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  • GJS-600-3 - Wohler's fatigue curve

    Discussion in 'Calculations' started by Kaka_89, Dec 5, 2014.

    1. Kaka_89

      Kaka_89 Member

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      Hello,

      I need some help about the Wohler's fatigue curve. Nowhere in web I can not find any curve for Ductile Cast Iron mean GJS-600-3 (GGG-60). I need this because now i am calculating a chaotic stress life of journal of press modul to paper machine in the notch critical places.

      Please help, i repay for this.

      BS
      Kaka_89
       
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    3. CPPMable

      CPPMable Well-Known Member

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      Did a quick search for you doesn't look like there are many curves freely published available. Not that I seen in a quick 5 min search through my highly used channels. However, if you work or go to a school with access to www.sciencedirect.com there are multiple very good papers with the curves you are interested. Unfortunately, I won't break any copy right laws and post them here for you....sorry!

      If you are in industry go to the stock material supplier they should be able to provide you with something. If this is for school purpose there are many other types of ductile iron curves readily available which should provide a fairly consistent result as long as you make sure the micro-structures are similar.
       
    4. Kaka_89

      Kaka_89 Member

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      You write that you were looking less than 5 minutes and you find curves for GGG60. Please show me direct links to these websites. I will be grateful.

      I need that to my thesis.

      I know there is many ductile cast irons with similar properties, but the change is not viable due to the cost of intermediate.

      Seeking further.

      Yours sincerely.

      Kaka_89
       
    5. PierArg

      PierArg Well-Known Member

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      Hi Kaka and welcome to this great forum!

      What you are looking for is rather difficult (or impossible:cool:) to find: the fatigue limit depends by many factors that you have to consider during the design.
      As you know, the Wohler curve is representative of a circular specimen Ø20 mm subject to rotating bending and with a particular shape and surface finishing.

      But, what if you need to deal with different working conditions? The answer is: you have to introduce the corrective factors that bring you to define the "MODIFIED Wohler Curve"
      These factors are:
      - surface finishing (rough surface, polished, rolled, etc?)
      - type of load (rotational bending, alternate axial load, etc)
      - temperature
      - dimensions
      - safe reliability percentage (50%, 90%, 95%, 99%, 99,999%?)
      - material notch sensitivity
      - stress concentration factor
      - etc

      I don't know if you are a university student, but I can say there are many university books that discuss on this topic.
      The most important authors are Shigley and Juvinal and they explain how to create the "Modified Wohler Curves" for all materials.

      In my work I deal with fatigue analysis every day....so I decided to realize a simple excel worksheet.

      If you want I can post the GJS 600 modified Wohler curves. Is there anyone that can explain to me as I can post the image?

      Thanks


      P.S: sorry for my bad english
       
    6. Lochnagar

      Lochnagar Well-Known Member

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    7. PierArg

      PierArg Well-Known Member

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      Hi Lochnagar,

      thanks for your help :D

      As I understood, the only way for posting files is through a hosting site.
      I never used ImageShack and it requires the registration. Is the registration free?
       
    8. Lochnagar

      Lochnagar Well-Known Member

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      Hi PierArg,

      I used Photobucket - and that site was free - as you will see in the link below. It is a bit of a tedious process - capturing your picture and saving it on your computer - then uploading it to Photobucket - then copying the link address in Photobucket when you are prompted to so when you click on the image icon above - when you want to put a picture on this Forum.
      It would be nice if there was a quicker way:)

      http://www.photobucket.com/

      Hope this helps.
       
      Last edited: Dec 10, 2014
    9. PierArg

      PierArg Well-Known Member

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      The problem is that now I'm writing from the office pc and the company provider blocks some internet sites...among which photobucket :mad:
       
    10. PierArg

      PierArg Well-Known Member

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      In the meantime I want to correct an inaccuracy I wrote in my previuos post: the specimens used by Wohler during his tests were Ø7.5 mm and not Ø20 mm.

      Just to be correct
       
    11. Lochnagar

      Lochnagar Well-Known Member

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      Hi PierArg,

      Damned cookies - I posted the wrong link above - so I have corrected it above which might have caused you the problem:(
       

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