So I have an exam (please read!)

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Hi all, I am a university student in engineering and I am taking a Joining class this semester (which means it's 99% about welding). We have been given a take-home exam and the questions are pretty obscure & tough. I'm hoping some of you might be able to help! This isn't cheating, the prof has recommended we join online forums for a previous exam! I will also be heading to the library, but the info he's looking for is the kind of knowledge that comes with experience (of which I have none). It's due this coming Tuesday, the 18th of March. I'll post the questions as they appear as soon as I have more time. Sound like a challenge? You'll see...
Reply:that seems weird that he is looking for answers that come from experience from students... isn't that a contradiction?anyway... I'll try to help you out when you get a chance to post some of them.The Welder Shop has great deals and reviews on Hobart, Miller and Lincoln Welders.
Reply:Question 1.A.Sketch and label all the microstructural zones you would expect to find for a fusion weld made between a piece of annealed pure copper and a piece of heavily cold worked 70Cu-30Zn yellow brass. B.Show the relative sizes (i.e. widths) of the various zones in each piece.C.Draw the hardness profile across the weld, i.e. form the Cu side to the brass side.D.Explain how such a weld assembly would fail during a tensile test.Question 2.Steel containing Mn and Si is welded. Based on the following reactions, explain why the concentration of Mn and Si is likely to be lower at the surface of the weld region. Assume a temperature of 1600oC in the liquid metal and use the Ellingham diagram for data.SiO2 + 2Fe = Si + 2 FeO2Fe + O2 = 2 FeOSi + O2 = SiO22 MnO + 2 Fe = 2 Mn + 2 FeO2 Fe + O2 = 2 FeO2 Mn + O2 = 2MnOQuestion 3.Estimate the weld-pool radius in 1040 steel and the distance from the heat source at which martensite would be expected to form. Assume a static electrode heat source supplying 400 A at a voltage of 18 V. For the 1040 steel assume a heat transfer coefficient of K = 41 W/m*K. List any assumptions you have made in arriving at your estimate.Question 4.Explain the term partition coefficient. How does the partition coefficient affect the formation of the microstructure in the weld region.Question 5.A.Using the TTT diagram provided, which is for an eutectoid steel, determine the microstructure of the heat affected zone if a cooling rate of 0.1 oC/sec, 75 oC/sec and 300oC/sec, respectively, is imposed.B.Construct the CCT diagram for this steel starting from the provided TTT diagram. (draw the CCT diagram on the provided TTT diagram, so I can superpose your answer with the solution).C.Using the CCT diagram you developed, determine the microstructure of the heat affected zone if a cooling rate of 0.1 oC/sec, 75 oC/sec and 300oC/sec, respectively, is imposed. Ellingham diagram associated with Question 2. TTT diagram associated with Question 5.
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Reply:Sorry, but I think you're in deep, deep trouble. That stuff is beyond me. I can weld but some of that stuff looks like it's in a foreign language, like Martian?
Reply:you lost me after: "I am taking a Joining class...". sorry man, but i don;t think too many people will be able to help you. however, there are some pretty technically-smart people on here... the first on that comes to mind is Pulser. send him a PM and maybe he can help. i'm not promising that he will be able to, but he'd be my first stop. from the sounds of those questions, you are not an undergrad student... NO OFFENSE TO ANYONE HERE, but your "average" to "above-average" welders probably won;t have a clue what you are talking about here. i think the kind of experience you are looking for is more from a Welding Engineer, rather than a welder.sorry i couldn't be more of a help.Later,Andy
Reply:Sounds like cheating to me.Hobart 140 Handler w/ gasHyperTherm Powermax 380 Plasmaoxy/acetylene
Reply:Originally Posted by Rick MoranSounds like cheating to me.
Reply:That's undergrad level engineering coursework.Look it up.  Asking a forum for tech grain structure diagrams and such isn't usually going to work.And in the real world, 400A of welding current usually takes more than 18V.  More like 36 volts!
Reply:OK,For starters, this is probably not the forum for you.  That said, there are a few people here, myself, Pulser, and a couple others who probably could answer these questions.  But, I'm not doing your test for you.  Not unless you meet 2 conditions.  One, you post the name and email address for your professor, and I can hear from his own mouth that having me do your test is OK.  Two, you compensate me for at least 8 hours worth of investigation time it would take me to dig up all the info needed to completely answer all the questions you posted.How about this, you try to do your own test, and if you have specific questions, that you simply cannot answer, post them here.  If you want an opinion on the accuracy and thoroughness of one of your own answers, post it here, and I'll be glad to give you my opinion.  I'm sure the others who are knowledgeable would be happen to contribute under these conditions as well.I suggest you hit the books, cause I figure you've got a pile of work to do before the 18th. Originally Posted by NatmanHi all, I am a university student in engineering and I am taking a Joining class this semester (which means it's 99% about welding). We have been given a take-home exam and the questions are pretty obscure & tough. I'm hoping some of you might be able to help! This isn't cheating, the prof has recommended we join online forums for a previous exam! I will also be heading to the library, but the info he's looking for is the kind of knowledge that comes with experience (of which I have none). It's due this coming Tuesday, the 18th of March. I'll post the questions as they appear as soon as I have more time. Sound like a challenge? You'll see...
Reply:I didnt have courses involving that information when I was an engineering major and I haven't learned any of that as a welder either.   Sounds like something someone in metallurgy would need to know.   I'm all for learning stuff but I don't see where a welder needs to know all that.MM350P/Python/Q300MM175/Q300DialarcHFHTP MIG200PowCon300SMHypertherm380ThermalArc185Purox oaF350CrewCab4x4LoadNGo utilitybedBobcat250XMT304/Optima/SpoolmaticSuitcase12RC/Q300Suitcase8RC/Q400Passport/Q300Smith op
Reply:DesertRider33,You're right on the money.  The questions posed are exactly the sort of things they teach in undergraduate Materials Engineering/Metalurgy/Welding Engineering programs.I was having cold sweats and flash backs to 15 years ago, and my own time at college,  after reading his post.
Reply:Ok so I didn't mean to scare anybody. It's true, I'm in a metallurgical engineering program. And for the record it sounds like bullcrap to me too! The course material barely covers most of this stuff, which is why we were given a take-home exam. We're expected to look it up & find the answers any way we can. I definitely don't want anyone to do the exam for me, just see if any of the info makes sense to you, get me pointed in the right direction. Like dissimilar metals must be a pain to weld? But it's cool if this isn't the best forum to ask, it was a stab in the dark. Now I get to hit a library full of books in which I don't know where to find the answers.
Reply:Two books that might help - "Design of Weldments" & "Design of Welded Structures". I don't know if they will help and don't feel like doing research right now, though I had done plenty by the time I finished 2 degrees, lol. Another good place to look for info on the web would be Lincoln Electric's knowledgebase. Might take a while to wade through it, but a lot of good info there. I'm not an engineer, but I am pretty sure there are engineering references out there with this info in them and I am pretty sure that is your instructors purpose in giving you this. Probably an engineering forum or two out there as well.The difference between art and craft is the quality of the workmanship. I am an artist.
Reply:Question 1.A. Sketch and label all the microstructural zones you would expect to find for a fusion weld made between a piece of annealed pure copper and a piece of heavily cold worked 70Cu-30Zn yellow brass. What The Fizzle! Who wants to fusion weld annealed pure copper to heavily cold worked 70Cu-30Zn yellow brass anyway? What for? The pure copper is softer than the work hardened brass, the weld zone introduces more hardening into the bead and reaching into the HAZ. The soft copper gives way to harder copper at the edge of the HAZ, then the bead itself would be the hardest portion(me thinks). The haz once again gives way too the slightly softer work hardened brass. This is all conjecture, but go ahead and quote me!! Sorry, I got my own homework to get back to.  RotsaRuck!City of L.A. Structural; Manual & Semi-Automatic;"Surely there is a mine for silver, and a place where gold is refined. Iron is taken from the earth, and copper is smelted from ore."Job 28:1,2Lincoln, Miller, Victor & ISV BibleDanny
Reply:Natman,Go ahead and post after you make an attempt at answering the questions on the test on your own. Don't just flop the whole test up here and expect us to fill in the blanks.  That's not going to help you learn how and where to find this stuff out on your own, in the event you need answers to these sorts of questions on the job.While the details of your professor's test may be gibberish, the exercise in finding the answers will teach you where to find the answers to real world questions.If you're completely lost, I recommend starting with the ASM handbooks (ASM = American Society for Materials).  These are a series of large engineering references that cover all aspects of materials and manufacturing technologies.  I know there are volumes on Ferrous and non-ferrous metallurgy and a volume on welding. Check out volumes 1, 2, 3, 6, and perhaps 9.   Here's a link to the ASM bookstore, so you'll know what you're looking for in your school's engineering library.  http://www.asminternational.org/Cont..._Handbooks.htmI know for a fact that all the answers you need aren't contained in these books.  I'll bet that there's enough there to get you a passing grade on your exam.  They should also give you a strong enough working foundation to go forth and find the more in-depth info.  Most of the text is in plain english that any undergraduate engineering student can understand.  Each chapter of each book also contains a list of pertainant references that will lead you to more info.At the risk of preaching, try to think of this as an exercise in learning how to learn.  Logical thinking and problem solving will be the most valuable thing you'll learn in college.  I think(I hope) that's part of the exercise your professor is trying to give you with this exam. Originally Posted by NatmanOk so I didn't mean to scare anybody. It's true, I'm in a metallurgical engineering program. And for the record it sounds like bullcrap to me too! The course material barely covers most of this stuff, which is why we were given a take-home exam. We're expected to look it up & find the answers any way we can. I definitely don't want anyone to do the exam for me, just see if any of the info makes sense to you, get me pointed in the right direction. Like dissimilar metals must be a pain to weld? But it's cool if this isn't the best forum to ask, it was a stab in the dark. Now I get to hit a library full of books in which I don't know where to find the answers.
Reply:same... sound like a backdoor solution searcher... no short cut I think... Attached ImagesUnit in my fab shop dept:my good hand and team that trust me...A lone welder make art... a village full of welder make Miracles...
Reply:Try: http://www.hybridburners.com/documents/verhoeven.pdf for some help with the last problem
Reply:awwww man H3LL  I'M GONA FLUNK THIS TESTgoodluck
Reply:Mom always said it wasn't a waste of a day if you at least learned something.Well I just learned that I don't understand anything beyond Hi I'm a university student.My Photos on Flickr
Reply:Sorry , but i didn't understand any of those questions.Way to much for me. Try some welding text books , or some other forums. If you ever do find out the answers , let us know. I'm interested in someone explaining them.
Reply:Well as mentioned this forum is more about hands on and actual welding.  Probably be better to look for an engineering forum is possible.  I would venture to say no one here could answer those from there head.  I had some engineering in college, and my father had an engineering degree.  I could probably look up the info in some old text books, but just don't have the time.  Like I said, look for an engineering forum and/or hit the books.I'm a Lover, Fighter, Wild horse Rider, and a pretty good welding man......
Reply:Jolly Roger's post seems like a good place to start.  You will find much better information in engineering handbooks for this sort of thing than in a forum.In my own engineering education (Chem E) our senior design problem was to design an ethylene recovery plant. Other than the US Bureau of Standards data  books, everything you needed (processes, equations, economics and all) could be found in the Perry Chemical Engineering Handbook.  Of course, it took 2/3 of the semester before most of us figured that out.
Reply:Those are some pretty tough questions for any of us not currently studying metallurgy, but I assume the instructor/professor has gone over these topics and that you are working with a text book that addresses these questions.
Reply:You can try posting your questions at the American Welding Society website at AWS.ORG.  They do not take kindly to helping students with their homework though.  They might tell you to do your own work if they figure out you are doing a test.  They have a lot of welding engineers and metallurgists though.  Does your prof really intend for you to get the "answers" form a web "forum", or does he want you to use web resources?  It is not fair to expect you to use web resources because many are not free.  I have a hard time at work getting some research papers because our budget will not buy them for me.Thanks everybody for having a look. We're not sure what the prof is thinking. This stuff is really not mainstream at all, best I found was a welding design book, where he probably got a couple of the questions from. Sadly we don't have an assigned text for this course. It will be fun to see what the class average is because I have seen all kinds of answers from the other students! The consensus is that the CCT diagram of question 5 is the favorite. I do have a pretty good idea on what to do for most of the questions, which should definitely be enough to pass. It's only worth 15% of the semester FWIW.