According to the element distribution of line scanning and surface scanning, the thickness of interface bonding zone of composite samples with different interval of 75s (2#), 90s (1#) is inferred (as shown in Figure 1). 2. The thickness of the interface bonding zone of the sample is about 43 μ m. The temperature difference of the sample is large. The high chromium cast iron makes the low alloy steel rise rapidly and brings a lot of energy to promote the long-time and long-distance diffusion of elements. Therefore, the thickness of 2#.
In order to more accurately measure the interface adhesion of bimetallic materials, impact loads parallel to the composite interface were applied on the carbon steel side, 0mm, 8mm and 16mm away from the composite interface for composite samples with an interval of 75s (2#) and 90s (1#) respectively. The test schematic diagram 2A. The test results are shown in Fig. 2b. The impact toughness on the interface is the lowest. The farther the impact load is applied from the interface, the higher the impact toughness. The impact toughness of the sample with an interval of 75s (2#) is high due to its thick composite thickness.
In conclusion, the time interval of composite pouring is the most critical process parameter to determine the interface quality of high chromium cast iron and carbon steel composites. When the time interval of composite pouring is too short, the high chromium cast iron injected first does not fully fall below the solid phase line, and the solid and liquid phases coexist. At this time, the injection of high-temperature carbon steel liquid will form the opposition between the liquid phase of carbon steel and the liquid phase of high chromium cast iron, and finally form the coagulation structure phase of steel and iron, resulting in that the prepared composite material can not meet the required mechanical and service properties; When the interval of compound pouring is too long, the solid surface temperature of the high chromium cast iron injected first will drop too low, and the solid cast iron actually acts as a strong cold iron on the heat transfer boundary. At this time, the injection of carbon steel liquid can only make the high chromium cast iron surface enter the melting state locally, and it is difficult to form a full and high-quality metallurgical bonding at the composite interface; The appropriate time interval for composite pouring should be between the range of coagulation and liquid-solid mechanical combination. According to the test results of microstructure, composite interface thickness and impact toughness, the most appropriate time interval for composite pouring is about 75s, and it can be inferred that in the appropriate pouring time interval, the interface thickness decreases with the increase of pouring interval, High quality metallurgical bonding can be seen between the two metal materials.