Alternatives (i) Malleable Cast Iron Grey Cast Iron 3.5% Ni, 0.4% Carbon Al Alloy 2024-T4 Al Alloy 6061-T6 Sigma Yield (ksi) 54 30 200 60 E (10^6 psi) 25 13 30 10.6 Corrosive Resistance 1 1 2 3 (Btu/lbm*F*min) 50 50 50 200 38 10 3 200 Table 1: Data for Robotic Arm Decision in Ammonia Plant cost ($/ft) Key: Corrosive Resistance 1->4 22 20 20 27 25 least -> greatest