicted here is a modification of the GTAW welding technique, where 2 welders are welding in the same welding puddle at the same time. In shop floor coinage the technique is called, "Double Operator TIG (DOT process)" to avoid costly back chipping in Stainless welds. I know in the 1980; L &T used to adopt this technique a lot and when it was convenient.
What's required:-
· Qualify a PQR, with the identical welding condition for the root, followed by rest of the process by other welding techniques. For GTAW the heat input is doubled. Hence corrosion properties may be affected.
· Qualify welders to Sec-IX, with identifiable pairs and document The same.
· Use these pairs only in production welds
· Both welders should use filler metals, or else chances of crater crack would exist ( due to the fact, more volume is melted but less filler wire is added).
Duplex SS calls for severe restriction of heat input, hence this technique may not be advisable. However if trials yield good results then it may be thought of at the discretion of the welding engineer and the AI.
Thanks.
P.Goswami.P.Eng, IWE.
Independent Welding & Metallurgical Specialist
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From: material...@googlegroups.com [mailto:material...@googlegroups.com] On Behalf Of anam...@gmail.com
Sent: February 28, 2019 11:39 PM
To: Materials & Welding <material...@googlegroups.com>
Subject: [MW:29173] TIG Tandem Welding qualification as per ASME-IX
Dear expert,
How I can write a WPS and qualify welder as per the following picture. In this picture, one welder will weld with filler metal opposite welder without filler. Please need your valuable suggestions.
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