fillrer metal & welding defects 6

[glazetm]

Does anyone have a suggestion on a perferred FCAW all postion welding wire. We are currently using tri-mark(e71t-1) and ending up with prosity and worm tracks in our weld. Our sheilding gas is good; no fans are in the work areas. Any suggestions on what could be causing these defects?
Also many of our welders are failing VT inspections due to slag inclustions. Any tips on what to tell these welders to prevent this kind of mistakes.I am a welder by trade but now in QA/QC; I never had this problem over and over. My conclustion is the welder is running to cold and not staying in there weld puddle.
Any suggestions will help.
thank you all,

 

[stanweld]

Porosity: Check flow rate of gas at the torch, check dew point of gas at the torch, bubble leak test all gas line connections at the start of each shift, blow out wire guides at the start of each shift; check guides for excessive wear and replace if required.
Slag: Deslag after each pass; for the past 40 years I have heard welders state that the slag will float out of the weld and deslagging is not required - for 40 years they are still mistaken.

 

[metengr]

Also, other sources of worm tracks or chicken tracks in the weld deposit are

•From the air (high humidity).
•From the plate surface (condensation and/or excessive hydrocarbon contaminants, such as rust, oil, primer, etc.).
•From the wire (if wire packaging is damaged and/or wire is exposed to air for long periods of time, allowing condensation on the inner core elements to occur).

 

[gtaw]

The electrode extension is a very important variable that is often overlooked by the welding codes, thus not listed on the PQR or the WPS.

The electrode manufacturer usually has a web page listing the welding parameters for each diameter electrode. Look for a listing of the recommended electrical stickout, contact tip to work distance, or electrode extension. Different terms used to define how much electrode should extend past the contact tube. Some manufactures measure it differently, but they are all striving to provide the welder a piece of important information.

The electrode extension represents resistance in the electrical circuit. Ohm's Law states that as the resistance increases, amperage decreases if the arc voltage is held constant. Since your power supply used for FCAW is constant voltage, it is a safe assumption voltage will not vary more than a couple of volts. Any variation in the electrode extension is going to affect the current, thus the stability of the welding arc. Try this experiment: Watch the volt meter and the ammeter as the welder welds a short bead. As the welder is progressing along the plate, have him slowly pull the gun further and further away from the plate. You will see that the voltage stays nearly constant as the amperage steadily drops the further the gun is pulled from the plate.


My experience is that many welders hold the gun too close to the work, thus the electrode extension is too short. Elongated porosity is often the result. If you note porosity, but there is slag in the porehole, the voltage is too high.

Once you visit the electrode manufacturer's web site to verify the optimum welding parameters, set the machine and watch the welder to verify the proper electrode extension, wire feed speed, and arc voltage is maintained. Don't forget to verify the shielding gas is the same as that recommended by the manufacturer as well.


Best regards - Al

 

[glazetm]

Thanks gtaw

 

[gtaw]

Happy to help.

Best regards - Al

 

[Guest102023]

Trimark is an excellent product, so unless during storage it somehow picked up moisture or contamination on the wire surface, then it is a cleanliness, equipment, or process problem, most of which are covered above.