Processing of axle box for high speed freight car bogie

The axle box of our company's high-speed truck bogie (see Figure 1) is a key component of the bogie. The machining accuracy of the inner hole directly affects the performance of the bogie and its safe operation. The material is TB/T 2942-B grade, the inner hole is (?) 230mm, the surface roughness is R_a3.2μm, and the thinnest wall thickness is only 25mm. The initial trial production is quite difficult.