Decrease a metal alloys ductility and increase it's hardness. A common method is to heat the material to well above it's recrystallization temperature and then quench it in a fluid such as oil, water or salt water.
In tool steels, cryogenic treatment can increase a materials strength and hardness as well as it's toughness and wear resistance. In electrical cables and electronics components cryogenics can improve conductivity and reduce micro-diode-effect noise.
Increase a metal alloys hardness but only on the outer surface. The material is heated in a furnace that is injected with an atmospheric gas rich in carbon. The outer surface of the material absorbs carbon from the atmospheric gas thus hardening the surface.
Gas & Pack Carburizing are similar but with Pack Carburizing, instead of injecting an atmospheric gas into the furnace the metal parts are packed in a metal box with each part surrounded by small pellets of carbon rich material. When the box is heated to the proper temperature the metal parts absorb carbon from the pellets which hardens their outer surface.
Heating ferrous alloys to approximately 100° F above the critical temperature range, followed by cooling in air. It is used to undo previous heat treating results so as to achieve a uniform grain structure.
Heating an alloy to a suitable temperature, holding long enough to reduce residual stresses, and then cooling slowly enough to minimize the development of new residual stresses. This treatment is used to relieve stresses caused by welding, cold working, machining, casting, and quenching.
Used to increase the toughness of iron based steels. Tempering is usually performed after hardening to reduce some of the excess hardness. It is accomplished by heating the metal to some temperature below the critical point for a certain period of time, then allowing it to cool in still air.
A vacuum furnace uses low atmospheric pressures instead of a protective gas atmosphere like most heat-treating furnaces. Metals treated in a Vacuum furnace experience less deformation and are much cleaner.
Sandblasting is when A mixture of high pressure air and sand is sprayed over parts to clean them
A machine hurls tiny ball bearings at parts to clean and polish them.
A preliminary heat treatment used to prepare a material for a desired reaction to a subsequent heat treatment.
Increase a metals ductility and reduce its hardness, making it more workable. For most ferrous metals annealing invloves heating a material to above its recrystallization temperature for a suitable amount of time and then cooling, in most cases slowly, in air.