Heat treating
Heat treatment is in accordance with DIN EN a method or compound of several procedures for the treatment of a workpiece, wherein the workpiece is subjected to changes in temperature or the temperature sequence in order to obtain certain material properties. Thereby encompassing means can change, e.g., of carbon or nitrogen content, bring about. An associated warm forming or heating method of the surface protection do not fall under the definition of heat treatment.
Method
Under the heat treatment process for the treatment of materials are by thermal, chemical and thermal, or mechanical- thermal action to be understood, with the aim to achieve optimal characteristics.
In the heat treatment, a fundamental distinction between methods which bring about a thoroughgoing structural transformation and procedures only cause a transformation on the surface of a workpiece. The former method include, for example, the annealing and curing, i.e., the thermal process. The latter method amongst the diffusion and coating processes or to the thermochemical processes (eg, carburizing, case hardening, nitriding, Boriding ).
Another way of classification can be done in production-oriented or procedure -oriented stress.
Production-Oriented Method
- Stress-
- Annealing
- Normalizing
- Coarse grain annealing
- Diffusion annealing
- Recrystallization
Stress -based method
Thermal heat treatment
- Remunerate
- Austempering
- Surface hardening, inter alia,
Thermochemical heat treatment
- Carburizing
- Carbonitriding
- Nitriding
- Nitrocarburizing, inter alia,
Especially materials such as metals and their alloys and plastics are heat treated for the targeted setting their properties. Heat treatments of ceramics are usually carried out only in the context of the manufacturing process ( during sintering ).
The material to be treated passes through different temperatures at different times ( temperature -time curve ) and then cooled at different rates depending on the material and process in different media (water, oil, salt, inert gas, air). The range extends here from the furnace cooling up to the rugged quenching to set certain properties ( strength, hardness, toughness, microstructure, etc.).
In addition, chemical effects, mechanical or other stresses act purposefully. The respective process is carried out in suitable heat treatment equipment.
There are a variety of materials are heat-treated especially for increasing the strength, for example, some aluminum and titanium alloys ( precipitation-hardening ), and the copper. This is in all cases prior to solution heat treatment followed by quenching and subsequent precipitation. All metallic materials can (if desired or necessary for further processing ) are annealed. Sometimes this is as an intermediate step during the cold forming even mandatory.
For the cost of a tool or component is the careful heat treatment of critical importance. Thus, a high-alloy tool steel, heat-treated if he was wrong, have poorer technological properties, as a low-alloy steel which has been heat treated properly. A high quality, properly heat-treated tool steel is, however, always have better properties for the particular application. In order to produce high quality products is necessary an efficient control of these energy-intensive processes. This includes the appropriate use of Steuer-/Regelungselementen, burner technology and a coordinated combination of different refractory products (such as fire bricks and high temperature wool).