Question & Answer On WELDING & FABRICATION | MCQ

WELDING & FABRICATION

1. The welding process using an electric arc developed between a flux-covered electrode and the metal being welded is known as.

• flux cored arc welding

• resistance spot welding

• shielded metal arc welding

• submerged arc welding

2. Flux is used when soldering, in order to.

• decrease the melting point of the solder

• make the solder 'flow'

• ensure proper tinning

• clean the joint area

3. Why is a chemical covering applied to a welding stick electrode, rather than using a bare electrode?

• Protect the welder from electric shock.

• Prevent arc blow.

• Shield the arc during the welding process to prevent oxidation.

• Stabilize the electron emission rate and produce uniform temperatures in the heat-affected zone

4. Which of the statements is incorrect with regard to creep in metal components:

• Creep is the slow continuous plastic deformation of metals under a constant load at elevated temperatures

• Creep properties are determined experimentally, are expensive and prolonged over time

• Creep properties are essential in equipment & systems operating in extremely low temperature systems.

• Creep properties are determined experimentally, are expensive and prolonged over time

5. Mechanical properties of steel & cast iron are dependent upon % of C, proportion of presence of phase & grain size. Which of the statements is incorrect in respect of the allotropic forms of iron & carbon?

• Ferrite is soft & ductile

• Pearlite shows poor strength

• Cementite is weakest of phases

• All steels consist of austenite after primary crystallisation

6. You should never watch the arc generated during electric arc welder with the naked eye because.

• serious flash burns will result

• arc blow will burn your face

• the fumes are highly toxic

• slag and metal splatter will get in your eyes

7. An acetylene pressure regulator should never be adjusted to maintain pressures exceeding 103.4 kPa, because.

• the relief valve will lift

• the fusible plug will blowout

• rapid depletion of acetylene is hazardous

• this gas become extremely unstable under this condition

8. Soldering flux aids the soldering process by.

• softening the metals

• fusing the metals

• removing oxides

• hardening the metals

9. Flux is used when soldering, in order to.

• decrease the melting point of the solder

• decrease the surface tension of the solder

• ensure proper tinning

• control the soldering iron temperature

10. Which statement describes the function of the filler material used in acetylene cylinders?

• It reduces the danger of explosion.

• It chemically reacts with acetone to produce acetylene.

• It neutralizes the gas to render it harmless.

• It is fire resistant and reduces fire hazards

11. Setting up a welding job, where the work is the positive pole and the electrode is the negative pole for the arc, is known as a/an.

• straight polarity welding circuit

• inert-arc welding circuit

• shielded-arc welding circuit

• reverse polarity welding circuit

12. In inert gas metal arc welding

• Argon is used for welding thin materials and helium is used for welding thick materials

• Both Agon and helium are used for thin materials

• Both Agon and helium are used for thick materials

• all of them

13. Mechanical properties of steel & cast iron are dependent upon % of C, hence:

• Hardness decreases with increasing % of C

• Ductility & impact strength decreases with increasing % of C

• Tensile strength & yield strength decreases with % of C

• All cast irons consist of pearlite & primary crystals of excess austenite (hypereutectoid CI) or cementite (hypereutectoid CI).

14. Solder is an alloy of.

• tin and lead

• beryllium and antimony

• copper and lead

• silicon and selenium

15. Setting up a welding job, where the work is the positive pole and the electrode is the negative pole for the arc, is known as a/an.

• straight polarity welding circuit

• inert-arc welding circuit

• shielded-arc welding circuit

• reverse polarity welding circuit

16. A hazard associated with electric arc welding is.

• the effects of radiation from the arc

• flying sparks

• electric shock

• all of the above

17. Which of the statements is incorrect with regard to Stainless steel:

• When 11.5% or more chromium is added to iron, a fine film of chromium oxide forms spontaneously on the surfaces exposed to air.

• The film acts as a barrier to retard further oxidation, rust or corrosion.

• Stainless steel is the ideal material for use in seawater systems.

• Ferritic Stainless Steels are magnetic and have good ductility

18. In order to minimize distortion in a weldment due to shrinkage, you should.

• use intermittent welds rather than continuous welds wherever possible

• make fewer passes with large electrodes as opposed to many passes with small electrodes

• use restraining forces such as clamps, jigs, and fixtures

• all of them

19. Which of the following practices is considered to be safe for the handling and use of compressed gas cylinders?

• Using oxygen as a substitute for compressed air for pneumatic tools.

• Routinely greasing or lubricating the valves on oxygen cylinders.

• The storage of the cylinders in a well ventilated compartment.

• Cracking the valve on a hydrogen cylinder to clear dust and dirt.

20. Tinning a soldering iron will.

• prevent the tip from overheating

• protect the tip from scratches

• add extra weight to the tip

• prevent tip oxidation when heated

21. You should never watch the arc generated during electric arc welding with the naked eye because.

• serious flash burns will result

• arc blow will burn your face

• the fumes are highly toxic

• slag and metal splatter will get in your eye

22. A hazard associated with electric arc welding is.

• the effects of radiation from the arc

• flying sparks

• electric shock

• all of them

23. Which statement describes the function of the filler material used in acetylene cylinders?

• It reduces the danger of explosion.

• It chemically reacts with acetone to produce acetylene.

• It neutralizes the gas to render it harmless.

• It is fire resistant and reduces fire hazards.

24. Which of the statements is incorrect with regard to pipes used in marine systems.

• Nominal pressure is the maximum pressure which is permitted in the pipe at a defined temperature of the flow medium.

• Nominal diameter - is the linear dimension to which all mating parts of the system should conform to ensure the designated value of flow.

• Class I pipes withstand the lowest temperature & pressure, while Class III withstand the highest values.

• Pipe Schedules are designations of pipe wall thickness as given in any appropriate National Standard. Schedule 40 and Schedule 80, refer to up to maximum wall thickness of 9.5 mm & 12.5 mm, respectively.

25. A hazard associated with electric arc welding is.

• the effects of radiation from the arc

• flying sparks

• electric shock

• all of them

26. Oxygen and acetylene cylinders should always be stored.

• upright with the cylinder caps screwed on

• horizontal with the cylinder caps screwed on

• upright with the cylinder caps off

• horizontal with the cylinder caps off

27. Why is a chemical covering applied to a welding stick electrode, rather than using a bare electrode?

• Protect the welder from electric shock.

• Prevent arc blow.

• Shield the arc during the welding process to prevent oxidation.

• Stabilize the electron emission rate and produce uniform temperatures in the heat affected zone.

28. Which of the statements is incorrect with regard to pipes used in marine systems.

• Nominal pressure is the maximum pressure which is permitted in the pipe at a defined temperature of the flow medium.

• Nominal diameter - is the linear dimension to which all mating parts of the system should conform to ensure the designated value of flow.

• Class I pipes withstand the lowest temperature & pressure, while Class III withstand the highest values.

• Pipe Schedules are designations of pipe wall thickness as given in any appropriate National Standard. Schedule 40 and Schedule 80, refer to up to maximum wall thickness of 9.5 mm & 12.5 mm, respectively.

29. Which of the statements is incorrect with regard to materials for marine equipment:

• The yield point is the first stress in a material, less than the maximum obtainable stress, at which an increase in strain occurs without an increase in stress.

• Young's modulus characterizes the rigidity of material, i.e. its resistance to elastic deformation in tension.

• Tensile Strength is defined as the stress that occurs at max load that specimen can withstand without failure.

• Ductility indices are determined to indicate the ability of metal to deform under impact without failure.

30. Which of the following practices is considered to be safe for the handling and use of compressed gas cylinders?

• Using oxygen as a substitute for compressed air for pneumatic tools.

• Routinely greasing or lubricating the valves on oxygen cylinders.

• The storage of the cylinders in a well ventilated compartment.

• Cracking the valve on a hydrogen cylinder to clear dust and dirt.

31. Which of the statements is incorrect with regard to fatigue failure in metal components:

• The failure of the metal component occurs under repeated pulsating or reversing stresses.

• The failure occurs at stress levels which are below the yield point.

• The resistance to fatigue failure is characterized by its fatigue or endurance limit.

• None of them

32. While carrying out electric arc welding, there is always the danger of.

• developing burns to the retina of the eye

• fire

• electric shock

• all of them

33. While carrying out electric arc welding, there is always the danger of.

• developing burns to the retina of the eye

• fire

• electric shock

• all of the above

34. Oxygen and acetylene cylinders should always be stored.

• upright with the cylinder caps screwed on

• horizontal with the cylinder caps screwed on

• upright with the cylinder caps off

• horizontal with the cylinder caps off

35. While carrying out electric arc welding, there is always the danger of.

• developing burns to the retina of the eye

• fire

• electric shock

• all of them

36. Which of the statements is incorrect with regard to materials for marine equipment:

• Hypoeutectoid steel occurs up to 8% C.

• Hypoeutectoid cast iron occurs between 2 & 4.3% C

• Hypereutectoid steel occurs between 0.8 & 2% C.

• Hypereutectoid cast iron occurs between 4.3 & 6.67% C.

37. An acetylene pressure regulator should never be adjusted to maintain pressures exceeding 103.4 kPa, because.

• the relief valve will lift

• the fusible plug will blowout

• rapid depletion of acetylene is hazardous

• this gas becomes extremely unstable under this condition

38. Mechanical properties of steel & cast iron are dependent upon % of C, proportion of presence of phase & grain size. Which of the statements is incorrect in respect of the allotropic forms of iron & carbon?

• Ferrite is soft & ductile

• Pearlite shows poor strength

• Cementite is weakest of phases

• All steels consist of austenite after primary crystallisation

39. Solder used for joining metal surfaces should have a .

• fusing point much higher than that of the metals being joined

• melting point lower than that of the metals being joined

• coating of Borax flux to raise the melting point

• composition of lead and tin if the solder is the 'hard' type