GTAW On Mild Steel Flashcards
How should you lay the beads when surface welding for buildup work
Blend them together so they form a solid layer of weld metal
Is it necessary (yes or no) to remove the following from the mild steel base metal before welding with GTAW
- millscale
- loose rust
- oil
- varnish
- soapstone markings
- no but is can be done to reduce undercut on the cap pass
- yes
-yes - yes
- no
Identify the following for GTAW on mild steel
Most common electrode type
Electrode preparation shape
Current type
EWTh 2
Conical
DCSP
DCEN
What shielding gas is most often used for GTAW on mild steel
Argon
What size of gas nozzle is recommended for any GTAW application
The smallest nozzle whose lip does not melt in the heat of the arc yet allows good visibility and adequate gas shielding
An appropriate electrode stick out for GTAW
Maintains a gas shield around the electrode and molten weld metal
Advantage and disadvantage of touch start
Adv: DC without high frequency
Disv: may contaminate the electrode
Advantage and disadvantage of high frequency start
Adv: start without contamination
Disv: ceramic nozzles must be used
Advantages and disadvantages of lift start
Adv: no high frequency required
Disv: machine design must be compatible
Name two techniques used for adding filler rod with GTAW
Dip feed
Continuous
Changing the inclination of the electrode holder in relation to the direction of travel
Changes the depth of penetration of the weld
In what positions can you do surface welding with GTAW
All positions
Describe the purpose of tailing out prior to breaking the arc
Prevent cracking in the weld crater
How is the work positioned for a 1F tee joint
Each member at 45 to the horizontal plane
Given the choice what position should you use for the most productive fillet welding
1F