Three axles snapped... Either you had a 'bad batch' (unlikely) or you either have terribly abusive operators or a floor that has moon craters. It's apparant from your post that you see a problem. From what you've written I see 3 causes (pretty much the same breakdown for any business):
1. The nature of the business and it's product causing damage - your molten splashes
2. The operator - normally the most costly group
3. The physical environment i.e. the floor, dock plates.

I suspect that there's little you can do with the first group, the third is costly and the second is unwilling to change 'the way we've always done it'. Welcome to our world.
If you evaluate your operation. Start with the easiest fix - probably the floor, and let the operators know what/why. They'll know a change is coming, and hopefully start to change their behaviour. Next, introduce a forklift operations plan, and give it teeth, discipline the worst drivers, the others will change.

I wish you luck