Stainless
Aluminum
Frequency and Pulse
Wave Forms and amperage
Welding Techniques
100
Decreasing Amperage to allow for a slower travel speed will help prevent carbide precipitation.
False
100
What is the melting point of aluminum?
1200 Degrees
100
What unit is frequency measured in?
Hertz
100
Why is it best to keep the balance control to no more electrode positive than needed?
It will leave excessive etching on the sides of the weld bead that is unnecessary.
100
when fitting up an open root test what can be used to set the appropriate gap to ensure adequate penetration.
TIG wire
Stick rod with the flux broken off
200
What is the rule of thumb when setting amperage to the material thickness when welding Stainless Steel?
1 Amp per thousandth of an inch, then subtract 10%
200
Which filler material is not suitable for welding aluminum Car Radiators (Car radiators tend to exceed temperatures of 150 degrees)
316L
5356
200
A faster pulse rate results in a __________ overall heat input.
Lower
200
An increase in the % on-time control would lead to a(an) __________ in the heat provided by the weld circuit.
Increase
200
For the lay wire technique what would be my appropriate gap measurement and filler rod size
1/8" gap 1/8" wire
3/32" gap 3/32" wire
300
what can be done to remove carbide precipitation from the surface of a stainless weld post weld?
pickling removes the carbide precipitation and promotes a protective passive layer to form
300
How much hotter in degrees Fahrenheit does the aluminum oxide layer on aluminum melt compared to raw aluminum
2400 Degrees
300
What are the main two things that increasing the ac frequency does?
Narrow puddle, Increase Penetration
300
AC Balance Control
300
Which of the following open root techniques is used to get the most root reinforcement?
Back feed
400
Blues and Purples on Stainless steel after welding is a sign of _______ ________. Two word answer
Carbide Precipitation
400
4043 Filler is used on aluminum parts that are going to be anodized
False
400
Why must you have High Frequency continuously when welding on Aluminum?
Because of the A/C sine passing zero every time it changes polarity the arc could go out so the high frequency keeps the arc stable through this part of the wave by raising the voltage to jump accross the zero point at a fast enough speed to never fully stop.
400
By decreasing the background amperage percentage, you will get a ___________ puddle. For example if you amperage was set at 100 amps and you lowered the background percentage from 50% to 30%. One word answer
smaller
narrower
400
If an open root plate test has a gap measured at 1/8" what would be the appropriate rod size for the back feeding technique
3/32
500
What two elements gather at the grain bounderies in the occurance of carbide precipitation?
Carbon and Chromium
500
Why must A/C Polarity be used when welding Aluminum at a molecular level? Do not generalize your answers
A/C uses both polarities in which DCEP has ions which bombard the material surface breaking up the aluminum oxide layer, the DCEN polarity then causes the ions to pull the now loose aluminum oxide off of the plate surface to expose the clean aluminum atoms giving a better fusion surface and cleaner overall weld bead.
500
The pulse feature is inactive during: (Look in reference material)
Upslope and downslope
500
Using the formula: Average weld circuit output = (maximum output X percent on time) + (background output X (1.00 - percent on time))
Calculate the average weld circuit output for a machine with 180 amps maximum current, 40 amps pulse background current and 65% pulse on-time.
(Percent on time needs to be converted to a decimal)
131
500
When welding open root GTAW. Which Techniques is it best to have a land? Name all 4
Lay wire cup Wiggle
Keyhole and dab
Backfeed
Lay wire Step