by Jacob Morgan » 10 Feb 2016 10:27
Aluminum bodied padlocks are probably machined from extrusions. Extrusions are made from billets. Billets are made by the DC casting process, usually at aluminum smelters. Crucibles of aluminum are brought over, put in a furnace, possibly with some scrap, and then sampled with a spectrometer to check for the elements. Then, if needed, "hardeners", elements like manganese, iron, silicon, etc., are added to bring it in spec. Very commonly in the trough that takes the molten metal to the billet molds there is a wire feeder that feeds a certain number of inches per minute of a coil of titanium-boron wire into the molten aluminum where it quickly melts and mixes in, again, it is added as a grain refiner, not to impart strength directly as a result of the titanium itself. So very likely every extruded aluminum padlock out there has some titanium in it, just like your car's radiator or the disposable pie pans in the grocery store or beer cans contain titanium. So it could be pure marketing to talk up something that was already there.
Or, it could have something to do with a coating on the padlock. Contrary to popular belief, aluminum is notorious for corrosion. Usually it reacts very readily and (hopefully) forms a protective skin that is not visible. But, exposed to weather and humidity it can "water stain" and form a bad looking white powdery appearance. And exposed to humidity and touching other metals, especially zinc (e.g., anything galvanized) it can form nasty black discoloration. The remedy to that corrosion is to clean it with phosphoric acid. So it could have to do with some sort of coating to protect from corrosion. Some types of titanium coatings also help with abrasion resistance, which never hurts with locks.
