Preplaced (precast) inserts are components that are installed (buried) in concealed works in advance. They are the components placed during the structural pouring process and are used for lap joints during the construction of the upper structure. This facilitates the installation and fixation of external engineering equipment foundations. Preplaced inserts are usually made of metal, such as steel and iron.Or cast ironAlso available in woodPlastic and other non-metallic rigid materials.