Puncher Tip Alloys for Aluminum Reduction Cells

Summary

Ore puncher tips operate in an extremely harsh environment in point-fed aluminum reduction cells and suffer rapid weight loss through corrosion attack when made from hot-rolled carbon steel bar. This study was undertaken to identify more durable materials for puncher tip fabrication.

Sample coupons representing nine candidate puncher tip alloys were welded to special ore puncher tips operated in a point-fed prebake cell. Rate of thinning was determined for each coupon, and effective tip life and cost per tip-day of operation were calculated. Hastelloy X was the most durable material and indicated lowest overall expense despite high initial cost. Cast stainless steels were quite durable; the most highly alloyed performed best. Cast and wrought carbon steels performed poorly.