Welding Assignment Solutions PDF

Assignment 1 solution 1. The welding process most commonly used in the construction of automobiles is a) Gas tungsten arc welding b) Resistance welding c) Submerged arc welding d) Shielded metal arc welding 2. High thermal expansion coefficient metals pose challenges during...

Assignment 1 solution 1. The welding process most commonly used in the construction of automobiles is a) Gas tungsten arc welding b) Resistance welding c) Submerged arc welding d) Shielded metal arc welding 2. High thermal expansion coefficient metals pose challenges during welding in the form of a) Partial melting of metals to be welded b) Distortion in joint due to expansion and contraction during the welding process c) Corrosion in welded joint d) Development of uniform properties across the joint 3. The fundamental mechanism(s) used in joining processes is/are a) Deformation b) Diffusion c) Fusion d) All of these 4. An example of a solid-state process joining is a) Brazing b) Arc welding c) Friction stir welding d) Laser welding 5. Joining of thin sheets is considered autogenous welding by a) Electron beam welding b) Submerged arc welding c) Shielded metal arc welding d) Gas metal arc welding 6. A type of welding based on radiation energy is a) Ultrasonic welding b) Arc welding c) Laser beam welding d) Gas welding 7. The primary role of chemical reactions in thermite welding is a) Generating heat through an exothermic reaction b) Generating heat through endothermic reaction c) Generating heat through both exothermic and endothermic reactions d) Generating gas for protecting weld pool 8. With increase of energy density of the welding process, the effect of weld size and heat- affected zone size is a) Both weld size and HAZ size increased b) Weld size decreased while HAZ size increased c) Both weld size and HAZ size decreased d) Weld size increases while HAZ size decreased 9. The primary reason for the formation of porosity in fusion weld joints is a) The difference in solubility of gases between the liquid and solid states of the metal b) The incomplete melting of flux from the weld pool c) The slow cooling rate of the molten metal d) Reaction of oxygen gas with molten metal 10. In submerged arc welding, welding pool protection is done by a) Inert gas shielding b) Inactive gas shielding c) Vacuum d) Forming cover of molten flux or slag  Assignment 2 solution 1. The preferred grain structure of weld metal in fusion weld joint for good mechanical properties is a) Planar b) Cellular c) Equiaxed d) Dendritic 2. The temperature of an oxidising flame in gas welding is _____ that of a carburising flame. a) Lower than b) Higher than c) Equal to d) No relationship 3. A major disadvantage of gas welding compared to arc welding is a) Greater risk of electrical shock b) Inability to weld dissimilar metals c) Lower power density, resulting in a larger heat-affected zone d) Higher cost of materials and equipment 4. Select the most difficult welding position a) Flat welding b) Overhead welding c) Vertical welding d) Horizontal welding 5. The 'coating factor' of SMAW electrode indicates a) The amount of flux in the coating b) The percentage of alloying elements in the coating c) The ratio of the electrode's overall diameter to the core wire diameter d) The efficiency of the coating in protecting the weld pool 6. The primary limitation on the maximum welding current used in the shielded metal arc welding process is a) Excessive heat generation leads to thermal damage to electrode coating b) Limited arc stability at high currents c) Risk of undercutting the weld at high currents d) Difficulty in controlling the arc length at high currents 7. DCEN (electrode negative) polarity in TIG welding a) Increases heat generation at the electrode b) Decreases weld penetration depth c) Enhances cleaning action d) Improves arc stability 8. For welding aluminium, the primary purpose of using AC polarity in the GTAW process is a) To increase the arc stability b) To increase the melting rate of the electrode c) To achieve both lower heat generation on the electrode side and cleaning action d) To increase the melting rate of the workpiece 9. The main advantage of using coated Tungsten electrode compared to pure Tungsten electrode is a) Decreased the melting point b) Increased current carrying capacity c) The increased corrosion resistance d) Increased the strength of the weld 10. Select the correct statement about the TIG welding process a) The TIG process uses lowest net heat input compared to other common arc welding processes b) The TIG process cannot be used for welding ferrous metals c) The TIG process has the highest penetration depth d) The TIG process can weld thicker materials in a single pass  Assignment 3 solution 1. Select the correct variant of the GTAW process aims to improve penetration depth while maintaining same net heat input. a) Hot Wire GTAW b) GTAW with filler c) Pulse GTAW d) Conventional GTAW 2. The primary function of the AC power supply to filler in the Hot Wire GTAW process is a) To regulate the welding arc b) To preheat the filler wire c) To reduce the arc blow effect d) To enhance the penetration depth 3. The use of activated fluxes in Activated Flux GTAW reverses the Marangoni convection, which in turn causes a) A change in the direction of molten metal flow b) Increased heat input c) A reduction in the arc constriction effect d) A decrease in the surface tension of the molten metal 4. Select the correct statement in respect of arc welding like GMAW with DC reverse polarity. a) The workpiece is connected to the negative terminal, and the electrode is connected to the positive terminal of the DC power source b) Low deposition rate c) High penetration depth d) Less heating of the electrode 5. The term 'cold' in Cold Metal Transfer welding refers to a) The temperature of the workpiece during welding b) The use of a cooling system during the process c) The relatively low heat input compared to other GMAW variants d) The absence of any heat generation during the process 6. The power source typically used for submerged arc welding with electrodes less than 2.4 mm in diameter is a) Constant current b) Constant voltage c) Alternating current d) Direct current pulse 7. The factor(s) contributing to the high arc efficiency of submerged arc welding is/are a) A thick molten layer of flux over the weld pool b) Low welding speed c) Use of a constant voltage power source  d) All of these 8. The primary reason for using copper shoes in the Electro-slag welding process is a) To provide electrical conductivity b) To improve the heat generation in the weld pool c) To prevent the flow of molten metal outside the weld zone d) To enhance the appearance of the weld 9. Crystal used in laser welding to emit radiation is a) Iron b) Copper c) Ruby d) Platinum 10. In laser welding, the rapid cooling of the weld pool increases the chances a) Amorphous structure b) Porosity c) Cracking in hardenable steel d) All of these  Assignment 4 solution 1. A typical application of soldering is a) Joining carbide tips to cutting tools b) Creating electrical connections in electronic devices c) Joining heat exchanger components d) Manufacturing jewellery 2. Soldering is a/an a) Homogeneous joining methods b) Heterogeneous joining methods c) Autogenous Joining methods d) Mechanical joining methods 3. The filler rod material used for the soldering process is a) Brass b) Bronze c) Lead and tin alloy d) Cu, Zn, Ag alloy 4. Carbide tip in cutting tools is joined by a) Brazing b) Soldering c) Welding d) Casting 5. The primary function of pressure in resistance welding is a) To increase the size of the nugget b) To ensure firm metallic contact between the workpiece c) To prevent the expulsion of metal d) To prevent the indentation on the workpiece 6. The 'nugget' in resistance welding is a) The area of the workpiece where the electrodes are applied b) Solidified joint in welded pieces of metal after cooling and solidification of molten pool c) The electrode material that melts during the welding process d) The area of the workpiece where the minimum heat is generated 7. The shape of the electrode used in resistance seam welding is a) Flat b) Truncated cone c) Dome d) Cylindrical 8. A preferred combination of sheet material properties for ease of spot welding is a) High electrical resistivity, low thermal conductivity b) Low electrical resistivity, high thermal conductivity c) High electrical resistivity, high thermal conductivity d) Low electrical resistivity, low thermal conductivity 9. The typical application(s) of flash butt welding is/are a) Joining rails b) Joining large-diameter pipes c) Joining chains and girders d) All of these 10. The primary role of pressure in the flash butt welding process a) To remove impurities b) To forge the workpieces together c) To ensure alignment between the workpieces d) To generate heat  Assignment 5 solution 1. The two main types of adhesive bonding that have been developed are a) Structural and Non-structural b) Thermal and Electrical c) Mechanical and Chemical d) Static and Dynamic 2. Joint configurations specifically designed to increase the load-carrying capacity of butt adhesive joint is a) Peeling b) Tongue and Groove c) Cleavage single d) Double lap 3. The 'halo' in weld bonding refers to a) The area where the adhesive is thermally damaged during spot welding b) The area where the metallic connection formed by the spot weld nugget c) The region where the adhesive is applied but not cured d) The area where the pressure during spot welding displaces the adhesive 4. The relationship between the thickness of the adhesive layer and the strength of the joint a) Increases the strength with an increase in thickness b) Decreases the strength with an increase in thickness c) First, the strength decreases, then increases with further increase in thickness. d) No effect on the strength of the joint 5. The solid-state joining process that does not involve the application of external heat is a) Seam welding b) Explosive welding c) Friction stir welding d) High-frequency resistance welding 6. Consider the following characteristics with respect to solid-state joining processes I. No fusion of the metals II. No filler material is typically used III. Solidification cracking tendency in welded joints IV. Dissimilar metals can be joined Select the correct answer using the code given below: a) I, II, III and IV b) I, II and III only c) I, II and IV only d) II, III and IV only 7. The primary mechanism of joining in ultrasonic welding is a) Fusion of the materials  b) Localized elastic and plastic deformation at the interface c) Localized diffusion only at the interface d) Localized elastic deformation only at the interface 8. The maximum temperature rises typically observed during ultrasonic welding is a) 50% to 75% of the melting point of the metal in kelvin b) 35% to 50% of the melting point of the metal in kelvin c) 10% to 20% of the melting point of the metal in kelvin d) 75 to 100% of the melting point of the metal in kelvin 9. The diffusion mechanism that requires the least amount of activation energy is a) Exchange diffusion b) Interstitial diffusion c) Ring diffusion d) Vacancy diffusion 10. Pressure applied during the initial stage of diffusion bonding helps a) To coarsen the grains b) To collapse asperities and increase metal-to-metal contact c) To create a vacuum environment d) To prevent the formation of grain boundaries  Assignment 6 solution 1. The purpose of the buffer layer in explosive welding is a) To increase the impact velocity b) To prevent erosion of the prime component c) To create a more uniform weld d) To distribute the explosive evenly 2. A factor that predominantly affects the strength of an explosive weld joint is a) The waviness of the interface b) The thickness of the buffer layer c) The flatness of the interface d) The thickness of the base plate 3. The limitation of magnetic pulse welding is a) Wide heat-affected zone b) Electrically conductive workpieces only c) Limited to lap joint configuration d) Produces a significant amount of fumes and radiation 4. The typical characteristic of a sound magnetic pulse welded joint interface is a) A smooth, flat surface b) A wavy surface c) A porous and irregular interface d) A perfectly smooth and polished interface 5. The weld thermal cycle indicates a) The heating and cooling rate b) The peak temperature c) The soaking time above a specific temperature d) All of these 6. For same heat input, increasing the thickness of the base metal affects the weld thermal cycle by a) Increasing the peak temperature and reducing the soaking time b) Decreasing the peak temperature and increasing the soaking time c) Increasing the peak temperature and increasing the soaking time d) Decreasing the peak temperature and reducing the soaking time 7. Precipitation-hardened metal systems in HAZ are affected during fusion welding by a) Melting b) Coarsening c) Refinement d) Transformation to hard precipitate 8. The reason for the increasing in hardness of transformation-hardened metals like steel in the HAZ is  a) Refinement of precipitates b) Recrystallization and grain growth c) Dissolution of precipitates d) Formation of hard phase 9. The primary requirement for precipitation hardening in metal systems a) The solubility of alloying elements must decrease with an increase in temperature b) The solubility of alloying elements must increase with an increase in temperature c) The solubility of alloying elements must remain stable with an increase in temperature d) The alloying elements must be chemically inert 10. The size of the heat-affected zone in welding is directly related to a) Welding voltage b) Welding current c) Welding speed d) All of these  Assignment 7 1. Solidification of the weld metals in the fusion welding process takes place by a. Loss of heat from electrode to the faying surface b. Loss of heat from the liquid weld metal to the solid state c. Loss of heat from the base metal to the weld zone d. Heat addition from the thermal source to the weld zone 2. In case of similar metal fusion welding of weld metal, solidification occurs by a. Nucleation and growth only b. Growth only c. Epitaxial growth d. Columnar grain growth 3. Tear drop shape weld pool is observed when a. Welding is performed at very slow speed b. Welding is performed at overhead position c. Welding is performed at very high speed d. Welding is performed vertically 4. In general, an increase in carbon percentage in carbon steel results in a. Increase in ductility and reduction in strength b. Increase in ductility and strength both c. Decrease in ductility, increase in strength and toughness d. Increase in strength, reduction in ductility and toughness 5. Choose the correct sequence of phases in the decreasing trend of their hardness values a. Martensite-ferrite-fine grain pearlite b. Martensite-ferrite-pearlite c. Marteniste-fine grain pearlite-ferrite d. Ferrite-fine grain pearlite-martensite 6. Locked in tensile strain during solidification of weld joint from melting temperature to the room temperature results in a. Compressive residual stress b. Thermal stress c. Tensile residual stress d. Fluctuating stress 7. Factor that increases the solidification cracking tendency a. Higher solidification temperature range b. Finer grain structure c. Curved grain structure d. Higher surface tension of the grain boundary liquid 8. Tensile residual stress will be developed at the surface of fillet weld joint if the weld bead geometry is of a. Convex shape b. Concave shape c. Flat bead d. Residual stress does not depends upon the weld bead geometry 9. Cold cracking of weld joint can not be minimised using a. Preheat of the weld metal b. Filler metal of high yield strength  c. Post weld heat treatment d. Reducing tensile residual stress 10. The chances of solidification cracking will be minimum if the weld joint of composition is a. Eutectic alloy b. Hypoeutectic alloy c. Hypereutectic alloy d. All of the above  Assignment 8 1. Severity of heat affected zone is maximum during a. Fusion welding b. Solid-state welding c. Brazing d. All of the above 2. Micro level plastic deformation is realised in the welding process of a. Fusion welding b. Friction welding c. Friction stir welding d. Ultrasonic welding 3. With the addition of alloying elements/impurities in the metal system, melting point a. Increases b. Reduces c. First increases then decreases d. Does not vary 4. For the edge preparation of hardenable metal usually flame cutting is not preferred because of a. Formation of soft and ductile structure b. Formation of hard and ductile structure c. Formation of hard and brittle structure d. Formation of bainitic structure 5. Formation of the hard phases intermetallic compound within the fusion weld zone will leads to the a. Softening of weld zone b. Hardening of the weld zone c. Hardening of the base metal d. Softening of the heat affected zone 6. Softening of the weld zone during fusion welding will make the a. Base metal weaker b. Weld zone stronger c. Weld zone weaker d. Heat affected zone stronger 7. Work hardening of metal results into the a. Increase in yield strength, increase in tensile strength and decrease in ductility b. Decrease in yield strength, decrease in tensile strength and increase in ductility c. Increase in yield strength, decrease in tensile strength and increase in ductility d. Decrease in yield strength, increase in tensile strength and decrease in ductility 8. Arrange the phases in increasing order of crack tendency of steel weld joint a. Martensite – bainite – ferrite b. Bainite – martensite- ferrite c. Martensite- ferrite- bainite d. Ferrite – bainite – martensite 9. Work hardenable metal subjected to the plastic deformation leads to the a. Increase in dislocations b. Reduction in toughness  c. Increase the ductile to brittle transition temperature d. All of the above 10. In the work hardened materials the strengthening property is mainly achieved by a. Precipitates formation b. Dislocation presence c. Finer grain size d. Coarser grain size  Assignment 9 1. Welding process of high heat input for welding of metals leads to a. Larger grain growth b. Lesser grain growth c. Short high temperature retention time d. All of the above 2. The minimum hardness of the precipitate-hardened metal joined by tungsten inert gas welding occurs in a. Thermo-mechanically affected zone b. Weld zone c. Heat affected zone d. Base metal 3. Heating of precipitate-hardened metal above the solvous line temperature will leads to the a. Single phase solid solution b. Transformation hardening c. Guinier preston zone formation d. Precipitate formation 4. Strength in precipitation hardenable stainless steel is achieved by the formation of a. Sigma phase b. Martensite c. Chromium carbide d. Ferrite 5. Beyond the critical radius of the precipitates, the strength in precipitate-strengthening metal is achieved by the process of a. Cutting down of precipitates b. Bowing down of the precipitates c. Bowing down of the dislocation around the precipitates d. All of the above 6. Precipitate hardened metal, if joined by plastic deformation based joining method like FSW then the minimum hardness will be in the a. Base metal b. Weld zone c. Heat affected zone d. All of the above 7. Grain structure in the joining of grain refinement metal by fusion welding process will be a. Finer grain size at the grain boundary and coarser at the weld centre b. Coarser grain size at the grain boundary and finer at the weld centre c. Finer grain size at the grain boundary and at the weld centre both d. Coarser grain size at the grain boundary and at the weld centre both 8. A wetting issue caused in the fusion welding process of a. Precipitate strengthening metal b. Grain refinement strengthening metal c. Dispersion strengthening metal d. Work hardening metal 9. Austenitic steel components offer good cavitation resistance due to a. Low hardness b. High hardness c. Conversion of Austenite into Martensitic steel  d. High strength 10. Joining of transformation hardening metals like alloy steel resulting strength in weld metal mainly due to a. Change in grain size b. Strain hardening c. Transformation of soft phase into hard phase d. All of the above  Assignment 10 1. Advantage of plastic deformation based welding over fusion welding are a. Narrow width of heat affected zone b. Higher strength c. Lower cost d. Favourable grain structure 2. For the same plate thickness, the width of the heat-affected zone is minimum in a. Electron beam welding b. GTAW c. GMAW d. Submerged arc welding 3. During the dissimilar welding of ferritic steel of 0.2% carbon and austenitic stainless steel of 0.05% carbon, carbon migration leads to a. Depletion of carbon in ASS and enrichment of carbon in ferritic side b. Depletion of carbon in ferritic and enrichment of carbon in ASS side c. Carbon migration takes place from ASS to ferritic steel d. Softening of the weld zone 4. A metal having good weldability if its ductile to brittle transition temperature is a. Above the room temperature b. Below the room temperature c. Above the recrystallization temperature d. Below the recrystallization temperature 5. Hydrogen-induced cracking is not a big issue in the fusion joining of a. Low carbon steel b. High carbon steel c. Martensitic steel d. All of the above 6. Hydrogen-induced cracking is not a major concern if the weld joint is performed by the a. GTAW b. GMAW c. SAW d. SMAW 7. The machinability of steel is improved by the addition of a. Carbon b. Chromium c. Sulphur d. Nickel 8. With the increase in the percentage of manganese and silicon, the carbon equivalent will a. Increases b. Decreases c. Constant d. Depends upon the carbon percentage 9. Free machining steel is produced by the addition of a. P b. S c. Pb d. All of the above 10. Lowest amount of the oxygen content is usually present in the a. Killed steel b. Semi-killed steel c. Capped steel d. Rimmed steel  Assignment 11 1. Gas porosity can be formed when the rimmed steel is joined by a. Heat source of high heat input at very high welding speed b. Heat source of high heat input at very low welding speed c. Heat source of low heat input at very high welding speed d. Heat source of low heat input at very low welding speed 2. Generally, matching fillers are preferred in a. Butt weld joint configuration b. To compensate for contraction strain imposed during welding c. Fillet welding d. Overhead welding 3. Welding of medium carbon steel without pre-heating, leads to a. Formation of martensite in weld zone b. Lower cracking tendency c. Formation of ferrite in heat-affected zone d. All of above 4. To relieve the stress, stress-relieving treatment on the steel is carried out at a. Above the lower critical temperature b. Below the lower critical temperature c. Before welding of the plates d. In between lower and upper critical temperature 5. Pre-heat is not required for the welding of HSLA steel, if welding is performed by the a. Electro slag welding b. Electro gas welding c. Submerged arc welding d. All of the above 6. The possibility of hydrogen-induced cracking is higher in the welding of a. HSLA steel b. HTLA steel c. Low carbon steel d. All of the above 7. Carbon percentage in steel increases from 0.1, solidification cracking tendency in steel can be reduced if the manganese to sulphur ratio a. Increases b. decreases c. First decreases than increases d. First increases than decreases 8. Soft phase formation within the weldment and HAZ is desired so that a. Residual stress will be high b. Cracking tendency can be avoided c. Hydrogen content may increase d. Compressive residual stress may develop 9. During the welding of heat-treatable low alloy steel by fusion welding process, the conversion of austenite into martensite leads to the a. Residual stress formation b. Hydrogen induced cracking c. Embrittlement d. All of the above 10. With the pre-heating of HSLA steel a. Martensitic structure can be achieved b. Martensitic structure can be avoided c. Increases the residual stress developed d. Bainitic structure can be avoided  Assignment 12 1. If a steel plate has a higher thickness and carbon equivalent, then the required pre-heat temperature will be a. Higher b. Lower c. Below the room temperature d. Cryogenic temperature 2. Embrittlement of weld and heat affected zone of Cr-Mo steel results into a. Cracking b. Higher weld joint ductility c. Softening of the weld zone d. High toughness 3. Sensitization in Cr-Mo steel weld joint occurs due to a. Exclusion of C from Cr carbide b. Hydrogen embrittlement c. Softening of HAZ d. Formation of Cr carbide 4. Pre-coated steel is usually coated with zinc, called as a. Aluminized steel b. Galvanized steel c. German steel d. Fluorescence steel 5. For the resistance welding of aluminised steel as compared to bare steel, the current requirement is a. Higher b. Lesser c. Same d. All of the above 6. Generally thick coating on the galvanized steel can be achieved by a. Electroplating process b. Hot dipping process c. Lithography process d. All of the above 7. The chromium percentage in stainless steel is a. Less than 8% b. Greater than 8% c. Greater than 12% d. Less than 12 % 8. A phase stabilized by chromium is a. Ferrite b. Austenite c. Martensite d. Delta ferrite 9. Martensitic stainless steel of high carbon and low chromium content during welding with low cooling rate offers a. Higher residual stress b. Reduced toughness c. Reduced cracking tendency d. All of the above 10. Aluminized steel coated with Al and 8% silicon helps to improve a. Corrosion resistance b. Oxidation resistance c. Formability as compared to pure aluminium-coated d. All of the above