In order to improve the use performance of metal materials, we can carry out heat treatment and processing. Heating is only one of the processes in the heat treatment process, but how to not get reasonable heating in the heating process will lead to a number of defects, and even lead to the failure of normal use of metal materials. In order to be able to carry out the safety heat treatment process for metal materials, Qingdao Fengfeng East heat treatment shares common defects in the heating of metal heat treatment.
Protection of metal during heating of metal heat treatment
When the metal is heated, the workpiece is exposed to the air, which often occurs oxidation and decarburization (that is, the carbon content on the surface of steel parts is reduced), which has a very adverse effect on the surface performance of parts after heat treatment.
Therefore, the metal should be heated in controllable or protective atmosphere, molten salt and vacuum, and can also be protected by coating or packaging. Heating temperature is one of the important process parameters of heat treatment process. The selection and control of heating temperature is the main problem to ensure the quality of heat treatment. The heating temperature varies with the metal material being treated and the purpose of heat treatment, but it is generally heated above the phase change temperature to obtain high temperature structure.
In addition, the transformation needs a certain time, so when the surface of the metal workpiece reaches the required heating temperature, it must be kept at this temperature for a certain time, so that the internal and external temperatures are the same, and the microstructure is completely transformed, which is called the holding time. When high energy density heating and surface heat treatment are used, the heating speed is extremely fast, and there is generally no heat preservation time, while the heat preservation time of chemical heat treatment is often longer.
On 2018-08-08 11:45:46
