Question

A company specification calls for a steel component to have a minimum tensile strength of 1240 MPa. Tension tests are conducted on selected samples, but all components are also subjected to Vickers hardness testing. (A) What HV (in Kgf/mm2) is the minimum acceptable value? (B) If hardness is measured using Rockwell C hardness test, what is the minimum HRC value that is acceptable?

Answer 1

HV = 372.4 KGf/mm^2

`HR_C = 39.445`

Step-by-step explanation:

given data:

minimum tensile strength = 1240 MPa

we knwo that
`\sigma_(vrs)` and brinell hardness number (HB} relation given as

`\sigma_(vrs) = 3.4 * H.B`

`H.B = (1240)/(3.4) = 364.7`

1) relation betwen H.B and Rockwell is

`HR_C = 6.96 + 0.089 HB`

`HR_C = 6.96 + (0.089* 365} = 39.445`

2) relation between HB and Vickers hardnes HV is given as

`HB * 1.05 = HV + 10.5`

`HV = HB* 1.05 - 10.5`

HV = 372.4 KGf/mm^2