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4 years ago

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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?

1 answer:

polet [3.4K]4 years ago

4 0

Answer:

HV = 372.4 KGf/mm^2

$HR_C = 39.445$

Explanation:

given data:

minimum tensile strength = 1240 MPa

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

$\sigma_{vrs} = 3.4 \times H.B$

$H.B = \frac{1240}{3.4} = 364.7$

1) relation betwen H.B and Rockwell is

$HR_C = 6.96 + 0.089 HB$

$HR_C = 6.96 + (0.089\times 365} = 39.445$

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

$HB \times 1.05 = HV + 10.5$

$HV = HB\times 1.05 - 10.5$

HV = 372.4 KGf/mm^2

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2 years ago

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nirvana33 [79]

Answer:

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Explanation:

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Room Temperature $T_1$ = 20°C

outer diameter of the collar $D_o = 95 \ mm$

inner diameter of the collar $D_i = 60 \ mm$

pin diameter $D_p$ = $60.03 \ mm$

Clearance c = 0.06 mm

a)

The temperature to which the pin must be cooled for assembly can be calculated by using the formula:

$(D_i - c )-D_p = \alpha * D_p(T_2-T_1)$

$(60-0.06)-60.03=12.3*10^{-6}*60.03(T_{2}-20^{0}C)$

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$T_2 = -101.89^ \ ^0}C$

b)

To determine the radial pressure at room temperature after assembly ;we have:

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