i dunno, but I put together a bunch of tool boxes today but they're all chinese boxes, but better quality chinese boxes, clean, no sharps or shavings, all come with zerust mats and really nice casters.
I don't know the actual quality level but those were the good ones that didn't have any problems.
for some reason we switched to a different manufacturer for kobalt tool chests, something about craftsman being in lowe's now.
I've only ever used them on mild steel, they're great for that but some people have said they dull quickly, I've used quarter inch bit relentlessly and it hasnt dulled.