The material of the guide rail steel castings is ZG32MnMo. Using the company’s current 3T alkaline arc furnace smelting and 5 t bottom pouring ladle, a process trial production of 4 boxes/4 guide rail steel castings was conducted on the resin sand flexible molding production line according to the initial casting process plan. After inspection and testing of the process trial produced guide rail steel castings through line marking, dissection, and trial processing, it was confirmed that the following casting defects exist in the guide rail steel castings:
(1) There are insufficient pouring and cold shut defects in the middle and edge of the upper plane of the guide rail steel casting;
(2) After dissection of the guide rail steel casting, it was found that there were shrinkage defects at the side plates on both sides and at both ends of the intermediate guide rail surface, while no shrinkage holes or porosity defects were found at other parts, as shown in Figure 1;
(3) There are thermal cracks at the corners of individual connecting ribs of guide rail steel castings;
(4) The inner cavity dimensions of the guide rail steel castings in the length direction are all too large, and the dimensions are out of tolerance;
(5) The guide rail steel castings have deformation, and the four trial produced guide rail steel castings have upward warpage at all four corners of the guide rail surface, as shown in Figure 2.
