Originally Posted by
Airburst
An alloy is basically a mixture of two or more metals. In the bike industry, "alloy" tends to be used to describe parts made from an alloy that consists mainly of aluminium (i.e. "aluminium alloys"), despite the fact that a lot of steel bike parts are made from alloy steels, and quite a lot of titanium parts are made from titanium alloys.
Right, for steel alloys the say "cromo" or just use the branding (Reynolds 853 or whatever) but for alu sometimes they'll use the specific alloy (6061, 7075, etc) but more often they say alloy (ally nipples, alloy steerer, alloy seatpost) mostly to generally distinguish from either brass (nipples) or carbon. Never (or at least rarely) is a bike component made from a steel alloy referred to generically as alloy.