21. Residual stresses caused due to welding can be decreased by …….
(a) Allowing parts to move freely during welding
(b) Using “back step” sequence
(c) Post weld heat treatment
(d) Both (a) and (c}
22. Gas welding torch should be lighted only with …….cevee
(a) Matches
(b) Cigarette lighter
(c) Striker
(d) Welding arc
23. ……….. can be cut with oxy-acetylene cutting torch.
(a) Stainless steel
(b) Carbon steel (d) Welding arc
(c) Aluminium
(d) Copper – nickel alloy
24. Which oxy-acetylene flame has an excess of flue gas?
(a) Oxidizing
(b) Neutral
(c) Carburizing
(d) None of these
25. An arc welding equipment should never be operated while
(a) Standing on wet floor
(b) In poorly lighted area
(c) Someone is standing nearby
(d) In a confined space with proper ventilation
26. What should never be used on gas cylinders, regulators and hoses?
(a) Wrenches
(b) Teflon tapes
(c) Leak detectors
(d) oil
27. Which defect is caused by gas entrapment in arc welding process?
(a) Crack
(b) Porosity
(c) Lack of fusion
(d) Slag inclusion
28. A.W.S. code of electrode starts with the letter E followed by a 4 digit number. What does the 3″ digit represent?
(a) Polarity
(b) Welding position
(c) Type of flux coating
(d) Tensile strength of the weldment
29. What is the storage medium used to store acetylene gas in the cylinder at high pressure?
(a) Water
(b) Acetone
(c) Kerosene oil
(d) Petroleum jelly
30. Which one of the following is a temporary joint?
(a) Welded joint
(b) Riveted joint
(c) Soldered joint
(d) Press fit joint