c. 此鑄砂是屬於多少峯砂？: ________ (請扼要說明理由) (篩網中有四個超過 10%，所以為四峯砂，其砂模性質較佳)

c. 計算過程： (注意：配料總重量為四種配料重量之和) | C₁=50x3.3/100+50x0.2/100+1x99/100 =1.65+0.10+0.99 =2.74 Si₁=50x2.2/100+50x0.2/100+1x75/100 =1.10+0.10+0.75 =1.95 Mn₁=50x0.6/100+50x0.6/100 =0.60 C₂=2.74(1+0.15)=3.151 Si₂=1.95(1-0.10)=1.755 Mn₂=0.60(1-0.15)=0.510 C=3.151x100/102=3.089=____1____% Si=1.755x100/102=1.721=____2____% Mn=0.510x100/102=0.500=____3____% CE=3.089+1/3(1.721)=3.663=____4____% 1.