Study on Necessity of Property Restoration Heat Treatment for Hot-pressed Formed Q345R（R-HIC） Head

The heat treatment specimens of simulated head thermal forming were prepared, the necessity of the property restoration heat treatment for the hot-pressed formed head made of Q345R（R-HIC） normalized steel plate, as well as the influence of the property restoration heat treatment on the mechanical properties of the hot-formed head of Q345R（R-HIC）normalized steel plate were studied. Through comparative analysis of key indicators such as the microstructure, tensile properties, bending properties and impact toughness of the steel plate before and after the property restoration heat treatment,the action mechanism of the property restoration heat treatment on the mechanical properties of Q345R（R-HIC） normalized steel plate was comprehensively analyzed. The results show that the property restoration heat treatment for the hot-pressed formed head of Q345R（R-HIC） normalized steel plate is not necessary. In practice, it is required to reasonably implement this treatment according to the requirements of the design drawings of pressure vessels to improve the mechanical properties of the head, make it fully comply with the requirements of special equipment related standards such as Pressure Vessel Head（GB/T25198—2023）, which can provide a theoretical basis and technical guidance for the optimization of the manufacturing process of Q345R（R-HIC） steel pressure vessel heads.