After the production line of type 16 knuckle product is arranged and runs well, the trial production of the product will be started in February 2020. Firstly, the sample will be poured according to the original sand casting process. The main problems are as follows: due to the small drop height of feeding liquid level in the riser, the feeding effect of the riser is general, resulting in a large waste of liquid steel; There are obvious erosion and slag inclusion defects around the pin holes of more than half of the hook tongue products, and the sand sticking is also serious, which makes it difficult to clean up; Through magnetic particle flaw detection, micro cracks appear from time to time at the gate root, the middle and upper part of the inner wrist surface of the hook tongue, the opening of the hook tongue and the corner of the guard pin flange.
As shown in the figure, the situation of slag and sand inclusion around the pin hole of the product produced by the original sand casting process of the hook tongue and the need for welding repair after flaw detection are shown respectively. Due to the large changes in the optimized sand casting process, the mold must be purchased and processed again, and the cycle is long. Therefore, as of the writing of the paper, the trial product of the optimized sand casting process has not been formed. As a cooperative unit, Huazhong University of science and technology has put forward a series of transition schemes for improving the sand casting process of the hook tongue based on the original sand casting process of the hook tongue, which has achieved good results.