Indentation hardness correlation to yield and tensile strength of mild steel
Indentation hardness correlation to yield and tensile strength of mild steel
(OP)
I understand that indentation hardness testing (using small hand-held equipment) in the field has a linear correlation to tensile strength.
For steel sections typically used in buildings and bridges, for example, say a wide flange mild steel section, is there a comparison table available between hardness values (Rockwell, Vickers, Brinell etc) to YIELD and TENSILE strengths?
If so, it is sufficiently accurate to determine if the steel is say grade 36 ksi or grade 50 ksi without having to take a field sample and lab test?
For steel sections typically used in buildings and bridges, for example, say a wide flange mild steel section, is there a comparison table available between hardness values (Rockwell, Vickers, Brinell etc) to YIELD and TENSILE strengths?
If so, it is sufficiently accurate to determine if the steel is say grade 36 ksi or grade 50 ksi without having to take a field sample and lab test?





RE: Indentation hardness correlation to yield and tensile strength of mild steel
In terms of reliability - there is error in the hardness test, then there is error in the conversion to UTS, and further error in estimating yield off that. Whether or not if it is sufficiently accurate depends I think on the criticality of your application. Personally I have used scratch tests to tell the difference between our Australian grade 250 and 350 steels for first passes in non-critical situations.
RE: Indentation hardness correlation to yield and tensile strength of mild steel
RE: Indentation hardness correlation to yield and tensile strength of mild steel
RE: Indentation hardness correlation to yield and tensile strength of mild steel
RE: Indentation hardness correlation to yield and tensile strength of mild steel
Saying that the hardness to UTS comparison works specifically for ferritic steels is an interesting distinction. Let me preface this by saying I'm not a metallurgist, but does that mean it doesn't work on steels with significant non-ferrite fractions? In that case, why is the comparison posted up to 40, 50, 60+ Rockwell C? I would think that steels of those harnesses would have very little ferrite involved?
Thanks
RE: Indentation hardness correlation to yield and tensile strength of mild steel
RE: Indentation hardness correlation to yield and tensile strength of mild steel
0.6 for annealed or hot wrought material
0.8 for cold worked material
0.8 for martensitic material < 35 HRC, < 1000 MPa tensile strength
0.9 for martensitic material > 35 HRC, > 1000 MPa tensile strength