Unformatted text preview: Spheroidite not possible 0-1.0 %C Therefore, only fine pearlite has a composition range overlap for both of the hardness and ductility restrictions; the fine pearlite would necessarily have to have a carbon content between 0.45 and 0.48 wt% C. 10.D3 This problem inquires as to the possibility of producing a iron-carbon alloy having a minimum hardness of 175 HB and a minimum ductility of 52%RA. The composition and microstructure are to be specified; possible microstructures include fine and coarse pearlites and spheroidite. To solve this problem, we must consult Figures 10.22(a) and (b). The following is a tabulation of the composition ranges for fine and coarse pearlites and spheroidite which meet the stipulated criteria. Compositions for Compositions for Microstructure HB ≥ 175 %RA ≥ 52% Fine pearlite > 0.37 %C < 0.34 %C Coarse pearlite > 0.44 %C < 0.40 %C...
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- Tensile strength, 40%, fine pearlite coarse, pearlite Coarse pearlite, Microstructure Fine pearlite, coarse pearlites