A crucially new casting process and equipment employed to realize it provide for obtaining coreless hollow-bore cylinder work pieces exhibiting the output rate of 100-240 castings/h. The technology ensures improved mechanical and performance properties of casting material.
Fig. 1 – The process plant for cycle-continuous casting.
Fig. 2 - cycle-continuous dip-forming process: 1 - metal duct; 2 - connection nozzle; 3 - fixed molding unit; 4 - movable molding unit; 5 - casting
The developed method is based on the principle of ensuring proper conditions for directional solidification. Its essence is as shown on Figure 1, 2. Liquid metal is fed through a bottom gate and a connection nozzle into a water-cooled mold consisting of a fixed and a movable section. Feeding continues till the appropriate casting height is reached. Then metal feeding is suspended to provide for molding a work piece wall of appropriate thickness. After skin making up the casting body solidifies it is drawn up from the fixed mold and metal bath with the help of gripping tools. Simultaneously, a new portion of liquid metal equal to the volume of the previous casting is fed into the mold. The cycle is reproduced. Thus, the casting process is effected in a cycle-continuous mode. The molding procedure is accompanied by intensive radial heat removal and abundant feeding of the solidification front with liquid phase over the entire solidification period. This eliminates shrinkage and gas porosity, presence of non-metallic and cinder inclusions in the casting body and ensures a high-dispersion structure, improved density and hardness of work-pieces. Absence of any core provides for free shrink-off both during casting solidification period and its subsequent cooling following extraction from the molding form, which helps to avoid pull cracks and microfissures. The technology allows due control of the cooling process to obtain required structure.

The developed technology helps save resources and energy since heat treatment employs only primary casting heat without any external power sources. Besides, it provides for a more effective use of waste materials resulting from casting process and mechanical treatment.
The technology ensures crucially new conditions for hollow-bore work pieces molding which presupposes directional solidification accompanied by intensive one-side radial heat removal and constant overheating of the metal bath at the solidification front.