Line D Flashcards
What melts the surfaces of the joint when performing shielded metal arc welding (SMAW)?
1) The flow of current
2) The heat of the arc
3) Contact of the electrode with work
4) Contact of the ground clamp with work
2) The heat of the arc
How is the shielding established in SMAW?
1) By the amount of current being used
2) By the solidified slag covering the weld
3) By the metal droplets crossing into the joint
4) By the protective gas from the electrode coating
4) By the protective gas from the electrode coating
Who is responsible to ensure that workers are trained in the care and use of protective equipment when welding?
1) The employer
2) The individual doing the work
3) The engineer
4) The supervisor overseeing the work
1) The employer
What is the suggested lens shade number for protection during SMAW at 160-250 amps?
1) Shade 7
2) Shade 8
3) Shade 10
4) Shade 12
4) Shade 12
How is electrical current measured?
1) In voltage
2) In amperes
3) In polarity
4) In resistance
2) in amperes
What is one advantage of welding on alternating current (AC)?
1) The risk of electric shock is lower than on direct current (DC)
2) There is a wider range of electrodes available
3) The arc is stable and smooth
4) Arc blow is rarely a problem
4) Arc blow is rarely a problem
What must be done to change from welding on direct current electrode positive (DCEP) to welding on direct current electrode negative (DCEN)?
1) By using a polarity switch or by reconnecting the cables
2) By relocating the ground clamp or changing electrodes
3) By adjusting the amperage dial or by reconnecting the cables
4) By using a polarity switch or adjusting the amperage dial
1) By using a polarity switch or by reconnecting the cables
What condition exists when the power source is, but no arc has been struck yet?
1) Arc voltage
2) Open circuit voltage
3) Closed circuit voltage
4) Short circuit voltage
2) Open Circuit Voltage
What happens to the relationship between current and voltage if arc length is increased?
1) Both current and arc voltage will increase
2) Arc voltage is reduced while current is increased
3) Current is reduced while arc voltage is increased
4) Both current and arc voltage will decrease
3) Current is reduced while arc voltage is increased
What type of welding power source generates only alternating current (AC)?
1) Engine drive
2) Inverter
3) Rectifier
4) Transformer
4) Transformer
What must be done to alternating current (AC) to change it to direct current (DC)?
1) Use a transformer to step up AC output from an inverter
2) Use diodes to rectify AC output from a transformer
3) Use a thyrister to rectify DC output from a transformer
4) Use an SCR to alternate DC output from a rectifier
2) Use diodes to rectify AC output from a transformer
What must be done to minimize the loss of power and prevent overheating of welding cables when shielded metal arc welding?
1) consider the amount of current being used and distance from the work
2) conder the type of current and available utility voltage for the power source
3) use the largest available size cable and coil up access cable
4) use the smallest available cable and use as short a length as possible
1) consider the amount of current being used and distance from the work
What cable size should be used when welding with a 300 amp power source?
Look at table
1/0
How can the flux coating on a welding electrode alter the chemical composition of the weld?
1) With the addition of iron and alloy powders in the flux coating
2) By forming a solidified slag covering over the weld
3) By establishing an ionized gas shielding around the arc
4) With an increased arc length and slower travel speed
1) With the addition of iron and alloy powders in the flux coating
Which material, when incorporated into the flux coating of an electrode, will increase weld metal penetration into the base material?
1) Potassium
2) Rutile
3) Fluorspar
4) Cellulose
4) Cellulose