BL electric arc welding.txt

    • author "me"
    • tags ""
    • description "88l20f05"
    • fileName "electric arc welding"
    • freezingBlueDBID -1.0
    • how often should a direct current arc welding machine be inspected
    • every 3 months
  1. how do you clean a direct current arc welding machine and how often
    clean dry compressed air and every 3 months
  2. in the direct current arc welding machine the contacts of the motor starter switches and the rheostat should be cleaned and replaced if necessary when?
    Every year
  3. how often do you check the bearings on a direct current arc welding machine
    twice a year
  4. what is used to loosen scale oxides and slag off the weld
    chipping hammer
  5. what is a wire brush used for in welding
    clean each weld bead before further welding
  6. If a electrode has been in moisture then you weld with it what could happen.
    Excessive splattering, lead to the formation of cracks in the welded area
  7. What does moisture do to a electrodes
    Destroys the desirable characteristics of the coating
  8. Electrodes expose to damp there for more than 2 or 3 hours should be dried by heating in a suitable oven. How long? What temp? and what do you do when you take them out?
    • 2 hours
    • 500 degrees fahrenheit
    • place in moisture proof container
  9. can you use a electrode if the core wire is exposed
  10. What kind of weld does a DC straight polarity produce
    Shallow wide weld
  11. what kind of weld does a d c reverse polar produce
    deep penetrating narrow weld
  12. all metals fall into 2 categories what are they
    • Ferrous
    • Nonferrous
  13. What categories does aluminum, copper,magnesium and titanium alloys fall in
    Nonferrous metals
  14. What category does metals that contain iron
    Ferrous metals
  15. What does the electrode covering do or how does it work
    Shield the molten merely from the atmosphere as it is transferred across the arc and improves smoothness stability of the arc
  16. Unused electrode stubs and splatter account for about what? Percent consumed electrode
    44 percent
  17. What is the principal force which accounts for the transfer of filler metal in flat position welding
  18. When not welding in a flat position you should use what kind of electrode
    Smaller electrode must be used to avoid excessive loss of weld metal and slag
  19. temperatures can get as hot as what in shielded metal arc welding
    9000 degrees
  20. What are the 3 types of free flight metal transfer in a welding arc.
    • Projected (spray)
    • Repelled (by Co2)
    • Gravitational (globular)
  21. what is the force which keeps the filler metal and slag globules in contact with molten base or weld metal in the crater is known as ?
    Surface tension
  22. What is shielded metal arc welding also known as.
    • Metallic arc
    • Manual metal arc
    • Stick election welding
Card Set
BL electric arc welding.txt
BL electric arc welding.txt