Finite Analysis: Relation Between Hardness and Yield Strength

I would suggest doing an SEM on a fractured surface tested at various temperatures and correlating the properties. It will depend highly on microstructure and grain size.

The only way to find out the answer is through actual physical testing after various heat treating cycles to achieve the hardness you are looking for.

Tensile strength refers to the property to resist forces applied to pull it apart. tensile strength has two parts. Yield strength and ultimate strength. YS is the amount of strain needed to permanently deform a test specimen. Yield point is the point during tensile loading when the metal stops stretching and begins to be permanently made longer by deforming.

Ultimate strength is the measure of the kpa (psi or Mpa) load that breaks the specimen.

Hardness is the resistance to highly localised deformation. Hardness is affected by heating from the welds and also due to heat treatment methods. High hardness (high strength ) could indicate presence of un-tempered martensite in the weld HAZ while low hardness may indicate an over tempered condition. Welding may result in significantly lower HAZ of cold worked metal as a result of re-crystallization

Hardness is proportional to strength. It is a quick way to determine the strength. It is also a easy and useful method to determine whether the metal in question has received a proper heat treatment since heat treatment also affects strength..

Examples: yield & uts for 40 hrc, 45 hrc, 48 hrc, 50 hrc, etc if possible.

HRc ----- Mpa ----- tons/in²

60 ----- 2320 -----150

55 ----- 1990 -----129

51 ------1730------112

45 ------1450------ 94

41 ------1310 ------85

34 ------1110 ------72

30 -------970 ------63

20--------770------ 38

Trust above details will be of help to U.

Sridhar : advance Institute of welding technology – Chennai –India.

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