Can non-ferrous metals/alloys (copper, brass, bronze) be tempered (made harder) by temperature control alone, like ferrous metals? I understand it's simple to anneal copper, brass, etc., just by making them hot enough.
I'm Wondering if it's possible to temper non-ferrous metals without having to either work-harden it or media-blast it (essentially work hardening).
Most non-ferrous alloys are heated in order to form a solution.
Annealing:
Most non-ferrous alloys that are heat-treatable are also annealed to relieve the hardness of cold working. These may be slowly cooled to allow full precipitation of the constituents and produce a refined microstructure.
Different annealing techniques are subjected with non-ferrous alloys like recrystallization annealing, partial annealing, full annealing, and final annealing.
Quenching
Quenching is a process of cooling a metal at a rapid rate. This is most often done to produce a martensite transformation. In ferrous alloys, this will often produce a harder metal, while non-ferrous alloys will usually become softer than normal.
Reference: Wikipedia
> character) quotes that are pulled directly from the text.
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You have a misconception that tempering is hardening. It is softening done after hardening to relieve stresses, improve ductility and toughness .
From this source
In nonferrous alloys, eutectoid transformations, which play such a prominent role in steels, are seldom encountered.
On the other hand, the principles associated with chemical homogenization of cast structures are applicable to many alloys in both classes. Examination of the heat treatment used for nonferrous alloys reveals that a wide variety of processes are employed. . Annealing after cold working is a very important heat treatment for nonferrous alloys.
Basically if the non-ferrous alloy has a eutectoid region in its phase diagram , tempering can be used after hardening. But non-ferrous usually are not hardened in this way. Age hardening, Precipitation hardening, Dispersion strengthening are commonly seen in non-ferrous alloys.
No.
Neither ferrous, nor non-ferrous metals can be hardened by tempering.
Tempering generally refers to steel and it does the opposite of hardening. It reduces the hardness and brittleness of the steel (softens it) while improving the toughness and making it more ductile. This makes the steel better able to handle further cold processing and makes it more impact resistant (which is why e.g. swords need tempering - otherwise they are too hard and brittle to withstand impact).
Annealing is used on non-ferrous metals, generally for similar reasons (although also used to improve conductivity in some cases).
No.
Neither ferrous, nor non-ferrous metals can be hardened by tempering.
Tempering generally refers to steel and it does the opposite of hardening. It reduces the hardness and brittleness of the steel (softens it) while improving the toughness and making it more ductile. This makes the steel better able to handle further cold processing and makes it more impact resistant (which is why e.g. swords need tempering - otherwise they are too hard and brittle to withstand impact).
Annealing is used on non-ferrous metals, generally for similar reasons (although also used to improve conductivity in some cases).
Qualifier: not too sure of this, but I have a vague recollection that some of the popular "american" (as opposed to english) dictionaries actually do define tempering as hardening metal ...
