Page 1 of 7A Name: _____________________________Roll No.____________ TA201 (Manufacturing Processes) Sec No__________ Date: April 28th2015Max Marks: 120 I.[3 marks each] Answer short question (not more than few words) Q1. Name two Japanese Automobile manufacturing companies. Q2. What joining process would you use for these (eg. brazing, adhesive joining etc.)? i. Joining two metal rods for window frame ii. Joining a thin stainless steel tube to another thin stainless steel tube carrying gases at 500C Q3. Name two mechanisms by which adhesive joins the two adherands: Q4. Give one word for each of these i. Rate of straining which is directly related to speed of deformation ii. What is m in Yf = Cm Q5. What is the minimum temperature required for hot working of Aluminum whose melting point is 660C Q6. A round disk of 150mm diameter is to be blanked from a cold rolled stainless stripof thickness 3.2 mm whose shear strength =310MPa. Given that Ac = 0.075, appropriate punch diameter should be . 1.Honda,Nissan, Suzuki, Toyota, Acura 2.Mazda, Mitsubishi, Infiniti, Subaru, Lexus i.Welding ii.Brazing 1.Chemical Bonding, Physical interaction 2.Mechanical interlocking i.Strain-rate ii.Strain-rate sensitivity exponent ANS~194C (190-200) ANS149.52 mm (149.5 mm) Note: 1. Write your name, roll no. and section no. on each sheet2. There is no partial grading. For multiple choice questions, all correct choices must be selected, to get credit. (Dont just tick the option, clearly write the options in the space provided, eg. a, c etc) 3. Use of any unfair means would result in automatic Fail grade 4. Absolutely no sharing of pen, pencil, eraser, calculators etc. is allowed 5. If you have to leave the examination hall for restroom or bathroom break, you must submit your answer-sheets to the invigilator and then collect it back when you return to examination hall Page 2 of 7A Name: _____________________________Roll No.____________ TA201 (Manufacturing Processes) Sec No__________ Date: April 28th2015Max Marks: 120 Q7. Answer in one word: i. An application where addition of ceramics in metal matrix is useful ii. An application where component of high melting material is manufactured using P/M technique iii. Powder of ceramics of brittle metals is produced by this method where they are rotated inside a large jar and broken by impact Q8. Match the plastic components which respective manufacturing processes (Plastic injection molding, Blown film extrusion process, Plastic extrusion process) Plastic ComponentsManufacturing Processes Polyethylene bagsBlown film extrusion process Plastic rodPlastic extrusion process Plastic gearsPlastic injection molding II.[3 marks each] Objective type questions (More than one option may be correct) Q1.With increase in carbon content of steel, which of the following usually increases? (a) Tensile Strength(b) Hardness(c) UTS(d) Ductility Q2. Which of the following are fusion welding processes? (a) Manual metal arc welding (b) Brazing (c) Soldering (d) Oxy-acetylene welding (e) Diffusion welding (f) Resistance welding Q3. Which of the following are not sand casting related processes? (a) Pattern making(b) Sand making(c) Mixing metal particulates(d) Core making (e) Joiningi.Cutting tools ii.Tungsten or filament iii.Ball milling Ans: Ans: Ans: Page 3 of 7A Name: _____________________________Roll No.____________ TA201 (Manufacturing Processes) Sec No__________ Date: April 28th2015Max Marks: 120 Q4. Single most important difference between brazing and welding (a) Strength of joining is very different for the two processes (b) Base metal melts in welding, but not in brazing (c) Temperature of joining is higher in welding and lower in brazing (d) Welding is done for similar materials, while brazing can be done for dissimilarmaterials (e) Filler material in welding has composition similar to base metal, while in brazing, it can be very different Q5. RHW is given by f1f2RH. In oxy-acetylene welding process (a) f1 is high, f2 is low (b) f1 is low, f2 is high (c) both f1 and f2 are high (d) both f1 and f2 are low (e) f1 is low (f) f2 is low (g) f1 is high (h) f2 is high Q6. Which of the following are true regarding Diffusion Welding? (a) Diffusion welding takes places by fusion of the material at the surfaces (b) The process involves deformation by pressure near the faying surfaces (c) A solid filler metal may or may not be inserted between the faying surfaces (d) Metallurgical purity of the joining surfaces is maintained in this process (e) Diffusion welding can only be applied for joining similar materials Q7. Which are the advantages of Brazing over Welding? (a) Even dissimilar metals can be joined (b) Thin walled parts can be joined (c) Filler metal is not required (d) Less heat and power requirements (e) Less HAZ problem Q8. What parameters in metal forming are influenced by temperature? (a) strain-rate (b) K (c) n (d) ductility Q9. Advantages of powder metallurgy: (a) Versatile and used in numerous industries (b) Eliminates or minimizes machining (c) Minimizes scrap (d) Close dimensional tolerances (e) Manufacture of complex shapes (f) Excellent repeatability Ans: Ans: Ans: Ans: Ans: Ans: Page 4 of 7A Name: _____________________________Roll No.____________ TA201 (Manufacturing Processes) Sec No__________ Date: April 28th2015Max Marks: 120 Q10. During fusion welding, which is preferable (a) high power density and high energy (b) high power density and low energy (c) low power density and low energy (d) low power density and high energy Q11. Which of the following are true for both brazing and soldering? (a) Filler metal is not used for joining (b) Filler metal melts but base metal does not (c) Metals with poor weldability can be joined (d) High strength is not a requirement (e) It is a temporary joint Q12. Purpose of fluxes in brazing: (a) Facilitate wetting (b) Reduce the melting temperature of the base metal (c) Protect the joint until the solidification of the filler metal (d) Increase the strength of the joint Q13. In manufacturing, the purpose of property-enhancing operations is(a) improve physical properties without changing shape (b) to clean, treat, coat ordeposit material on exterior surface of the work (c) alter the geometry of the starting work material (d) material removal to give final shape Q14.Single most important difference between steel and cast iron is: (a) Nickel and chromium content in cast iron is very low (b) Mn is added in steel for strength and hardness (c) Carbon content in steel is less than approx 2%, while for cast iron it is higher than 2% (d) Si is added in cast iron as deoxidizing agent (e) Phosphorus content is very different in steel and cast iron Q15. Cores should possess which of the following characteristics (a) strength (b) permeability (c) ductility (d) toughness (e) thermal stability Ans: Ans: Ans: Ans: Ans: Ans: Page 5 of 7A Name: _____________________________Roll No.____________ TA201 (Manufacturing Processes) Sec No__________ Date: April 28th2015Max Marks: 120 III.[8 marks each] Draw Schematics Q1. Schematically show(a) Spot Welding (b) Groove Welding (a) (b) Q2. If you want to join two thin tubes by soldering, you need to provide it some additional strength. Draw a schematic to show how you would give additional strength to the joint. Page 6 of 7A Name: _____________________________Roll No.____________ TA201 (Manufacturing Processes) Sec No__________ Date: April 28th2015Max Marks: 120 Q3. Draw a schematic of density versus compaction pressure for ceramics. Clearly show axes labels Page 7 of 7A Name: _____________________________Roll No.____________ TA201 (Manufacturing Processes) Sec No__________ Date: April 28th2015Max Marks: 120 IV.[10 marks each] Numerical Problems Q1. A heat source is capable of transferring 3000W to the surface of a metal part. The heat impinges the surface in a circular area, with intensities varying inside the circle. The distribution is as follows: Cumulative Power inside circle of diameter x is given by CP (in Watts) = 300 + 4.32*x2, where x is in mm, for x25mm and CP=0 for x>25mm. What is the diameter of the circle inside which melting will occur? Ans: 9.17 mm (9.1 to 9.2) Q2. A tensile test is performed to determine the parameters: strength constant C and strain-rate sensitivity exponent m, for a certain metal. The temperature at which the test is performed = 500C. At a strain-rate of 12s-1, the stress is measured as 200MPa and at a strain-rate of 250s-1, stress is measured as 300MPa. Give the values of C and m with proper units. C143 MPa.s m0.13 Q3. A strip (300mm wide and 25mm thick) is fed through a rolling mill with two powered rolls each of radius = 250mm. The work thickness is to be reduced to 22mm in one pass at a roll speed of 50 rev/ min. The work material has a flow curve defined by K=275MPa and n= 0.15, and the coefficient of friction between the rolls and the work can be assumed to be 0.12 i. Determine the maximum possible draft for the given coefficient of friction ii. Calculate contact length between rolls and the sheet for the reduction from 25mm to 22mm. iii. Determine force on the rolls for such deformation iv. Calculate the torque required for each rollv. Calculate power requirements for the motor to move the two rolls. i.3.6 mm ii.27.38mm iii.1.44 MN iv.19,760 N-m v.206,900 Watts