Forge bucket teeth is tougher, and has longer wear life, but cast bucket teeth has good properties and cheaper.
Forge bucket teeth are made from heat treated alloy steel to help sustain wear resistance, so you can often come to expect a longer wear life from forge bucket teeth. The downsides are that there are more limits on shaping and forged bucket teeth come at a higher cost.
Cast iron bucket teeth are made from austempered ductile iron and heat treated to offer maximum resistance to wear and impact. They are strong and lightweight in design and cast iron bucket teeth are self-sharpening. They can last almost as long as forged bucket teeth and they are significantly cheaper – making them more economical and cost effective.
When deciding which option is best, you need to understand the material being processed, abrasion level and impact the machine is subjecting the tooth to.
So the largest difference is actually in impact – cast does not react well to high torsional forces breaking as it is a more brittle compound.
Whereas the forged tooth has long grains of steel giving it much greater torsional flexibility – so it will almost bend before it will break. Every solution is different so it's important you understand what's required.
Cast iron bucket teeth