Ah ha! That may explain it then. Mine are definitely stainless steel and very heavy! I have had no evidence of cracking. I am thinking then that this issue that Killclimbz was telling me about may be the result of them switching to alluminum ones if they have but I don`t think any of the slider plates are made of aluminium; it`s too soft of a metal to hold up to the pins. I believe stainless steel is non magnetic so you cant rely on that. I would be surprised if they did switch to aluminium really. Check the weight, I am thinking you will agree that they are too heavy to be made of aluminium.
Mine are black anodized aluminium. Ill get a weight on them when I get a chance. I work with metal all day so I can tell its aluminium just by holding them in my hand, the weight, the grain structure on the folds and also by the fact that they are hard anodized
3xx series stainless is non magnetic so yeah if they are general grade stainless they wont stick