Question

What is the hardness (HB) of each of the alloys?

(a) 0.25 wt%C with spheroid:te,
(b) 0.25 wt%C with coarse pearlite,
(c) 0.60 wt%C with fine pearlite, and
(d) 0.60 wt%C with coarse pearlite.

Answer 1

The hardness (HB) of each alloy is different based on their composition and microstructure. The values for the given alloys are: (a) 0.25 wt%C with spheroidite: HB = 8.81, (b) 0.25 wt%C with coarse pearlite: HB = 8.63, (c) 0.60 wt%C with fine pearlite: HB = 6.23, and (d) 0.60 wt%C with coarse pearlite: HB = 8.92.

Step-by-step explanation:

The hardness (HB) of each of the alloys can be determined by looking at their composition and microstructure. Alloy hardness is influenced by factors such as carbon content, cooling rate, and the resulting microstructure. Here are the hardness values for the given alloys:

(a) 0.25 wt%C with spheroid: HB = 8.81

(b) 0.25 wt%C with coarse pearlite: HB = 8.63

(c) 0.60 wt%C with fine pearlite: HB = 6.23

(d) 0.60 wt%C with coarse pearlite: HB = 8.92

These values represent the relative hardness of the alloys, with higher values indicating greater hardness.

Answer 2

A) 62.5 HB

B) 75 HB

C) 95 HB

D) 90 HB

Step-by-step explanation:

From the attached animated figure, we can trace the values of hardness (HB) for each of the alloys.

The scale we are using in the attachment to read our values for HB is the HRB scale that shows the Rockwell hardness on the right hand side.

A) For 0.25 wt%C with spheroidite, Tracing the line out on the green curve and reading the scale on the right, the hardness is approximately 62.5 HB

B) For 0.25 wt%C with coarse pearlite, Tracing the line out on the blue curve and reading the scale on the right hand side, the hardness is approximately 75 HB

C) For 0.60 wt%C with fine pearlite, Tracing the line out on the red curve and reading the scale on the right hand side, the hardness is approximately 95 HB

D) For 0.60 wt%C with coarse pearlite. Tracing the line out on the blue curve and reading the scale on the right hand side, the hardness is approximately 90 HB