Steel for thermal insulation and decoration is commonly employed in the construction market and performs a crucial function in industrial production and research. However, different heat treatment processes will directly affect the internal structure and performance of the thermal insulation steel. The existing thermal insulation and decorative steel cannot take into account the various mechanical properties of the steel. To get the optimal heat treatment method for the thermal insulation and decorative steel, the study carries out heat treatment of normalizing + tempering and quenching + tempering, and at the same time, constantly change the temperature to explore the structural structure and performance changes of the insulation steel in various thermal treatment procedures. The experimental results show that compared with other heat treatment processes, when quenching temperature is 910 °C, the tensile strength of the steel is 266 Mpa higher, the yield strength is 332 Mpa higher, the section shrinkage is 19% higher, and the hardness is 9.8 higher. The Akv impact energy at 70 °C is only 4.3 J lower, and the elongation is 22% lower. Therefore, among several different heat treatment processes proposed in the study, the quenching + tempering method is superior to the normalizing + tempering heat treatment process, and the quenching temperature is set at 910 °C, and the obtained thermal insulation steel has the best performance, which better meet the actual demand for this steel in the market and can serve as a guide for optimizing the heat treatment method of thermal insulation steel.

Keywords: Steel for thermal insulation and decoration, Heat treatment process, Microstructure, Mechanical properties.