In order to ensure that the experiment has accurate guidance for the inlet cylinder casting, the stepped shaped test block with the same main wall thickness as the inlet cylinder is selected. The section wall thickness of the step is 400 mm, 150 mm and 70 mm, and the length of each section is 220 mm. It is shown in Fig. 1.
According to the theoretical analysis and the practical experience of our company in other high-endcastings research, the carbon equivalent CE in the melting process and the amount of scrap charge as the main variable factors were set as the control group. For CE setting, the reasonable matching of C and Si contents is mainly considered, and the control group with different C and Si contents is set for grouping study. The addition amount of scrap charge is a process measure matching with the content of C element. The control group is set to study the influence trend of shrinkage cavity and porosity, and the reasonable addition proportion is finally selected. The composition of the casting test block is set as the target component of the final product after the molten iron is spheroidized and inoculated.
The control group was poured and analyzed. The shrinkage cavity and porosity tendency of casting and the morphology of thick and large section graphite were analyzed and studied in the detection and test link. The shrinkage cavity and porosity tendency was mainly studied by UT detection and physical and chemical anatomy, and the graphite morphology was mainly studied by metallographic examination and physical and chemical property testing.