In this paper, ultrahigh‐strength steel AF1410 was milled with the carbide tool, and a total of thirty experiments were performed based on central composite design (CCD) of response surface methodology. The prediction models of milling force and surface roughness are established, respectively. The influence of milling parameters (milling speed, each tooth feed, radial depth of cut, and axial depth of cut) on milling force and surface roughness is studied by ANOVA and established prediction model. Multiobjective optimization of milling parameters is accomplished based on nondominated sorting genetic algorithm II (NSGA‐II) with milling force, surface roughness, and material removal rate as optimization objectives. The surface roughness, cutting force, and material removal rate are important indexes to measure the energy consumed in the process of product, the surface machining quality, and machining efficiency of processing, respectively. In order to minimize milling force and surface roughness and maximize material removal rate, NSGA‐II was used for multiobjective optimization to obtain the optimal fitness value of the objective function. The NSGA‐II has been applied to obtain a set of optimal combination of parameters from the Pareto‐optimal solution set to enhance the machining conditions.

AF1410 is a low carbon high alloy ultra-high strength steel. It not only has high strength and high toughness, but also has a high stress corrosion resistance. However, due to the characteristics of hard quality and poor thermal conductivity, AF1410 is a difficult material to process. In the process of milling, the geometric factors of process parameters, the flexible deformation of milling cutter and the flutter of the process system all affect the surface roughness, which makes it difficult to predict the surface roughness of milling parts. In order to solve this problem, a prediction model for surface topography of ultrahigh strength steel AF1410 was studied. To solve this problem, this paper studies the formation of milling surface topography, considers the dynamic displacement of the milling system, proposes a modeling method of surface topography based on the dynamic characteristics of the milling system and forms a prediction model. On this basis, the surface topography of ultra-high strength steel is simulated and analyzed, and the accuracy of the model is verified by experiments. The study realizes the prediction of milling surface topography of AF1410 parts and reveals the formation mechanism of milling surface topography from geometric and physical perspectives.

The machining mechanism and process parameters of ultra-high strength steel 16Co14Ni10Cr2Mo are still lack of complete understanding. By changing the milling condition, the influence of process parameters on cutting force, such as Radial milling depth, Axial milling depth, Feed per tooth and milling speed, is studied,and in the meanwhile that the surface morphology and hardness of 16Co14Ni10Cr2Mo after machining are analyzed. Indicating that the milling force increases with the increase of axial milling depth, feed rate and radial milling depth. With the increase of milling speed, the milling force reduces. The effect of axial cutting depth and radial cutting depth on cutting force is maximum. For 16Co14Ni10Cr2Mo ultra-high strength steel, it is suitable to use small cutting depth and high milling speed. On the surface of milling material, partial melting and partial oxidation of chips occur. When the milling speed and feed rate increased, the surface hardness of the material did not change significantly, and there was no work hardening.