MCQ’s On Welding and Related Processes
Q. Which of the following is not included in weldability?
A. Ability of mechanical soundness
B. Serviceability of joint
C. Strain relieving brittleness
D. Metallurgical compatibility of metal
.
.Answer: C
Explanation: Process For the making of good fabricated composition of a structure, metal with good weldability gets readily welded. Weldability includes the ability of the metal or the alloy to be having soundness in its mechanical properties, metallurgical compatibility of metal and serviceability of joint.
Q. Which effect is not seen in alloys on weldability?
A. Control of ductile-malleable transformation temperature
B. Provision for oxidation to molten metal
C. Reduction in segregation
D. Grain refinement
.
.Answer: B
Explanation: Process On weldability, there are some effects seen in the alloying elements. Some of them are Control of ductile-malleable transformation temperature, Reduction in segregation, Grain refinement and provision for deoxidation to the molten metal.
Q. On which of the following factor, does weldability not depend?
A. Boiling point
B. Melting point
C. Thermal expansion
D. Thermal conductivity
.
.Answer: A
Explanation: Process Weldability is dependent on five factors of the metal or alloying element. The factors being, melting point, thermal expansion, thermal conductivity, surface condition and change in the microstructure.
Q. Which of the following is not a way of correcting the metal which does not have good weldability properties?
A. Procedure of welding
B. Provision of fluxing material
C. Provision of filler material
D. Procedure of adding filler materials
.
..Answer: D
Explanation: Process When a particular metal or an alloy does not have desirable welding characteristics, then it can be corrected by proper fluxing material, correct filler material and a perfect welding procedure.
Q. What does HAZ stand for?
A. Helium Aerated Zone
B. Heated Area Zone
C. Heat Affected Zone
D. Heat Allowed Zone
.
.Answer: C
Explanation: Process HAZ stands for Heat Affected Zone. This zone is generally the base of the metal or a thermoplastic material. This zone is not melted but the properties are altered by the welding Process.
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Q. With an increase in the heat input of arc welding method, how does it affect the welding speed?
A. Increases
B. Decreases
C. Remains same
D. No relation
.
.Answer: B
Explanation: Process In arc welding Processes, for calculating the efficiency, we use the formula for heat input. According to the formula, heat input is inversely related to the speed of welding, that is, with an increase in heat input, the welding speed decreases.
Q. With an increase in the heat input of arc welding method, how does it affect the voltage applied?
A. Increases
B. Decreases
C. Remains same
D. No relation
.
.Answer: A
Explanation: Process None.
Q. With an increase in the heat input of arc welding method, how does it affect the required current?
A. Increases
B. Decreases
C. Remains same
D. No relation
.
.Answer: A
Explanation: Process None.
Q. In fusion welding, welded pieces are kept together under pressure.
A. True
B. False
.
Q. Materials having high thermal conductivity are difficult to melt.
A. True
B. False
.
.Answer: A
Explanation: Process Materials that have a medium melting point are considered to be welded easily and those materials which have their thermal conductivity very high are the toughest to be melted.
Q. Which of the following could be considered as a related Process?
A. Explosive
B. Oxy-Hydrogen welding
C. Oxy-Acetylene cutting
D. Electron-beam
.
.Answer: C
Explanation: Process Among the following, oxy-acetylene cutting is considered as a related Process. Explosive is a type of solid state welding. Electron-beam is a type of newer welding and oxy-hydrogen welding is a form of gas welding.
Q. A liquid phase has to be used in cold welding.
A. True
B. False
.
.Answer: B
Explanation: Process It is hot welding that a liquid or a molten state is used for the joining of two pieces of metal. But in cold welding, there is no use of a liquid phase, that is, joining is done without using heat.
Q. Which of the following is not a type of arc welding?
A. Plasma
B. Electro-slag
C. Submerged
D. Air-acetylene
.
..Answer: D
Explanation: Process Among the following, plasma arc, electro-slag and submerged arc are few of the types of arc welding. Air-acetylene is one of the forms of gas welding Processes.
Q. Which of the following is not a type of resistance welding?
A. Seam
B. Projection
C. Electro-slag
D. Spot
.
.Answer: C
Explanation: Process Among the following, seam, projection and spot are few of the types of resistance welding. Electro-slag is one of the forms of gas welding Processes.
Q. Which of the following materials are not suited for cold welding?
A. Brass
B. Steel
C. Silver
D. Gold
.
.Answer: B
Explanation: Process Cold welding Process is not very suitable for alloys like steel, the reason being, cold welding cannot take place excellently in ferrous materials. Steel contains high amount of iron, hence it cannot be cold welded.
Q. What is the cross-sectional shape of a thermoplastic welding rod?
A. Triangular
B. Hexagonal
C. Square
D. Pentagonal
.
.Answer: A
Explanation: Process A welding rod or a thermoplastic welding rod is used mainly in plastic welding. The rod should not be very porous or it may catch voids. This rod has a cross sectional shape triangular or circular.
Q. Which of the following is not a type of related Processes?
A. Soldering
B. Percussion
C. Brazing
D. Hard-pressing
.
.Answer: B
Explanation: Process Among the following, soldering, pressing and hard-pressing are few of the types of related Processes. Percussion is one of the forms of resistance welding Processes.
Q. Laser is classified under newer beam.
A. True
B. False
.
.Answer: A
Explanation: Process There are various types of welding Processes, one of them is a newer welding Process. Under this, there are two types, one is electron-beam and another is the use of laser.
Q. Which of the following is not a type of solid state welding?
A. Projection
B. Ultrasonic
C. Friction
D. Diffusion
.
.Answer: A
Explanation: Process Among the following, ultrasonic, friction and diffusion are a few of the types of related Processes. Percussion is one of the forms of resistance welding Processes.
Q. Slag used in fusion welding has nitrogen.
A. True
B. False
.
.Answer: A
Explanation: Process Slags used in welding are generally a combination of silica materials and some carbonate compounds. In fusion welding, some amount of bead control has to be done, which is done by the slags, for this purpose, to improve its performance, microelements like nitrogen are added.
Q. In which run weld, in ordinary steels, the grain refinement takes place?
A. First
B. Second
C. Third
D. Fourth
.
.Answer: B
Explanation: Process A multi run Process causes a good amount of grain refinement. With every proceeding run weld, it normalizes its previous run. In ordinary steels, grain refinement takes place in the second run.
Q. What is the minimum strength of mild steel arc welds on addition of microelements in the slag?
A. 43 kgf/mm2
B. 39 kgf/mm2
C. 45kgf/mm2
D. 48 kgf/mm2
.
.Answer: A
Explanation: Process When there is an addition of some microelements in the slag along with a few materials being present which are not metals, there is an increase in the strength of the mild steel arc weld. The minimum amount of strength goes up to 43 kgf/mm2, which is 430 N/mmQ.
Q. Which of the following is affected by weld contour?
A. Fatigue
B. Creep
C. High pressure property
D. Low pressure property
.
.Answer: A
Explanation: Process The contour present on the welds form notches. The contours in the form of notches then affect the low temperature properties of the structure and also the fatigue properties.
Q. Thermite contains which metal?
A. Zinc
B. Copper
C. Aluminium
D. Manganese
.
.Answer: C
Explanation: Process The reaction that takes place in between compounds and elements is known welding with solid reactants. These reaction are exothermic, that is give out heat as a product. Thermit reaction is a common example for this, which is mixture of aluminium and rust.
Q. Which of the following property is considered for controlling the porosity of the metal?
A. Solid solubility
B. Liquid solubility
C. Gas solubility
D. Flame solubility
.
.Answer: C
Explanation: Process The amount of solubility of gas in liquid or solid welded metals is considered to be an essential criteria for the control of porosity of the weld. The gas reactions which occur, then regulate porosity.
Q. Slag used in fusion welding contains manganese.
A. True
B. False
.
.Answer: A
Explanation: Process Slags used in welding are generally a combination of silica materials and some carbonate compounds. In fusion welding, some amount of bead control has to be done, which is done by the slags, for this purpose, to improve its performance, microelements like manganese are added.
Q. Which of the following property is responsible for weld metal cracking?
A. Stress
B. Strain
C. Temperature conditions
D. Pressure conditions
.
.Answer: A
Explanation: Process The stresses which get developed in welding during shrinkage are of importance. These stresses are considered to be an important factor which are responsible for the cracking that occurs in metal welds.
Q. A thermit reaction produces heat up to what temperature?
A. 4800°F
B. 4000°F
C. 5600°F
D. 5300°F
.
.Answer: B
Explanation: Process None.
Q. Slag used in fusion welding has nitrogen.
A. True
B. False
.
.Answer: A
Explanation: Process Slags used in welding are generally a combination of silica materials and some carbonate compounds. In fusion welding, some amount of bead control has to be done, which is done by the slags, for this purpose, to improve its performance, microelements like nitrogen are added.
Q. Which of the following is affected by weld contour?
A. Fatigue
B. Creep
C. High pressure property
D. Low pressure property
.
.Answer: A
Explanation: Process The contour present on the welds form notches. The contours in the form of notches then affect the low temperature properties of the structure and also the fatigue properties.
Q. Thermite contains which metal?
A. Zinc
B. Copper
C. Aluminium
D. Manganese
.
.Answer: C
Explanation: Process The reaction that takes place in between compounds and elements is known welding with solid reactants. These reaction are exothermic, that is give out heat as a product. Thermit reaction is a common example for this, which is mixture of aluminium and rust.
Q. Which of the following property is considered for controlling the porosity of the metal?
A. Solid solubility
B. Liquid solubility
C. Gas solubility
D. Flame solubility
.
.Answer: C
Explanation: Process The amount of solubility of gas in liquid or solid welded metals is considered to be an essential criteria for the control of porosity of the weld. The gas reactions which occur, then regulate porosity.
Q. Slag used in fusion welding contains manganese.
A. True
B. False
.
.Answer: A
Explanation: Process Slags used in welding are generally a combination of silica materials and some carbonate compounds. In fusion welding, some amount of bead control has to be done, which is done by the slags, for this purpose, to improve its performance, microelements like manganese are added.
Q. Which of the following property is responsible for weld metal cracking?
A. Stress
B. Strain
C. Temperature conditions
D. Pressure conditions
.
.Answer: A
Explanation: Process The stresses which get developed in welding during shrinkage are of importance. These stresses are considered to be an important factor which are responsible for the cracking that occurs in metal welds.
Q. A thermit reaction produces heat up to what temperature?
A. 4800°F
B. 4000°F
C. 5600°F
D. 5300°F
.
.Answer: B
Explanation: Process None.
Q. In which run weld, in ordinary steels, the grain refinement takes place?
A. First
B. Second
C. Third
D. Fourth
.
.Answer: B
Explanation: Process A multi run Process causes a good amount of grain refinement. With every proceeding run weld, it normalizes its previous run. In ordinary steels, grain refinement takes place in the second run.
Q. Which of the following types of fuel gas is commonly used in gas welding?
A. Biogas
B. Coal gas
C. Acetylene
D. Methane
.
.Answer: C
Explanation: Process Gas welding is usually referred as oxy welding or oxy-fuel welding which is a Process of joining metallic materials by application of heat produced by the gas flame. In gas welding, acetylene is commonly used as fuel gas which mixed with proper proportion of oxygen in a mixing chamber of welding torch. Gas welding can produce a hot flame of temperature about 3000-3500 ⁰C.
Q. In gas welding, the joint can be made even much stronger than the original.
A. True
B. False
.
.Answer: A
Explanation: Process In gas welding, various metals like cast iron, steel, aluminium, copper etc. can be used for joining operation. First they brought into a molten state and then a fusion is taking place between two pieces of metal in such a way that the point of fusion closely approaches the strength of the metal fused. In this Process, the union or joint can be made even much stronger than the original.
Q. Acetylene is a hydrocarbon which molecule is made up of two carbon atoms and four hydrogen atoms.
A. True
B. False
.
.Answer: B
Explanation: Process In gas welding, acetylene is used as a fuel gas which is a hydrocarbon like other as propane, methane etc. However, it generally differs from those hydrocarbons in a manner that its molecule is made up of two carbon atoms and two hydrogen atoms. And the carbon atoms are joined with hydrogen atoms by making a triple bond.
Q. Acetylene is a blue color gas which mixed with oxygen to produce a hot flame.
A. True
B. False
.
.Answer: B
Explanation: Process In gas welding, acetylene is basically a colorless gas with a very distinctive odour and highly combustible when it is mixed with oxygen. Acetylene gas is formed by mixing the calcium carbide with water and then it is composed, which forms a compound of carbon and hydrogen having the chemical formula C2HQ.
Q. Gas welding is mainly suited for welding of thin sheets, small diameter pipes and tubes.
A. True
B. False
.
.Answer: A
Explanation: Process Gas welding Process is mainly suited for the welding of a thin sheet, tubes, and small diameter pipe because it cannot provide very high temperature as compared to that provided by the electric arc welding. This method of joining is also used for repairing work, maintenance and in body shops.
Q. Acetylene is a non-toxic gas which can be kept or stored in a cylinder at any pressure.
A. True
B. False
.
.Answer: B
Explanation: Process In gas welding, acetylene is used as a fuel gas which produces hot flame when it is mixed with oxygen. Acetylene may be non-toxic gas, but if it is stored in a cylinder at more than the pressure of 2 bar, then the acetylene becomes self explosive, that’s why the pressure of stored acetylene should be maintained with great care.
Q. Single stage gas regulator cannot be used in cold weather for regulating the acetylene or oxygen gas.
A. True
B. False
.
.Answer: A
Explanation: Process Single stage converter is used to reduce the pressure from the cylinder pressure to the welding pressure, which can take place in a single stage. However, it tends to freeze in cold weather. This is because an abrupt expansion and resulting drop in initial pressure makes rapid cooling of the gas and may cause ice formation in the presence of moisture.
Q. In gas welding, the hoses are mainly used for making the connection between gas torch and regulators.
A. True
B. False
.
.Answer: A
Explanation: Process In gas welding, the hoses are mainly used for making connections between the gas torch and the regulators, which should be made strong, light and flexible enough to make torch movements smooth. In general, welding hose can be of two types that are twin welding hose and double welding hose.
Q. A flashback is a condition in gas welding, when the pure methane gas is used as fuel gas instead of acetylene.
A. True
B. False
.
.Answer: B
Explanation: Process In gas welding, a flashback is a condition in which the flame burns inside the gas torch. Flashback is generally caused by improper mixing of gases, which further increases the rate of flame propagation to high extent that the flame goes back to the mixing chamber. If it is not stopped, the flame may burn the mixture and may travel back into the cylinder.
Q. A welding torch is mainly used for mixing and burning the gases in the desired proportions.
A. True
B. False
.
.Answer: A
Explanation: Process In gas welding, a welding torch is mainly used for mixing oxygen and acetylene in the desired proportions. It is also used for burning the mixture at the end of the tip, and also provides a mean for moving and directing the flame front. Welding torch can be of high pressure type or low pressure type.
Q. Oxy-acetylene Process is most suited for which of the following Process of joining?
A. Metal wires
B. Metal sheets
C. Metal tubes
D. Metal bars
.
.Answer: B
Explanation: Process Oxy-acetylene Process is most suited for the joining of metal sheets or for joining metal plates which are having a thickness of 2mm to 50mm. While joining, the molten metal flows together to form a continuous joint.
Q. For what thickness of a material, in an oxy-acetylene is a welding rod used?
A. 10 mm
B. 15 mm
C. 20 mm
D. 25 mm
.
.Answer: B
Explanation: Process Oxy-acetylene Processes are mainly used for the joining of metal sheets or for joining metal plates which are having a thickness of 2mm to 50mm. When the thickness of the material is more than 15 mm, an additional filler metal is added like a welding rod.
Q. What is the flame temperature of city gas?
A. 1500°C
B. 1600°C
C. 1700°C
D. 1800°C
.
.Answer: C
Explanation: Process City gas is a type of fuel gas that is used for the welding of thin sheets of steel which have a thickness of up to 3 mm. The flame temperature of city gas is approximately about 1700°C.
Q. In a neutral flame, what is the temperature in the inner core?
A. 3200°C
B. 2100°C
C. 1250°C
D. 2700°C
.
.Answer: A
Explanation: Process When equal amount of oxygen and acetylene is made to react in a torch, a neutral flame gets produced. The inner core has a temperature of 3200°C, whereas the tip of the neutral flame has a temperature of 1250°C.
Q. What is the flame temperature of water gas?
A. 2500°C
B. 2800°C
C. 2300°C
D. 3100°C
.
.Answer: C
Explanation: Process Water gas is a type of fuel gas that is used for the welding of thin sheets of steel which have a thickness of up to 8 mm. The flame temperature of water gas is approximately about 2300°C.
Q. Carburising flame has excess of oxygen supply.
A. True
B. False
.
.Answer: B
Explanation: Process None.
Q. What is the flame temperature of methane?
A. 2000°C
B. 1200°C
C. 2700°C
D. 3300°C
.
.Answer: A
Explanation: Process None.
Q. Oxidizing flame has equal volumes of oxygen and acetylene supply.
A. True
B. False
.
.Answer: B
Explanation: Process A neutral flame is the one in which there is an equal amount of supply of oxygen and acetylene. A carburising flame is the one in which the supply of acetylene is much more than that of oxygen and an oxidizing flame is the one where there is ample supply of oxygen compared to acetylene.
Q. What is the flame temperature of acetylene?
A. 1700°C
B. 2200°C
C. 2800°C
D. 3200°C
.
..Answer: D
Explanation: Process Acetylene gas is a type of fuel gas that is used for the welding of thin sheets of steel which have a thickness of up to 50 mm. The flame temperature of acetylene gas is approximately about 3200°C.
Q. What is the flame temperature of hydrogen?
A. 2000°C
B. 1200°C
C. 2700°C
D. 3300°C
.
.Answer: C
Explanation: Process None.
Q. What is the order of temperature of heat produced in an electric arc furnace?
A. 3000°C – 4000°C
B. 4000°C – 5000°C
C. 5000°C – 6000°C
D. 6000°C – 7000°C
.
..Answer: D
Explanation: Process An electric arc furnace generates a lot of heat when the working metal comes in contact with the electrode. The heat that is generated in this joining Process is of the order 6000°C to 7000°C.
Q. The distance from the center of arc to the tip of electrode is called what?
A. Arc distance
B. Arc length
C. Arc crater
D. Arc depth
.
.Answer: B
Explanation: Process The distance from the center of the arc to the tip of the electrode, right till the bottom of the crater is defined to be the arc length. The arc length is considered to be one of the most essential variable in welding Process.
Q. What is the length of the arc generally?
A. 1mm – 2mm
B. 2mm – 3mm
C. 3mm – 4mm
D. 4mm – 5mm
.
.Answer: C
Explanation: Process None.
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Q. In arc welding Process, the high quality alternator functions at what frequency?
A. 250 Hz
B. 300 Hz
C. 350 Hz
D. 400 Hz
.
..Answer: D
Explanation: Process In an arc welding Process, there are alternators used for producing high current and function at lower frequency, and there are alternators which are of high quality and work at high frequency. The functioning frequency of these alternators is 400 Hz.
Q. Which type of electrode is designed for melting quickly?
A. Fast fill
B. Fast freeze
C. Quick fill
D. Fill freeze
.
.Answer: A
Explanation: Process Electrodes which are classified into three types, fast fill, fast freeze and fill freeze. Among these, the fast fill electrodes are considered to be able to operate at extremely high welding speeds, and hence fast fill electrodes are designed for quick melting.
Q. What amount of electricity gets converted into heat energy in an arc welding Process?
A. 0.25 kWh
B. 0.75 kWh
C. 1 kWh
D. 2 kWh
.
.Answer: C
Explanation: Process In an arc welding Process, there is a direct conversion of electrical energy into heat energy. An approximate amount of 1 kilo Watt hour of electrical energy gets converted into heat energy for this Process.
Q. Arc welding machine uses only D.C. supply.
A. True
B. False
.
.Answer: B
Explanation: Process Arc welding machines are able of working on both alternating current supply as well as direct current supply. But mainly arc welding machines work on D.C. supply only, where the positive terminal is connected to the welding machine.
Q. Which type of electrode is designed for melting quickly?
A. Fast fill
B. Fast freeze
C. Quick fill
D. Fill freeze
.
.Answer: B
Explanation: Process Electrodes which are classified into three types, fast fill, fast freeze and fill freeze. In fast freeze electrodes, a filler metal is supplied. This filler element gets solidifies and provides a variety in positions of the weld.
Q. Which material is not used as an iron coating on the electrode used in arc welding?
A. Cellulose
B. Iron powder
C. Calcium fluoride
D. Steel
.
..Answer: D
Explanation: Process Materials that are used as coating on the electrode, that are used in arc welding, are cellulose, iron powder, calcium fluoride and rutile. Iron is used for ease of weld, but not steel, though it mainly contains iron.
Q. The negative pole of the electrode burns away faster than the positive pole.
A. True
B. False
.
.Answer: B
Explanation: Process During the operation of the arc welding Process, the positive pole of the electrode experiences two third of the heat and the negative pole experiences one third the heat, hence the positive pole burns away faster than the negative pole.
Q. What is the capacity of an automatic welding machine?
A. 100 to 200A
B. 300 to 400A
C. 500 to 700A
D. 800 to 3000A
.
..Answer: D
Explanation: Process An automatic welding machine has a high amount of capacity. Its capacity ranges in between 800 to 300A. This type of machine is not portable and is suitably used for heavy welding Processes.
Q. What is the capacity of a light manual welding machine?
A. 100 to 200A
B. 300 to 400A
C. 500 to 700A
D. 800 to 3000A
.
.Answer: A
Explanation: Process A light manual welding machine has one of the lowest capacity among all types of welding machines. Its capacity ranges in between 100 to 200A. This machine is portable and is best suited for light welding Processes.
Q. What is the current required in an Oxygen’s INDARC 400 (S) transformer?
A. 20 amp to 100 amp
B. 40 amp to 250 amp
C. 50 amp to 400 amp
D. 60 amp to 500 amp
.
.Answer: C
Explanation: Process In an Oxygen’s INDARC 400 (S) transformer, there is a hand wheel provided which is used for varying the output, for altering the air gap in the core and results in regulating the current in between 50 amperes to 400 amperes.
Q. What is the efficiency of an A.C. welding transformer?
A. 0.6
B. 0.7
C. 0.8
D. 0.9
.
.Answer: C
Explanation: Process A.C welding is currently gaining considerable ground. The efficiency of an alternating current welding transformer varies from 0.8 to 0.85 and the efficiency of A.C. outfits is in the range of 0.3 to 0.Q.
Q. What is the amount of electric energy required per kg in dc welding operation?
A. 1-4 kWh
B. 3-7 kWh
C. 4-9 kWh
D. 6-10 kWh
.
..Answer: D
Explanation: Process The amount of electrical energy consumed required per kg for a D.C. welding operation, is 6 kWh to 10 kWh. Direct current provides the advantage of distribution of the heat needed inside the arc.
Q. Which material is not used for making non-consumable electrodes?
A. Carbon
B. Graphite
C. Sodium
D. Tungsten
.
.Answer: C
Explanation: Process Non-consumable electrodes, are those electrodes which do not get consumed as the welding operation proceeds. These electrodes are primarily made up of materials like carbon, graphite and tungsten.
Q. Which of the following characteristic does not define a coated electrode?
A. Maintenance of arc
B. Protection from oxygen
C. Protection from nitrogen
D. Preventing other elements into molten metal
.
..Answer: D
Explanation: Process A coated electrode is a further classification of a consumable electrode. The purpose of the electrode is to maintain the arc, to shield the molten metal from oxygen and nitrogen present in the air and to provide other alloying elements into the molten metal.
Q. What is the amount of carbon contained by a soft steel wire?
A. 0.1% to 0.18%
B. 0.15% to 0.22%
C. 0.18% to 0.26%
D. 0.2% to 0.27%
.
.Answer: A
Explanation: Process A soft steel wire contains about 0.1% to 0.18% of carbon. Soft steel wire also has other contents in it like phosphorous and sulphur in it. The amount of phosphorous is soft steel is around 0.0025%.
Q. What is the percentage of carbon present in low alloy steel?
A. 0.15%
B. 0.2%
C. 0.25%
D. 0.3%
.
.Answer: C
Explanation: Process The amount of carbon that is present in a soft steel wire is around 0.1% to 0.18% and the amount of carbon in terms of percentage composition in low alloy steels is 0.25%.
Q. The presence of arc blower makes good quality welds.
A. True
B. False
.
.Answer: B
Explanation: Process A flow of large amount of current causes the generation of arc blower. The space around the arc and the metal always experience magnetic fields, causing the currents to get squared. This results in an unstable behavior by the arc blower, which is therefore not desirable for good welds.
Q. Why is carbon used in carbon arc welding?
A. Generation of more heat at electrode tip
B. Generation of less heat at electrode tip
C. Provides coating
D. Fixed polarity is maintained
.
.Answer: B
Explanation: Process Carbon is used in carbon arc welding, at the negative terminal of the cathode. The reason for employing carbon at the negative terminal is that, a lesser amount of heat is generated at the electron tip than at the workpiece.
Q. What is the temperature at the negative terminal in carbon arc welding?
A. 3000°C
B. 3100°C
C. 3200°C
D. 3300°C
.
.Answer: C
Explanation: Process None.
Q. The Process of carbon arc welding is not used for which of the following material?
A. Copper
B. Bronze
C. Aluminium
D. Iron
.
..Answer: D
Explanation: Process The Process of carbon arc melting is widely used for copper and copper alloys, hence bronze and brass are treated by this method. Aluminium can also be treated likewise, but not iron metal.
Q. Which gas is used as a protection in carbon arc welding?
A. Carbon dioxide
B. Carbon monoxide
C. Carbon tetra fluoride
D. Methane
.
.Answer: B
Explanation: Process In carbon arc welding, there has to be a protection to be provided to the molten weld. This protection is provided in the form of an envelope by using a long arc giving carbon monoxide gas.
Q. What is the temperature at the positive terminal in carbon arc welding?
A. 3800°C
B. 3900°C
C. 4000°C
D. 4100°C
.
.Answer: B
Explanation: Process Carbon is used in carbon arc welding, at the negative terminal of the cathode and the metal which is being worked upon functions as the positive terminal. The temperature of the electrode at the positive terminal is 3900°C.
Q. What is the temperature of the negative electrode in metal arc welding?
A. 2200°C
B. 2300°C
C. 2400°C
D. 2500°C
.
.Answer: C
Explanation: Process In metal arc welding, the temperature of negative electrode is higher than the temperature of positive electrode. The temperature produced in a negative electrode of a metal arc weld is about 2400°C.
Q. What is the temperature of the positive electrode in metal arc welding?
A. 2300°C
B. 2400°C
C. 2500°C
D. 2600°C
.
..Answer: D
Explanation: Process None.
Q. Which bead character is seen due to too high welding current?
A. Pilling of metal
B. Pilling of weld metal
C. Excess splatter
D. Small bead formation
.
.Answer: C
Explanation: Process On provision of too low current, there is pilling of metal seen. When the voltage provided is very high, beads formed are too high. When the speed of weld is less, pilling of weld metal takes place and when welding currents are too high, excessive splatter formation occurs.
Q. A smooth and regular bead cannot be formed in metal arc welding.
A. True
B. False
.
.Answer: B
Explanation: Process Before the welding starts, the machine has to be adjusted very correctly. The current to be supplied and the voltage to be applied should not to be too low or high, and the welding speed should be normal. By doing this, regular and smooth beads will be formed.
Q. Carbon is intended to be mixed in small amounts in the weld, in carbon arc welding.
A. True
B. False
.
.Answer: B
Explanation: Process In carbon arc welding, the carbon is present at the negative electrode, where the electrode temperature is at 3200°C. This temperature is lesser than that at the positive electrode. Carbon electrode is kept at a lower temperature on the negative electrode, to avoid the mixing of carbon in the weld. If the carbon gets mixed with the weld, the weld might end up becoming brittle.
Q. Which kind of resistance is experienced in upset butt welding?
A. Electric resistance
B. Magnetic resistance
C. Thermal resistance
D. Air resistance
.
.Answer: A
Explanation: Process In the making of an upset butt welding, there are jaws made of copper, into which the part to be welded is put, and hence a solid contact is made. At this point of contact, while the current flows, it gets transformed into heat because of electric resistance.
Q. Which of the following can be easily be welded from flash butt welding Process?
A. Tin
B. Lead
C. Cast irons
D. Carbon steel
.
..Answer: D
Explanation: Process In flash butt welding Process, the welding of materials like steels and other iron alloys are easy to weld, except for cast iron. The welding of materials like tin, lead, zinc and antimony cannot be welded using flash butt method.
Q. Electrodes used in spot welding are made up of which material?
A. Only Copper
B. Copper and tungsten
C. Copper and chromium
D. Copper and aluminium
.
..Answer: D
Explanation: Process The electrodes that are employed in the spot welding are required to possess a high amount of electrical and thermal conductivity. Hence, they are primarily made up of copper or copper and tungsten or copper and chromium.
Q. How are the metals to be welded connected to each other in spot welding?
A. Electric contact
B. Magnetic field
C. Mechanical pressure
D. Direct contact
.
.Answer: C
Explanation: Process In spot welding Process, the metal or the alloy parts which are to be welded, are heated in their in their zones. To bring these parts in contact with one another, mechanical pressure is applied, causing them to connect.
Q. Which of the following method is not used in applying pressure in spot welding Process?
A. Hand lever
B. Foot lever
C. Air pressure
D. Hydraulic cylinder
.
.Answer: A
Explanation: Process None.
Q. Up to what thickness, can steel be welded using spot welding Process?
A. 10 mm
B. 11 mm
C. 12 mm
D. 13 mm
.
.Answer: C
Explanation: Process In spot welding Process, to bring the heated parts in contact with one another, mechanical pressure is applied. This pressure can be of three types, by using foot lever, by providing air pressure or by using a hydraulic cylinder. The use of these methods allows steel or other metal parts to be welded up to a thickness of 12 mm.
Q. What is the maximum power supply needed for the working of spot welding Process?
A. 135 kVA
B. 140 kVA
C. 145 kVA
D. 150 kVA
.
..Answer: D
Explanation: Process Spot welding can be used for all types of ductile metals. It can also be employed for structures of sheet metals, and can be applied for making of boxes and cans. For its applications, the maximum power that can be needed for this Process is 150 kVA.
Q. What is the minimum power supply needed for the working of spot welding Process?
A. 10 kVA
B. 14 kVA
C. 6 kVA
D. 22 kVA
.
.Answer: A
Explanation: Process None.
Q. Upset butt welding is majorly used in the making of automobile parts.
A. True
B. False
.
.Answer: B
Explanation: Process Upset butt welding is mainly used for the manufacture of welding bars, rods, wires or tubing. For the manufacture of automobile parts, such as axles, wheels or frames, flash butt welding is extensively used.
Q. In flash butt welding, the forced out metal is called flash.
A. True
B. False
.
.Answer: A
Explanation: Process In flash butt welding Process, there is a light contact between the edges. A high voltage is supplied when the flashing action takes place. In this Process, the metal that is forced out, is called as flash.
Q. After the achievement of welding temperature, electrical connections are established to complete the weld.
A. True
B. False
.
.Answer: B
Explanation: Process The superheated melt is heated from the crucible gets poured around the metal parts. As the welding temperature is achieved, there is an application of mechanical pressure to the weld.
Q. What is the magnitude of temperature produced in a thermit reaction?
A. 2500°C
B. 3000°C
C. 3500°C
D. 4000°C
.
.Answer: B
Explanation: Process Thermit welding is called as fusion welding. A superheated melt operates in this type of melt. The heat that is produced has the temperature approximately twice than that of the melting point of steel, which is about 3000°C.
Q. Thermit welding is used for making rail tracks.
A. True
B. False
.
.Answer: A
Explanation: Process A superheated melt operates in this type of melt. The production of pipes, rail tracks, shafts or big gears can be done using thermit pressure welding. Thermit welding is called as fusion welding.
Q. In an iron thermit, how many moles of aluminium reacts with three moles of iron oxide to give nine moles of iron?
A. 6
B. 7
C. 8
D. 9
.
.Answer: C
Explanation: Process The thermit Process, which is used for welding depends on the chemical reaction between oxide of iron and aluminium metal. According to this reaction, when 8 moles of aluminium reacts with 3 moles of iron oxide, then, 4 moles of aluminium oxide and 9 moles of iron is formed.
Q. At what temperature, does fusion welding takes place?
A. 850°C
B. 900°C
C. 950°C
D. 1000°C
.
.Answer: B
Explanation: Process The Process of fusion welding can be used for joining metal to a metal or a metal can be joined to a ceramic. For the joining of this Process, a temperature of 900°C is provided for the approach.
Q. Which of the following is not a type of diffusion welding?
A. Gas-pressure welding
B. Vacuum fusion welding
C. Eutectic fusion bonding
D. Eutectoid fusion welding
.
..Answer: D
Explanation: Process Diffusion welding is has three basic techniques which are incorporated by it. These three basic techniques are, gas – pressure welding, vacuum fusion welding and eutectic fusion welding.
Q. What is the minimum frequency used in ultrasonic welding?
A. 10,000 Hz
B. 20,000 Hz
C. 30,000 Hz
D. 40,000 Hz
.
.Answer: B
Explanation: Process The Process of ultrasonic welding is mainly used for the joining of similar metals or dissimilar metals using vibration energy, by way of high frequency. The minimum frequency needed for this purpose is 20,000 Hz.
Q. What is the maximum frequency used in ultrasonic welding?
A. 30,000 Hz
B. 40,000 Hz
C. 50,000 Hz
D. 60,000 Hz
.
..Answer: D
Explanation: Process None.
Q. In what conditions are the parts kept before welding in ultrasonic welding method?
A. Low static pressure
B. High static pressure
C. Low moving pressure
D. High moving pressure
.
.Answer: A
Explanation: Process In ultrasonic welding method, the parts which are to be joined, are kept clamping to one another in between of supporting member and the welding tip. This clamping is done at a low static pressure.
Q. What is the maximum thickness that can be welded in ultrasonic welding?
A. Q.8 mm
B. Q.1 mm
C. Q.3 mm
D. Q.5 mm
.
..Answer: D
Explanation: Process Weldings such as spot welding or continuous seam welding can be done through ultrasonic welding. The maximum thickness that can be achieved varies depending on the metal. The maximum thickness can be that can be welded is Q.5mm.
Q. Electric currents are passed is ultrasonic welding.
A. True
B. False
.
.Answer: B
Explanation: Process In ultrasonic welding method, the parts which are to be joined, are kept clamping to one another in between of supporting member and the welding tip. In doing this, no current is required to be passed through the metal, and usually, no heat is needed for this too.
Q. What is the minimum thickness that can be welded in ultrasonic welding?
A. 0.58 mm
B. 0.21 mm
C. 0.38 mm
D. 0.92 mm
.
.Answer: C
Explanation: Process None.
Q. Which of the following is not a factor for explosive welding?
A. High relative velocity
B. Less amount of plastics
C. Proper orientation
D. High pressure
.
.Answer: B
Explanation: Process While considering for explosive welding, the factors that one needs to understand is that, there has to be high relative velocity. There should be proper orientation and it needs to be kept under high amount of pressure.
Q. ‘α’ is the angle between target plate and flyer plate.
A. True
B. False
.
.Answer: A
Explanation: Process The workpiece which has its position fixed is called as the target plate and the other plate is called as flyer plate. The distance between the two plates is denoted by ‘d’ and the angle between them is denoted by ‘α’.
Q. Which gas is used for the removal of oxygen layer formed on molten iron?
A. Hydrogen
B. Oxygen
C. Carbon dioxide
D. Chlorine
.
.Answer: B
Explanation: Process In oxygen cutting method, under considerable amount of pressure, when a jet of oxygen gas is made to blow on the particles of molten iron oxide, the oxygen layer present on the molten iron gets removed.
Q. Up to what amount of carbon content in steels, can they be treated by oxygen cutting?
A. 0.3%
B. 0.2%
C. 0.7%
D. 0.4%
.
.Answer: C
Explanation: Process For a steel to be treated by oxygen cutting Process, the carbon content that should be available in terms of percentage composition is around 0.7%, that is, the steel that can be treated by this Process is a high alloy steel.
Q. Up to what temperatures are high alloy steels heated before treating them by oxygen cutting?
A. 675°C
B. 725°C
C. 775°C
D. 825°C
.
.Answer: A
Explanation: Process In oxygen cutting Process, not all steels can be treated by this method. Only high alloy steels can be treated by this method. These steels need to be preheated before oxygen cutting. The temperature range up to which these steels are preheated is about 650°C to 700°C.
Q. What are the number of opening available in the cutting torch used in oxygen cutting Process?
A. 4
B. 5
C. 6
D. 7
.
..Answer: D
Explanation: Process Just like any other gas welding equipment, the welding torch gets substituted by a cutting torch in oxygen cutting Process. The total number of openings available in the torch are six, with a large opening at the center, making the count to seven.
Q. What is the maximum oxygen pressure that can be applied to steel?
A. 13 atm
B. 14 atm
C. 15 atm
D. 16 atm
.
.Answer: B
Explanation: Process None.
Q. What is the minimum oxygen pressure that can be applied to steel?
A. 3 atm
B. 4 atm
C. 5 atm
D. 6 atm
.
.Answer: A
Explanation: Process In oxygen cutting Process, not all steels can be treated by this method. Only high alloy steels can be treated by this method. The pressure supply of oxygen should not be low, as it may lead to the formation of slag on the bottom of the cut. The minimum oxygen pressure that can be applied to steels is 3 atmospheres or 300 kN/mQ.
Q. What is the initial oxygen pressure provided through the lance?
A. 1 atm to 2 atm
B. 2 atm to 3 atm
C. 3 atm to 4 atm
D. 4 atm to 5 atm
.
.Answer: A
Explanation: Process In oxygen lance cutting, jet of oxygen is passed through steel pipes, and by doing this, holes are produced. For doing this, the jet of oxygen is passed through the lancer under the pressure of 1 atm to 2 atm.
Q. What should the outer diameter of a thick-welled lance be, for having good results?
A. 13 mm to 15 mm
B. 15 mm to 17 mm
C. 17 mm to 19 mm
D. 19 mm to 21 mm
.
.Answer: C
Explanation: Process In oxygen lance cutting, when the lance is made up of a thick wall, with its outer diameter of 17 mm to 19 mm, and possessing an inner diameter of 8 mm to 6 mm, respectively, then good results can be obtained.
Q. Cast irons are best treated using oxygen cutting Process.
A. True
B. False
.
.Answer: B
Explanation: Process Cast irons cannot be treated using oxygen cutting Process. The reason being that the melting point of cast irons is a lot lower than its ignition temperature. The same cannot be said for high alloy steels.
Q. Oxygen cutting Process can be applied to metals having a melting point higher than their oxidization temperature.
A. True
B. False
.
.Answer: B
Explanation: Process It can be counted among one of the drawbacks of oxygen cutting Process, that the metal which is to be treated must have its oxidizing temperature higher than its melting temperature, otherwise the metal would get melted before getting oxidized.
Q. Which of the following methods cannot be used for welding carbon steel?
A. Arc welding
B. Gas welding
C. Ultrasonic welding
D. Forge welding
.
.Answer: C
Explanation: Process For the welding of carbon steel material, one may use the arc welding method. To gas weld carbon steel is also a feasible option and carbon steels can be treated using forge welding also, but it cannot be welded using ultrasonic welding.
Q. High alloys steels are preheated up to what temperature?
A. 350°C
B. 400°C
C. 450°C
D. 500°C
.
.Answer: B
Explanation: Process High alloy steels are those steels which contain high amount of carbon in them. These alloys need to be preheated before welding in order to avoid cracking. The temperature up to which these alloys are preheated is 400°C.
Q. Up to what percent of carbon content in steel, it is not required to preheat it?
A. 0.25% – 0.3%
B. 0.3% – 0.35%
C. 0.35% – 0.4%
D. 0.4% – 0.45%
.
.Answer: A
Explanation: Process Low carbon steels are the ones containing low amount of carbon in them, which does not require preheating. The amount of carbon content needed in low carbon steels, is 0.25% to 0.3%, if preheating is to be avoided.
Q. Which of the following material is not used in alloy steels?
A. Molybdenum
B. Nickel
C. Chromium
D. Sodium
.
..Answer: D
Explanation: Process In alloy steels, there is a big composition used up by iron. Along with iron, there vitally has to be carbon in alloy steels. Along with carbon, there is a presence of other elements such as, molybdenum, nickel and chromium in small amounts.
Q. Which among the following methods is best suited for stainless steels?
A. Electric butt welding
B. Seam welding
C. Flux coated arc welding
D. Oxy-hydrogen welding
.
.Answer: A
Explanation: Process There are a few methods of treating stainless steels for welding, such as, any of the metal arc welding methods or the oxy-acetylene welding method, but the one best suited for this alloy is electric butt welding.
Q. Stainless steels are annealed at what temperature?
A. 650°C – 700°C
B. 700°C – 750°C
C. 750°C – 800°C
D. 800°C – 850°C
.
.Answer: C
Explanation: Process Stainless steels are hardened by constant heating and cooling and the best method suited for this alloy is electric butt welding. As soon as the stainless steel alloy is electric butt welded, it needs to be annealed at a temperature in between 750°C to 800°C.
Q. Which of the following is not a material used for making an electrode in metal arc welding, for treating stainless steels?
A. Niobium
B. Columbium
C. Titanium
D. Potassium
.
..Answer: D
Explanation: Process Stainless steels are best welded using the electric butt welding method and then followed by annealing at around 750°C to 800°C. Stainless steels can also be welded using the metal arc welding methods. For this the electrode which is needed is made up of niobium, titanium and columbium. These materials avoid the occurrence of the defect called weld decay.
Q. What is the temperature needed for preheating in cast irons?
A. 550°C
B. 600°C
C. 650°C
D. 700°C
.
.Answer: B
Explanation: Process Cast irons, upon the removal of welding heat, get solidified very quickly. This solidification takes place due to the surrounding cold mass and the air around. Because of such quick cooling, the carbon gets retained and hard metal stays in the weld. To overcome this, cast irons have to be preheated to 600°C.
Q. Low carbon steels need not be preheated before welding.
A. True
B. False
.
.Answer: A
Explanation: Process Carbon steels which contain carbon in a very low amount are not compulsorily required to be preheated before undergoing welding if the large runs are made. This is because, in low carbon steels, unlike high carbon steels, there is no cracking seen on welding.
Q. Carbon steels can be fusion welded.
A. True
B. False
.
.Answer: B
Explanation: Process Carbon steels are best treated using forge welding, resistance welding, arc welding or by gas welding. Carbon steels essentially cannot be fusion welded, because, of the occurrence of cracks which may cause due to carbon pick up.
