14.14.2 Billet Heating Costs The costs for heating the billet or bar end to the appropriate forging temperature can be estimated by determining the energy costs for heating. These can be obtained by multiply- ing the billet weight by the material specific heat and the required temperature rise. For mall forgings, this cost is relatively small, but for large forgings that may require several reheats between operations the heating costs may become significant. PROBLEMS The sample forgings (A, B, and C) shown in Figures 14.30 through 14.32 are used for the following problems. Material Material cost ($/kg) Material density, p (g/cm) Length, L (mm) Width, W (mm) Thickness, T (mm) Part volume, V (cm) Part Data Medium carbon steel 1.00 7.83 254 51 23 43 48 594 30 GURE 14.30 mple forging A. Projected area, A, (cm) Outer perimeter, P, (mm) Number of surface patches