1. Structure of cast impeller
The stainless steel impeller shown in Figure 1 is a key component of a large pharmaceutical machinery in a pharmaceutical factory in Baoji. Figure 2 shows the main dimensions of the impeller. The outer diameter of the impeller is Φ 700mm, 130mm high, 202kg net weight of a single piece, the spoke part is a large plane, the blade spacing is small, layers are staggered, the shape is complex, streamlined, the wall thickness is only 5mm, the number is up to 54, and the working environment is in a highly corrosive medium.
2. Technical requirements
(1) The impeller is made of zg1cr18ni9ti and its composition shall meet the requirements of gb2100-80 casting standard;
(2) Casting defects such as slag inclusion, air hole, crack, shrinkage cavity and looseness are not allowed on the blade; Surface roughness RA3 2～1.6 μ m. Dimensional tolerance cT4 ~ CT5; The rim ovality is required to be high, which is 0 ~ 4mm, and the distance difference between adjacent blades shall not exceed 2mm;
(3) The defect diameter of rim, hub and spoke shall not exceed Ф 2mm；
(4) After heat treatment, it is non-magnetic and its mechanical properties meet the casting standards.