Muffle furnace is widely used in various university laboratories, research institutes, industrial and mining enterprise laboratories, for chemical analysis, physical determination, as well as the sintering and melting of metals and ceramics, small objects and other heating, drying and heat treatment. At present, although the application of muffle furnace is extensive, there is still a lack of relevant detection means to measure its accuracy and performance, and finding a suitable and effective method is of great help to the detection accuracy and performance of muffle furnace, which is widely used in various industries.

In the machining heat treatment industry, the annealing and normalizing temperature, quenching and tempering temperature of metal materials have a decisive influence on the structure, mechanical properties and processing properties of metal materials. Therefore, in the actual production, it is often necessary to measure the temperature of each position in the furnace in order to consider the location of the workpiece in the high-temperature furnace to meet the specified temperature and thermal insulation accuracy of the heat treatment process.

As a kind of heat treatment furnace, muffle furnace is widely used, for the effective heating zone measurement and judgment research, to find a set of effective methods to directly help it, for the detection accuracy of muffle furnace.

Whether the insulation layer of the muffle furnace wall is filled uniformly, whether the sealing is completed, these factors also directly affect the insulation accuracy of the effective heating zone, in the actual measurement, often encounter some high temperature furnace due to no regular maintenance of the heat treatment furnace insulation performance decline. In order to ensure that the insulation accuracy of the effective heating zone should meet the process requirements, then only the effective heating zone space can be reduced, although the insulation accuracy of the effective heating zone meets the process requirements, but the space of the effective heating zone is reduced, which directly affects the quality uniformity of the workpiece heat treatment. Therefore, the determination results of the effective heating zone of the muffle furnace come from two aspects, one is the intrinsic thermal insulation performance of the heat treatment furnace itself, and the other is whether the temperature control system is reasonable. If the accuracy of the temperature measurement instrument is very high, the temperature control method adopts PID intelligent continuous adjustment, and the internal quality of the furnace is poor, then the accuracy of the effective heating zone of the muffle furnace will not be high.