Hi Guys,
I posted this response on "Shop Talk" but I am still keen on seeing if I can get info on my last question and thought if I posted it twice I would double my odds,
Thanks and regards,
Shane Feder
Theophilus,
Greetings from "Down under".
My first question is does nitrogen purging gas contain any non-inert gases.?
The reason I ask is I am currently working on a 1 1/4 chromolly welding procedure and I am researching addition/deletion/composition of purge gases.
QW 256 (GTAW welding variables) lists relevant Gas variables as 408.2,408.5,408.9.
408.2 covers shielding gas.
408.5 (...."a change in backing gas composition",.... is a non essential variable.
408.9 " For groove welds P41 through P47..... (you mentioned P43 material),the deletion of backing gas or a change in the nominal composition of the backing gas from an inert to a mixture including non-inert gas(es).
If nitrogen is a full inert gas does this mean that changing between Argon and Nitrogen does not require requalification of welding procedure ?
Also,are there guidelines anywhere on what percentage of chromium is considered the minimum before purge is required on chromolly piping ?
Regards,
Shane Feder
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