GMAW Flashcards
What is a flow meter?
A device that regulates the flow of shielding gas in Cubic Feet Per Hour rather than pressure. PG 171
What is the difference between a flow meter and a regulator?
A regulator reduces high storage pressure to pounds per square inch, a flow meter reduces high storage pressure to Cubic Feet Per Hour (CFH)
Why do different shielding gases require different scales in the flow meter?
Different density of shielding gas cause the need for different scales. Pg. 172
What is the purpose of the purge switch?
To purge the lines without running wire which would be electrically live. Pg. 184
What is the purpose of the jog or inch switch?
To run wire through the wire feeder and GMAW gun without needlessly wasting gas. Pg. 184
When is Helium used for GMAW?
Helium is used when high heat input is required, like when welding aluminum particularly thick sections. Pg. 184
What % of argon is needed for spray transfer?
A shielding gas mixture with a minimum of 90% argon is required Pg. 184
What does the E in ER70S6 stand for?
Electrode Pg. 189
What does the R in ER70S6 stand for?
Rod Pg. 189
What does the 70 in ER70S6 Stand for?
Tensile strength 70 000PSI Pg. 189
What does the S in ER70S6 stand for?
Solid, this means the welding wire is solid steel Pg. 189
What does the 6 in ER70S6 stand for?
Chemical composition, in this case the six means higher amounts of manganese and silicon .Pg 189
For every pound of solid electrode wire, how much ends up becoming deposited weld metal.
92% to 98% waste comes from changing the role and trimming the wire end between welds. Pg.233
What are the two ways to deposit metal?
through the arc and around the arc, spray or pulse spray is through the arc while short circuit and globular is around the arc. Pg. 236
What are the three types of metal transfer?
Short Circuit, Globular, & Spray Pg. 236
What are the characteristics of C02 shielding gas?
Higher thermal conductivity than argon,CO2 heavier than argon and shields well, wide beads with deep penetration, no undercutting, a great deal of spatter occurs,
What are the characteristics of Argon shielding gas?
Deep penetration, a narrow bead, and almost no spatter.
What are the characteristics of Helium shielding gas?
It has a high conducting ability, a shallow fluid puddle, more spatter.
What part of the GMAW gun passes the electricity to the welding wire?
The contact tip or tube
Which positions are recommended for spray transfer?
Flat and some horizontal positions
Which positions are recommended for globular transfer?
Flat and some horizontal positions
Which positions are recommended for short circuit transfer?
All positions
What type of gun is used for welding aluminum with GMAW?
a spool gun or pull type gun Pg.187
Which welding direction attains the deepest penetration?
Backhand
Which welding method allows the heat to progress one direction while the weld is completed in the other direction?
Back stepping
What is electrode extension?
Is the amount that the end of the electrode wire sticks out beyond the end of the contact tube. Pg. 252
How does short circuit transfer deposit metal?
The arc is not present when the wire touches the molten weld pool. The surface tension pulls the molten metal from the end of the wire into the pool. The pinch force squeezes the electrode helping deposit the metal. The arc than restarts the wire makes contact and the process starts again.
How does globular transfer deposit metal?
The electric arc produces a large globule on the end of the wire and gravity forces it to drop into the weld puddle due to its own weight.
How does spray transfer deposit metal?
Spray transfer deposits through the arc in fine droplets as the pinch force is so great to squeeze the metal off the tip of the wire in fine droplets.
what are the two way we can shield the puddle when FCAW?
The two ways we can shield FCAW is with the interior flux of the wire and a second gas shield supplied by pressurized gas cylinders. Pg. 190
What part of the GMAW gun do you fasten the contact tip to?
The Diffuser
