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RE: [MW:12378] Welder Qualification for MIG welding(Short-circuiting transfer)

By Materials & Welding
Hi Prasu,

Short Circuiting transfer involved the lowest range of welding currents. It produces a small, fast freezing weld pool. Weld metal is only transferred from the electrode to the work piece only when the electrode comes into contact with the weld pool (Circuit completed). As soon as the electrode melted and broke off, the circuit is broken and there is no metal transfer across the GAP.
These process of short circuiting and the use of low current system introduces a major defect like, lack of fusion (side wall or inter run). These lack of side wall fusion might not be clearly define in Radiographic films so the use of Bend test is to show if the defect exist upon stressing the joint.

Regards,

Rems Okonkwo
Welding Engineer
Nigerdock Nig. PLC-FZE
Snake Island Integrated Free Zone
Apapa, Lagos, Nigeria
Mobile: +234 (0) 806 330 5867
+234 (0) 1 660 1514
Email: rems.okonkwo@nigerdock.com
Web Site: www.nigerdock.com

-----Original Message-----
From: Prasu Cutie
Sent: 08/09/2011 6:15:20 am
Subject: [MW:12371] Welder Qualification for MIG welding(Short-circuiting transfer)

Dear Experts,

As per ASME Sec-IX, Welder qualification for MIG welding(Short-Circuiting
transfer) testing must be done by Bend test only rather than RT or UR like
for other mode of transfers.
What could be the exact technical reason behind this requirement??????
Can any body explain me at the earliest please!!!!

Regards
Prasu

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