Failure in Bend Test-Combination Process GTAW+GMAW As per ASME Sec.IX-Procedure Qualification
Failure in Bend Test-Combination Process GTAW+GMAW As per ASME Sec.IX-Procedure Qualification
(OP)
Hi,
Good Day Everyone
Code- ASME Sec.IX
Process - GTAW+GMAW
Type- Automatic Welding
Pipe Size & Material - Dia 6" Sch.80 (10.97mm), SA106 Gr.B
Welding Consumable used - GTAW-ER70S-2 (Shielding Argon 99.997%) and GMAW-ER70S-2 (Shielding 80%Ar+20%Co2)
GTAW Deposition-3.8mm, GMAW-7.17mm
100% RT acceptable joint.
Inspite of clearing 100% RT of PQR sample, our test sample was failed in Bend Test and found with open cracks, we are not able to make it why?, the welding consumable selection was according to the Electrode manufacturer and process selection was as per the Welding machine manufacturer, all the welding parameters were recorded and found the Maximum heat input as 1.9Kj/mm.
Can any one advice on this? so that we can goahead with some changes in Procedure Qualification.
Thanks in advance.
Good Day Everyone
Code- ASME Sec.IX
Process - GTAW+GMAW
Type- Automatic Welding
Pipe Size & Material - Dia 6" Sch.80 (10.97mm), SA106 Gr.B
Welding Consumable used - GTAW-ER70S-2 (Shielding Argon 99.997%) and GMAW-ER70S-2 (Shielding 80%Ar+20%Co2)
GTAW Deposition-3.8mm, GMAW-7.17mm
100% RT acceptable joint.
Inspite of clearing 100% RT of PQR sample, our test sample was failed in Bend Test and found with open cracks, we are not able to make it why?, the welding consumable selection was according to the Electrode manufacturer and process selection was as per the Welding machine manufacturer, all the welding parameters were recorded and found the Maximum heat input as 1.9Kj/mm.
Can any one advice on this? so that we can goahead with some changes in Procedure Qualification.
Thanks in advance.





RE: Failure in Bend Test-Combination Process GTAW+GMAW As per ASME Sec.IX-Procedure Qualification
RE: Failure in Bend Test-Combination Process GTAW+GMAW As per ASME Sec.IX-Procedure Qualification
RE: Failure in Bend Test-Combination Process GTAW+GMAW As per ASME Sec.IX-Procedure Qualification
If you don't want to crank up the heat then change your gas to at least 90/10 or better yet 92/8 composition. It's harder to maintain spray mode with 20% CO2.
RE: Failure in Bend Test-Combination Process GTAW+GMAW As per ASME Sec.IX-Procedure Qualification
RE: Failure in Bend Test-Combination Process GTAW+GMAW As per ASME Sec.IX-Procedure Qualification
As metengr and fegenbush have stated GMAW (especially short circuit) is susceptible to lack of fusion, both lack of side wall fusion and lack of inter run fusion.(both types of defects that can be missed with RT.)
Are they actual cracks or LOF - what did the laboratory state on your report ?
Try UT or a macro on the remaining coupon (either side of where the bend samples were removed.
I always maintain GMAW on anything above 8 mm needs to be welded as "hot" as possible to avoid LOF problems.
If it is a pipe welded with an automatic process I am presuming the coupon was in the 5G or 2G position - what was the torch angle ?
LOF in GMAW also comes from incorrect torch angle.
A bit more info - amps, volts, travel speed,position, torch angle and we may be able to help further,
Cheers,
DD
RE: Failure in Bend Test-Combination Process GTAW+GMAW As per ASME Sec.IX-Procedure Qualification
Do address Metengr & DekDee and other re short circuiting transfer.
RE: Failure in Bend Test-Combination Process GTAW+GMAW As per ASME Sec.IX-Procedure Qualification
Likewise, it is important to know the location of the defects that were observed when the guided bend tests were performed.
Assumes made by individuals trying to help you may be incorrect. We can only respond based on the information you provide.
Assumption:
Pipe welded in the fixed position.
Welding performed in multiple positions
GMAW transfer mode - short circuiting or pulsed (necessary for all position welding
Technique - unknown, but heat input suggest a weave technique was used.
Electrode diameter - unknown, assumed to be 0.035 to 0.045 inch
What else can you tell us?
Best regards - Al