I would like to know which steel is used for CHC class 12.9 bolt DIN912 (i am looking for the young modulous & poisson ratio of the material).

Thanks a lot.


  • 2
    $\begingroup$ I would be very surprised if I found out that the standard demands a specific steel. In any case, the steels that can be used for a 12.9 bold should not exhibit any significant differences in Young's modulus. If there is any change, it should be on the Poisson ratio, however even there it should be in the range between 0.27 and 0.31. $\endgroup$
    – NMech
    Nov 25, 2020 at 9:07
  • 1
    $\begingroup$ It could be an alloy steel equivalent to ASTM F568M (ISO898-1). If so, its properties can be found here. steelestores.com/grade/astm-f568-class-129-astm-f568m.html $\endgroup$
    – r13
    Aug 22, 2021 at 20:57

2 Answers 2


I found this : https://www.fullerfasteners.com/tech/steels-for-screws-bolts-and-studs/

So I used 37CR4 and I found density & young modulous here : https://steelselector.sij.si/steels/37CR4.html

  • $\begingroup$ Steel is steel; in this application about the only difference is strength . The influence of alloy is on hardenability . Hardenability determines how fast it must be quenched and how large the diameter can be ( for full hardness ) ; then alloy affects tempering temperature. Bottom line , all steels of strength "X" have very similar properties regardless of particular alloy . $\endgroup$ Dec 25, 2020 at 20:44

I think all the DIN standards are now ISO. Here are references I found:

Corresponding ISO standard, primary source -- ISO 898-1:2013

PDF copy of ISO 898-1:2013 from google search

To indirectly address the OP question, see document sections 6 (Materials), and 7 (Mechanical Properties).

The document specifies a a bunch of of properties like strength and hardness, but not Young's modulus or Poisson ratio -- although these are implicitly constrained by the material composition as per NMech's comment above.


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