The rack itself is mainly anodized aluminum with stainless steel fasteners (screws, bolts and nuts) and some brass bushings. There are also a few Delrin parts. Delrin is an engineering thermoplastic used in precision parts requiring high stiffness, low friction, and excellent dimensional stability.
The fasteners are torqued at the factory and because of the chemical properties of steel mated to aluminum, need no thread-lock solution.
It is a good idea to occasionally check the fasteners and other parts to make sure they are secure and tight. Any mechanical connection can vibrate and loosen, so make sure this doesn’t happen to your rack. This is normal wear and tear.