ME RME-081 Q3 02 JULY 2021 Nitesh gupta PDF

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SHRI RAMSWAROOP MEMORIAL GROUP OF PROFESSIONAL COLLEGES QUIZ TEST-III (Session: 2020-21)

B.Tech. VIII Sem. (ME-All Groups) RME-081: ADVANCE WELDING Duration: 01 Hour Maximum Marks: 60

Course Outcome: CO3- Provides knowledge to understand the heat flow in welding structure which could alter the properties of structure during designing and their uses.

Note: (a) This paper is divided into two sections. Attempt all questions in both the sections. (b) Section A contains 30 questions carrying 01 mark each. (c) Section B contains 15 questions carrying 02 marks each. Section A: In the below mentioned questions, the statements have only one correct option.

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Weld thermal cycle shows a. variation in temperature of a particular location during the welding as a function of welding time b. variation in temperature of a particular location c. variation in temperature of all location d. equal variation in temperature of all location in welding region In Weld thermal cycle, a. Temperature in y-axis,location in x-axis b. Location in y –axis,temperature in x-axis c. Time in x-axis,temperature in y-axis d. Temperature in x-axis, time in y-axis weld thermal cycle are not influenced by a. heat input rate b. amount of heat supplied for welding c. plate geometry d. thermal properties of base metal What does HAZ stand for? a. Helium Aerated Zone b. Heated Area Zone c. Heat Affected Zone d. Heat Allowed Zone What can we considered the HAZ area in welded Joint? a. Strongest b. Weakest c. Hardest d. Softest Which size of HAZ found during the Process with slow heating ? a. Small b. Large c. No effect on d. Randomized What this formula EIf/v represent? a. Total Heat

Date of Quiz Test: 02/07/2021 RME-081_Er.Nitesh gupta

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b. Net heat c. Heat Input d. Heat output The formula 𝑡√

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𝜌𝐶(𝑇𝑐−𝑇0) 𝐻𝑛𝑒𝑡

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is used to find:

a. The temperature of plate b. The cooling time of plate c. The thickness of plate d. The heating time of plate In cooling rate Calculation: Thin plate is to be considered, When a. Relative plate thickness is greater than 0.75 b. Relative plate thickness is greater than 0.85 c. Relative plate thickness is less than 0.75 d. Relative plate thickness is less than 0.85 Which of the following property is responsible for weld metal cracking? a. Stress b. Strain c. Temperature conditions d. Pressure conditions The property of a material which has the greatest influence on welding distortion is its? a. Yield strength b. Coefficient of thermal expansion c. Elastic modulus d. Coefficient of thermal conductivity Which method is not used to reduce welding stresses ? a. Hammering b. Peening c. Thermal treatment d. Vibratory stress relief What type of distortion is shown in the picture?

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a. Angular distortion b. Longitudinal distortion c. Longitudinal shrinkage d. Buckling distortion What causes distortion? a. Heating b. Cooling c. Uneven expansion & contraction d. Poor quality materials The photo opposite shows

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Date of Quiz Test: 02/07/2021 RME-081_Er.Nitesh gupta

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a. b. c. d.

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Balanced welding Skip welding Tack welding Intermittent welding

Who derive analytical equations for heat flow during welding?

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a. Adams b. Kou and li c. Computer simulation d. Rosenthal In an arc welding process, the voltage and current are 25 V and 300 A respectively. The arc heat transfer efficiency is 0.85 and welding speed is 8 mm/sec. Determine net heat input (in J/mm) ? a. 64 b. 797 c. 1103 d. 79700 Preheating a low alloy steel prior to welding to minimise the risk of: a. Porosity b. Excessive distortion c. HAZ cracking d. Lack of fusion Fillet weld produces smaller HAZ than butt welds. a. True b. False c. Sometimes True d. Sometimes wrong Welding procedures may require welds to be deposited at a controlled rate of heat input. High heat inputs would: a. Have poor profile b. Have larger grain size c. Have high hardness in the HAZ d. Have low elongation properties If thickness of plate is 1, it is reagarded as what? a. Thin plate b. Thick plate c. Both condition of thick and thin may be applied d. None of the above Isochromatics are best related to: a. color bands give the directions of principle stresses b. color bands give the directions of maximum shear strain

Date of Quiz Test: 02/07/2021 RME-081_Er.Nitesh gupta

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c. color bands give the directions of principle strain d. color bands give the directions of maximum shear stress When welding thin plate distortion can be minimised by? a. Welding from both sides b. Using U preparations rather than V types c. Using strongbacks d. Using back-step welding What does PMZ stand for? a. Permanent Melted zone b. Partially melted zone c. Passive melted zone d. Porous melted zone Which is the hardest structure of iron carbide diagram ? a. Ferrite b. Pearlite c. Cementite d. Martensite In which one of the following welding processes, very slow cooling rate should be followed to avoid cracking? a. Glass welding b. Plastic welding c. Welding of stainless steel d. Brazing of ceramics Which relates with Reducing the amount of weld metal in joint ? a. Reduces the amount of distortion b. Reduces the capability of the joint c. Reduces the quality of the joint d. Reduces the design of the joint Epitaxial growth and nucleation are one and same thing found during: a. Cooling b. Solidification c. Welding d. Soaking The magnitude of recation stresses is proportional to a. Length of material b. Inverse of length of material c. Square of length of material d. Inverse of square of length of material What is the purpose of tacking in the job? a. to obtain penetration b. for controlling of distortion c. to save the gas consumption d. to increase the production

Section B: In the below mentioned questions, the statements may have more than one correct option(s): At any temperature T,𝑘 = 𝐶𝐿

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𝐶𝑠

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,k is known as

a. Ratio of CS and CL are the compositions of the solid and liquid b. equilibrium partition ratio

Date of Quiz Test: 02/07/2021 RME-081_Er.Nitesh gupta

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c. equilibrium segregation coefficient d. thermal conductivity Weld thermal cycle curve is best represented as: a. Steep increase b. steep decrease c. gradual increase d. gradual decrease Which of the following are integral components of welding processes? a. Heating b. Melting c. Cooling d. subliming Processes which have high rate of heat input ? a. Gas Metal Arc welding b. Plasma Arc welding c. Laser welding d. Submerged Arc Welding The slowest cooling rate is obtained when steel is quenched In which? a. Furnace b. Room temperature c. Normal air d. Water The extent of constitutional super cooling in a given alloy depends on : a. The conductivity of liquid b. The temperature gradient in liquid c. The rate of growth d. The rate of decay Stresses in welds are produced due to : a. Mechanical Residual stresses b. Metallurgical Residual stresses c. Torsional stresses d. Reaction Stresses Lamellar Tearing is due to a. Very severe restraint on the joint b. Poor ductility c. Presence on non metallic inclusion running parallel to the plate surface d. None of the above How can we prevent the Transverse contraction ? a. Reduce the angle b. Proper tack welding c. Proper weld position d. Increasing the arc travel speed What are the types of Distortion? a. Longitudinal shrinkage b. Transverse shrinkage c. Angular shrinkage d. Line shrinkage The size of the heat affected zone will increase with a. Increased starting temperature

Date of Quiz Test: 02/07/2021 RME-081_Er.Nitesh gupta

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b. Decreased welding speed c. Increased thermal conductivity d. Decreased base metal thickness

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To maintain close control of the thermal cycle, Which of the following is necessary to obtain a heat affected zone with good microstructure? a. pre-heat b. weld heat input c. post-heat d. Cooling 1/(tρ-to) =(4.13ρchY / Hnet) + (1/(tm-to)) expression is used to calculate what? a. Solidification time b. Width of haz c. Plate thickness d. Peak temperature The parameter which has no effect on cold cracking of a shielded metal arc weld is : a. cleanliness of the job surface b. baking of the electrode c. preheating the job d. excessive weaving of the electrode How can we control the distortion, from the following ? a. Keep the contraction force as low as possible b. Post heating is done c. Place welds near the neutral axis d. Use backstep welding

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Date of Quiz Test: 02/07/2021 RME-081_Er.Nitesh gupta

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