Thermal characteristics of enamels and enamelled metal sheets

The main task of the research was to find out why sometimes cracking of the enamelled layer occur and to what extent enamel layer affects the heat transfer in the cooking oven. The samples of the enamelled streel sheet were metallographically analysed by scanning electron microscopy (SEM-EDX) and optical microscopy (OM). Measurements of the thermal properties of two types of enamels, which are used for oven interior enamelling was carried out in accordance with the standard ISO 22007-2 by transient planar heat source method (TPS Hot Disk 2200). To ensure proper measurement conditions, the samples of the enamels were prepared in the form of thick layers. The results show that enamel density has significant influence on its thermal properties. An assessment of the influence of the thermal conductivity of the enamel layer on the heat transfer in the oven is also given.