Welded With E-7018 Electrode Without Proper Baking -What Is The Action?

Maybe your procedure, or the code you are following, already has provisions for dealing with variances. If so, proceed accordingly. (For instance, ask your vessel or piping code inspector.)

Depending on what your code or inspecting agency allows, a reasonable strategy would be to radiograph randomly some fraction of the welds. If all or most of them pass, you might be able to accept the lot. If a significant fraction of them fail, you might need to radiograph more, or even all, of the joints. And of course any defects found must be repaired.

I don't know what percentages to suggest here; it depends on your local requirements.

I agree with Tornado. Especially with the suggestion of radiography. One thing to consider is that it would be important to understand the type of defect discovered (if any) to differentiate the likely cause. This is important because some defects are more likely the result of improperly baked (dried) electrodes while others are not. For instance, if a joint or two is rejected for LOF, this is likely due to technique and not related to excessive moisture in the electrode. The two defect types I would be concerned with as a result of excessive moisture would be porosity and inclusions (from the flux breaking off and not becoming consumed)

Again with agreement to Tornado, the WPS may already have a provision for dealing with non conforming materials. That should be your first check. If after your radiography reveals that all joints are fine, you would then convey your discovery to your customer and request a deviation. (Or whatever your company uses for NCR activity)

A likely defect resulting from welding with improperly-dried E7018 mild steel electrodes is hydrogen-induced cracking. These cracks form within 24-48 hours after the completion of welding, and usually start at the root of the weld and propagate upward through the fusion-zone and sometimes run off to one side into the heat-affected zone. Possible remedial steps include:

1. See what types and amounts of defects are permitted by whatever specification or code you are working to. Usually, no cracks are permitted.

2. Use RT or UT, coming into the weld from one side of the joint to look for linear or planar indications that run from the root up into the fusion zone.

3. Remove defect-regions by grinding or arc-air gouging, followed by grinding to "bright, clean" metal. Repair weld per a qualified procedure.

Two useful references are;

1. Yeo, Interrante and Dalder, Welding Journal, 1969

2. Stout and Interrante, Welding Journal, 1964

1st check with the tank inspector to look on the applicable code but if it say check with RT or UT I think practically it's better to check with UT because it's very clear for Incomplete Penetration due to high lo and Incomplete Vision.

dalder is correct in #3

Though you may find porosity by the appropriate NDT methods, but not HIC.

best is to remove the weld and reweld.