Due to the particularity of the shape of the large girth gear, the small R area of the non-machined surface has a thin wall. If the pouring process is not appropriate, casting defects such as loose metal structure, slag inclusion, pores, coarse grains, and surface cracks are generally prone to occur in the pouring process. As a result, ultrasonic and magnetic particle inspections do not meet the requirements of relevant national regulations.

Therefore, in the casting process, the composite requirements of the pouring process are strictly required, and the molten steel produced by the refining ladle is used as much as possible and poured with full risers. At present, some large state-owned enterprises in China adopt non-full riser pouring due to consideration of cost; generally, the number of risers of large girth gear is equal to the number of reinforcing rib plates, and 8 to 12 risers are adopted. In this way, the cost of the blank is controlled, but the quality of the blank is reduced, and the quality problem of the casting blank is basically solved by the method of welding repair. However, such a blank quality is difficult to pass magnetic particle inspection after finishing.

In addition, before pouring, computer simulation software is used to simulate the pouring plan, so as to modify the pouring model in time, and to better control the quality of the blank.

The above are the problems and countermeasures in the casting process of the girth gear introduced by CHAENG for you. If you still have questions, you can consult us online, or visit our website for more information.