Quote:
Originally posted by Slider79SC
With TIG welding is it better to use a draw method and put the filler in as you go or a push method and put the filler in front?
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Unlike MIG, it's hard to go backwards with TIG. Compare TIG to Oxy/gas welding where the forward angle of the flame is preheating where you are going. MIG goes either way, depending on how hot you want the puddle ("pushing" is hotter; better penetration with the same current).
The new terms for the welding processes are GMAW (MIG) SMAW (shielded metal arc; stick welding) and GTAW (gas tungsten arc). The reason for the change is that the "I" in MIG and TIG stood for "inert" (gas). Sometimes the gasses used are not inert, such as C02. The "semi-inert" gases used for some specialized welding processes can also contain O2, nitrogen and hydrogen. In the basic cases, the inert gasses are shielding these types of gases from contaminating the weld. However, in controlled amounts, the non inerts help the weld quality.
The wire feed welding process is almost the same as the stick process with the electrode moving toward the weld and being consumed as a filler metal. However, the processes differ in the type of power used. The stick is mostly a constant current (CC) process where the voltage changes with the resistance or distance of the arc. The GMAW uses a constant voltage (CV) with the current flowing higher of lower depending, again, of the distance of the arc. A wire feed without gas is simply a flux core wire (FCAW) and works, once more, like the SMAW process with the flux providing the shielding gas as it is heated in the arc. You would reverse the polarity (another subject) for FCAW vs. GMAW.
GTAW uses the same CC process as the SMAW, but there are a lot of controls to adjust for the different metals. TIG or TAG (sub processes of GTAW; tungsten
active gas vs. inert) can use AC or DC and positive or negative electrode. the AC frequency can be very high for a smooth arc, virtually uninterrupted. That would be for aluminum. DCEN (direct current-electrode negative) is for steel. The ionized electrons are flowing to the work in this process keeping the arc stable.
I’m writing all of this to continue to commit the processes to memory and I know it's more than most care to know. I was in welding school last year and had this all down pat. But, like anything else, if you don’t keep up on it, the knowledge starts to fade. And I only know the tip of the iceberg in terms complete knowledge of the science. But, I did write this, not cut and paste.
Best thing I ever did was to at least learn something about what I had been doing hap hazzardly for years.