1.a. List the primary criteria for material selection in manufacturing operations.
b. Sketch the stress-strain curve for a typical material. Indicate on the graph the, i) plastic and elastic zones, ii) UTS and yield stress, iii) necking region, iv) and an indicator for E.
c. A 40 mm diameter steel column is 3 meters long. It carries a tensile load of 72100 N. Given that the modulus of elasticity for steel is 200 GPa, calculate (i) the tensile stress and strain and (ii) by how much the column is extended.
d. A2meterlongand3mmdiameter4340SteelRodundergoesatensiletest.Attheendofthetest the rod extends by 1.25 mm. For 4340 Steel K = 640 Mpa and n = 0.15. Using true stress and true strain, determine the final load applied in the tensile test.
2.a. There are three atomic arrangements found in the crystal structure of metals. List, and sketch each of these arrangements.
b. Intheformationofalloystwotypesofsolidsolutionsarepossible,substitutionandinterstitial. Briefly differentiate between the two.
c. Sketch a phase diagram, and identify what information it provides about the composition of melting alloys ?
3.a. Define and differentiate between primary, secondary and finishing production processes
b. A simple estimation for the roll force is given by F=LwY. What is L? Derive an expression for L from the geometry of the rolling process.
c. A 40 inch wide 6061 Aluminum sheet is rolled from 0.25" to 0.15". The roller radius is 20". For 6061 Aluminum k=60000 psi, and n=0.05. The factory has a 4500 HP motor driving the two rollers. At what RPM must the rollers be set for this operation ?
4.a. Identify and sketch any two types of work holding we see in lathe operations.
b. Listanddefinetheprimaryspecificationswhichareusedtocharacterizealathe.
c. A high-speed cast iron bar 8 in diameter is being machined on a lathe. The depth of cut is 0.050 inch and the spindle rotates at 450 RPM. The width of the cutting tool is 0.16 inch. The specific energy for machining high-speed cast iron is is 1.18 HP.min/cubic-inch. What is the cutting force ? What is required cutting power in Horsepower? 1 HP = 33000 ft.lbs/min
5.a. Draw a sketch of the punching process and label the (i) punch (ii) die (iii) slug (iv) sheet, and (v) the clearance
b. Explainandillustratetheconceptofprogressivediesasappliedtosheetmetalforming
c. What is likely to happen if the minimum bend radius is violated in a bending operation.
d. Amildsteelsheetwiththicknessof0.045inchisbenttoaradiusof4.05inch.Giventhatformild steel the yield stress is 24,000 psi, (i) calculate the radius of the part after springback. (ii) If the initial bend angle is 24 degrees what is the final bend angle? For mild steel E = 38.54 Mpsi.