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[MW:12832] Nick break test failed

By Materials & Welding
 

Process: WPS qualification for SMAW through thickness double repair
Electrodes: root pass E-7018, HT, fill and cap E-7018-1
Code: API 1104
Pipe Diameter PQR: 24"
 
ISSUE:  2 of 4 specimens failed on Nick break test showing porosity and slag.
 
My questions:
 
1.- Can I support with only 2 passed test that the WPS is approved?
2.- Why codes ask for soundness tests like bend and nick break for WPS qualification?, I mean we would just need to test mechamical properties like tensile, hardness, charpy, etc
3.- It is a fact that the cause the test failed was because welder workmanship not the pocess is bad
 
Thanks for help me.


Eduardo Calva

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