Coppersmith extensive degree it must be annealed. This process involves heating the metal and then rapidly cooling it in water. The cooling stage is known as quenching. By heating the copper, the molecules in the metal are relaxed, and thus able to align themselves in a more uniform fashion. This allows for easier shaping of the metal. In order to keep this uniformity within the metal, it is cooled instantly. This prevents the molecules from moving around and causing tension in the structure of the metal. Unlike ferrous metals—which must be cooled slowly to anneal—copper can be cooled slowly in air
Wankel engine piston engine, in which the cylinder is heated by the combustion process and then cooled by the incoming charge, Wankel rotor housings are constantly heated on one side and cooled on the other, leading to high local temperatures and unequal thermal expansion. While this places great demands on the materials used, the simplicity of the Wankel makes it easier to use alternative materials, such as exotic alloys and ceramics. With water cooling in a radial or axial flow direction, and the hot water from the hot bow heating the cold bow, the thermal expansion remains tolerable. Top engine temperature has