ME364 exam 2 solutions - Exam#2 YEDITEPE UNIVERSITY...

Info icon This preview shows pages 1–9. Sign up to view the full content.

View Full Document Right Arrow Icon
Image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Image of page 2
Image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Image of page 4
Image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Image of page 6
Image of page 7

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Image of page 8
Image of page 9
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: Exam #2 (April 28, 2008) YEDITEPE UNIVERSITY Mechanical Engineering Department ME 364 MANUFACTURING TECHNIQUES H — “.1 SPRING Semester M \ Duration: 2H0urs @1. @ CLOSED BOOK, CLOSED NOTES Metalworking processes are clasified, according to process temperature as: (a). flinwac/th. ................. .. (b). Co/a’...(4/o.ckr}n_9 ................ .. and according to the amount of deformaion as: (c).3u/k..dg76pm2‘z.ba ........ .. (d). SAeefi...m.e72/. firth/hf . List some advantages and limitations of cold working: (a).fiagqus....hfi raffleJJ...¢z,q.a(.Jlltth-fé ................................ .. (b).blm.€nflb.nq /. . exam“. . fl.an ............................................. .. (c)..k5.‘D.’Ja//..;.pafi[email protected]/uédflé; ........................... .. (dykéguzms’.....mO,c..foa/¢c.. ................... .. (e). III-Wes. . . . . .mfixfizfla? - -/~ea/ac.«:.r. . . éomflim- 6/54”!qu mgncfi‘c f/O/efl‘fefi 3. List the processes utilized to make the part in (e) from the stock in (a). (a) (e5) (e) (a). . .. WSZIQCé .... .. (b). .firwamégx fluszbfl ...... .. (c). .Qna/amflflmion ...... .. (d). . . .acflidzbn. rot/95%}; (e). ........................... .. La) (b) 4. (a). In .-.v. e ...... .. forging, the quality of forging depends on the skill of the operator. Three-piece assembly shown in the figure below can be manufactured as one piece by employing the following main processes: 5. Fill in the following questions with INCREASE or DECREASE. (a). Increasing hydrostatic pressure around a work piece of metal during forming does not vary flow stress much, but .... .. the true strain of fracture. (b). In extrusion, shear resistance ......... .. linearly with semicone angle. (c). In extrusion, friction losses .. with semicone angle. The flow stress for cold work is given by a = K8” : (d). Cold working results in .. in the value of K. (e). Cold working result in me. In the value of n. 6. (a). When upsetting a rectangular workpiece, material always flow in the direction of . 845. f. #195. {4172/}.ch . . . (b). When designing a part for forging, considerations should be given to: .57m0.v.7.% . . . aY‘é/nkfl . f/Da) . . 4 [/QMflQfJ‘ . . .. Mag. .............. .. gonna/:5 ........................ .. chat/7’5} Mic/meg ofueéJ/ a2. 7. The cylindrical cast iron part with a cavity shown in the figure below is to be produced by sand casting. You are required to calculate the dimensions of a pattern to produce the part using face A-A as a parting line and having the axis of work piece vertical. Calculate the dimensions of the pattern including the machining, shrinkage, and drag allowances. Draw the final dimensions of the pattern. Use the following allowances: Machining allowance = 3 mm/side Draft allowance = 3 mm/m Shrinkage allowance = 1 mm/m Surfaces marked \l are to be machined. b v‘ v 3 t if... - , MM (910 L. W1 0‘ t» a ) y e ' 8. (a). What is the difference between machining allowance and dimensional tolerance ? MaCWm‘n allOwG/tctc fanm-(g3 HQ amoaA-i‘ of MerisQ 375 be Wing fin,“ max surface. Dix/enscoan Hem/ice m4sz Hie lzmzhhf W °¥ oitmengion after JrAé (Mousse:- (b). Why are steels more difficult to cast than cast irons? What is the consequence ofthis? Nel‘it‘ng Tcmfemmm cg Sffie( is .ktf'Aef MM 65°34 ref/Li’th wufa,) had/(hf W'f MDHC/W WW4 ) I’WOH GN qu'en‘aflndaw mecr-Hcs ) shrink“ an: (c). What are hot spots in casting? What is their significance in metal casting? What can be done aboutthem? bW/{lf ant/hf / mftw of [bu/er 600(1)?!) ADJZS EC ("4‘ WritiTomsh‘v 0AA sit/7th mix/7‘9 C044 dwl" (d). Whay are risers not useful in die casting as compared to sand casting ? Qatar—s etc was! [A W c4995» to mafia Ju/P— Haida/7’90 Loafing, motif/t man‘an‘ég wfa be at/zzf/aé/e 04 hov‘ 6179973.]? die wfi/‘y/ “so/{W mqfi/{d ,5 11-424 12: e Una/er Pva/c)PQ/r¢ [5 WOW afi‘ér Coo/ea/Uf’zg 7%57‘ W 76¢ Mar. 9. Describe the factor that inuence the magnitude of the roll force, F, as shown on the figure on the right. ’ RID/(6r did/W073) . Ro/l-sywp confide/f /&Ad,7cg . 60.1440“ oFae’ F: L'Q/o L‘flc Rikvit‘f) Torque - knew" . .de/mom Jafl(éos/¥> ' 10. Calculate the roll force, torque and the power required for a 304 stainless steel strip 150 mm wide and 8 mm thick and rolled to a thickness of 6 mm. The roll radius is 180 mm and rolls rotate at 200 rpm. 3o4—57‘mb/wtfa/ g - g“ .52 4. 3. G _ ltd-=18me k—F ko:gmm 2:0.23 125:6». fie) gator/Hi (are) _ pass”. ‘1(o.Zs)‘='717Mfi(53rW‘) Tat? = my?” = sir/ma )U=Zao 7"“ F: Ltd-H:leISDx§IS=M€3on6N P T3!" #1; ': lfiéxxtocx 0-315 _-, I331“. N.m oust-r —; 2‘1?” 1 2x133“I ,4 27Tme 6° = 581,069 (A) 2-5th KMJ @ ll. (a). Why is the intermediate shape of a part important in forging operations? /r\7émtc-.(tZ/7é 47%;» filo/Drove uni/4m” 7&0“) 07/ Wide/JAE, M @4127 27” rec/aw max [6’05 #63»th . (b). How would you tell whether a certain part is forged or cast? Explain features that you would investigate. /Q//‘7(5 Acwc. 3000/ JuF/gce .QW7- ’57 0M1 find @a/C/ 1e mnth/e Z6”) Deck/Ale and /” W5 v§60firvruj (c). What are the differences between open-die and impression-die forging? I?» o/en a’x'e fi/f/x‘r/ [WW/5‘06 [5 M74 Zflfizeen 7%: {/H 1/65. ,7/ 2t emf/e, Amt raga/m matan were“ . fl Mfr/Mm- aét'e mag/721 #@ Me Sth 3]; aye [at/57" ,A‘gciérca 6 (d). What is “flash”? Where is it important? Why does it matter ?‘ F/‘MA ('5 hams“; tofi't/vz/lc dire Cory/ofig,$D/ne 9% mack/{due flow: DLLW 4N /5 MHF/MA h‘w firearm: an! firs/W Magma Mam/Ice flawta,xNNc»Mwa%sM1mehflfiy%w Mfi;%uh 12. Calculate the forging force at the end of the stroke for a solid, cylindirical workpiece made of annealed 70-30 brass that is 100 mm high and 150 mm in diameter and is to be reduced in height by 25%. Coefficient of friction is estimated to be 0.25. Sketch the shape with dimensions before #313 and after forging. ~.——-—/ 5“” 9”“ m H°=IDO~~ - . Ram”. W H1 fiwbgmw Mint red. H74 ——"——~ H1: Hum-Q'Y'v 15M», ‘ tum “new bww stews 4% 76% \IO -: U‘ ) ’12 H‘) a TIP—'2“; 4 4f‘ :LIS‘DZ Dz loo = ~11 :932 2=Lm,0'29 5’ K f“ i575“ M” W 490 \i : 300 x 0.130”: WMRL. J52: “Wm—"e WQM ‘93 a» 20% 210211011 ———*i; =HFH6U 3x? 6 -: l.34?‘xl0 L6 18¢“- 13. (a). What is the difference between extrusion and drawing? 7:“ @W5;M/mqj:nr«£ air /)u54e¢/ #M #Lol/E. .Dw abath matriaz I} fut/£4 7%“ #2»:- (b). What is a “dead metal zone”? Mei! [A m Comeer W 63124 dot» A01" move/{imflar 74> 5725(na1432n140w {If ado.”an OF 5A“? 36696: or {If/U- (c). What type of defects occur in extrusion: Syfice GflCL‘J/Plfl “774 My, dc. Drawin : - g fér mac/49;», 55am; (flay/$41M sawed, Into/Me SW42, wQV/ft‘ja/c/C 14. Calculate the force required in extruding a workpiece made of Aluminum at 400 ° . Billet diameter is 200 mm and extrusion ratio is 3%. How did you account for frictional loss and die angle ? How would you evaluate your result? AQ 111092 P we he“ (A9.) 59:2090‘4» [ha-3:30 £4250 M?“ (R 6V") At 2 2 ’gikéy‘go :"f’xsvflwo a: : S.ZAZ.A\OQ L) w ‘5342. +0“. +fl‘jG’V‘ i4 acc * CW W“ “l? “43$” oi/tcawéw K k“ RAM. & 180 160 140 120 True stress (psi x 103) . Aluminum 1100—O 2024—T4 6061~O 6061—T6 70757—0 Brass .2 70—30, annealed 85—15, cold-rolled Cobalt-based alloy, heat-treated 2070 Copper, annealed Steel Low-C annealed 4135 annealed 4135 cold-rolled 4340 annealed ~ 304 stainless, annealed 410 stainless, annealed K (MPa) 180 690 205 410 400 909 '5—80 ,———~, 315 530 1015 1100 640 1275 960 0.20 0.16 0.20 0.05 0.17 0.49 0.34 0.50 0.54 0.26 0.17 0.14 0.15 0.45 0.10 8650 Steel 1112 CR Steel 0.2 0.4 400 03 O O) O l\) O Extrusion constant, kc (103 psi) A O 0.6 0.8 True strain (8) 600 304 Stainless steel 70—30 Brass, as received 1020 Steel 4130 Steel 2024-0 Al 1100-O Al 1.0 1.2 1.4 1.6 °C 800 1000 1200 a- 1500 2000 Temperature (°F) 70—30 Brass, annealed Copper, annealed 2024-T36 Al 1.8 1 400 2500 1 200 1 000 800 Pa 600 E V 400 200 0 2.0 ...
View Full Document

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern