Composite technology of horizontal and vertical pouring of middle diaphragm of wear-resistant casting

The middle clapboard is a kind of flat and vertical plate, which means that the mold is molded at the horizontal position, the cavity turnover is poured vertically during pouring, and the middle clapboard is inserted at the joint of two kinds of liquid metal. The figure is the schematic diagram of flat and vertical wound bimetallic composite wear-resistant casting. The process is characterized by the use of intermediate diaphragms. This material connection will be completed by the diaphragms heated in the casting process. A winding riser system is set on both sides of the intermediate diaphragms to form a double riser system. When designing the bypass injection system, the direct impact of liquid metal on the intermediate diaphragm should be avoided. The winding speed of the two metals is the process parameter that needs to be strictly controlled in the composite process. The metal liquid level on both sides of the diaphragm should rise slowly at an equal speed, and ensure that the two metal liquid levels maintain the same height at any moment, so as to reduce the liquid pressure difference on both sides of the diaphragm. The inclination of the diaphragm caused by the pressure difference will lead to the uneven thickness of the wear-resistant casting. In serious cases, it will make the high liquid level metal flow through the gap between the diaphragm and the mold cavity to the side with low liquid level, affecting the composition and microstructure uniformity of the wear-resistant casting. In addition, when the two liquid metals rise at the same time, the rising speed also has a great impact on the quality of the bonding layer. If the rising speed is too fast, the inclusions and gases at the junction of the diaphragm and the liquid metal are not easy to be discharged and remain at the junction, affecting the strength of the bonding layer.

The advantages of the horizontal and vertical winding process are as follows: first, the blocking effect of the intermediate diaphragm greatly reduces the punching and mixing probability between carbon steel and high chromium cast iron; Second, due to the use of the stepped pouring system, the temperature field distribution in the process is conducive to the formation of sequential solidification of wear-resistant castings, which makes the feeding effect of wear-resistant castings good and the shrinkage cavity and porosity are greatly reduced; In addition, the metal liquid level rises slowly, so that the bonding interface between the diaphragm and the two metals is not easy to appear non-metallic inclusions and entangled pores, and the structure of wear-resistant castings is more dense; Third, through the reasonable design of the shape of the middle diaphragm, the bonding area and bonding force can be increased, and the thickness of the wear-resistant casting of the casting can be uniform. The disadvantage of this process is that it is complex; Component segregation occurs during the solidification of liner materials, resulting in uneven wear-resistance casting of the working surface of liner.

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