Welding Multiple Choice Questions and Answers

21. The welding machine, which is used to convert AC welding supply to DC welding supply is

1. Motor generator set
2. Engine generator set
3. Rectifier set
4. Welding transformer

22. The correct flame for preheating before cutting is

1. oxidizing flame
2. neutral flame
3. carburising flame
4. slightly carburizing flame

23. Neutral flame in gas welding contains

1. oxygen & Actylene in equal proportion
2. More oxygen than Acetylene
3. less oxygen than Acetylene
4. None of the above

24. In DC welding heat distribution is possible between electrode and the base metal due to the change of polarity. The distribution of heat is

1. Psitive 2/3 and negative 1 /3
2. Positive 1 /3 and negative 2/3
3. Positive 3/4 and negative 1/4
4. Positive 1/4 and negative 3/4

25. The correct colours for oxygen and acetylene hoses are:

1. Red for oxygen and blue for acetylene
2. Black for oxygen and red for acetylene
3. Black for oxygen and maroon for acetylene
4. Red for oxygen and maroon for acetylene

26. Which one of the following is the type of transformer used in arc welding?

1. Step down
2. Step up
3. One-to-one
4. Capable of increasing supply voltage

27. Cast iron contains two elements, which make it difficult to cut it by gas cutting. What are these elements?

1. Sulphur and phosphorous
2. Silicon and graphite
3. Graphite and phosphorous
4. Silicon and sulphur

28. The function of the central hole in the tip of the cutting blowpipe is

1. Supply oxygen for preheating
2. Supply acetylene for preheating
3. Supply oxygen for cutting
4. Supply acetylene for cutting

29. In gas cutting, if too little cutting oxygen is supplied

1. the metal will be cooled down
2. the kerf will be narrow
3. the kerf will be wide
4. the metal will fail to cut completely

30. The size of the cutting nozzle used in oxy-acetylene cutting process depends mainly on

1. thickness of metal to be cut
2. purity of oxygen
3. duration of cut
4. type of cutting blowpipe