Heatfan,
Do Alloy/Metal companies use lot of internet? Where are these factories? Are they aware of internet?
If so you may be able to sell it for $300.
Actually, you need to appraise .biz based on its business model. .biz cannot be acquired purely for resale. That's enough grounds to have the name confiscated.
I'd develop this in a way that exposes your name to as many players in the alloy business as possible. Great business vanity name which would attract offers to purchase your online biz