I have been watching this forum many time ago and this is the first time I write something. I hope to have more things to discuss since now :-)
In the image attahced, you will see a table of the mechanical properties of diferent types of steel. Is the usual table of any catalogue.
And there is one think that I don't understand. If you have a look at how either tensile strength or the yield strength changes according to the nominal thickness, you can see while the thickness increases, the value of its N/mm2 decreases. This fact seem's to be impossible because any bar or any object, the bigger it is, the higher stress it can sustain, but in the table tends to be lower everytime.
For example, the steel S235JR, with a thick of less than 3 mm can hold (tensile stress) between 360 and 510 MPa (N/mm2), and if it its thickness is between 3 and 100 mm it can hold between 340 and 470 MPa. Both intervals cover at some range, but the thicker one has a lower stress sustain. The same happens with the yield strength.
Might somebody help me with this question?
Thanks a lot!