7-43

7.37 In this problem, we are asked for the length of time required for the average grain size of a brass

material to increase a specified amount using Figure 7.25.

(a) At 600C, the time necessary for the average grain diameter to grow to 0.03 is about 6 min; and the total time to grow to 0.3 mm is approximately 3000 min. Therefore, the time to grow from 0.03 to 0.3 mm is 3000

min - 6 min, or approximately 3000 min.

(b) At 700C the time required for this same grain size increase is approximately 80 min.

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