## 1 Introduction  
Metal spinning, as an advanced processing technology, is widely applied in the field of metal plastic forming. It has advantages such as no cutting or less cutting in the stretching process [1]. The spinning forming of thin-walled revolving parts has the advantages of high manufacturing accuracy, low energy consumption and low processing cost. Especially during the forming process, the metal flows along the tangential direction of the forming parts, the internal grain of the metal is not distorted, and the residual stress is small, which makes the spinning process better than other forming methods [2; 3; 4; 5]. Thin-walled parts, a complex rotating part with thin wall thickness and large diameter, are widely used as external loading parts of aero-engine casings. They usually work under long-term high temperature, high pressure and alternating loading. The material is usually superalloy, which is difficult to form and control. After forming, there are varying degrees of residual stress in the interior, which has become a potential danger for aero-engine service. How to improve the spinning forming quality of thin-walled conical parts with variable-section has become a research hotspot in China and abroad. In order to improve the spinning quality of thin-walled conical parts with variable-section and to improve their service life, many scholars at home and abroad have studied different aspects of the spinning process. [PERSON] et al. [6] formed a magnesium alloy conical part with a ring reinforcement by wedge extrusion and analyzed the variation law of equivalent strain. [PERSON] et al. [7] studied the effects of the material self-plasticity on the spinning forming quality with LF2, LF6 and LF21 aluminum alloy as the research objects. [PERSON] et al. [8] and [PERSON] et al. [9] established a model of spinning for processing double conical parts and analyzed the influence of the forming parameters on stress-strain, which provides ideas for spinning the conical parts more efficiently. [PERSON] et al. [10] and [PERSON] et al. [11] used the method of combining the experiment of spinning cylindrical parts and finite element simulation to analyze the effect of process parameters on the surface residual stress in spinning cylindrical parts. They found that residual stress fluctuated with the change of process parameters. [PERSON] [12] and [PERSON] et al. [13] studied the spinning forming of a connecting rod bushing and head, and analyzed the mechanism of residual stress. They respectively used the X-ray method in nondestructive testing and the residual stress release of small holes in destructive testing to measure the surface residual stress of the workpiece. [PERSON] et al. [14] and [PERSON] et al. [15] proved by hot power spinning high-strength steel that hot spinning could reduce the residual stress of the parts. [PERSON] et al. [16] analyzed the influence of process parameters on wall thickness deviation, ellipticity, straightness and roughness in the flow spinning of IJ50 soft magnetic alloy. He [17] studied the distribution and variation law of equivalent stress-strain in the power spinning process of a TA15 titanium alloy cylindrical tube and the main structural parameters on equivalent stress-strain. [PERSON] et al. [18] analyzed the influence of process parameters on the forming quality during the first pass and second pass spinning forming of thin-walled conical parts. They proposed to choose a larger gap deviation rate of the roller to avoid wrinkling and cracking. Based on the above-mentioned research, it can be seen that the existing study mainly focuses on the plastic state, stress, residual stress and so on. There is no systematic research on the influence of process parameters on the forming loading of thin-walled conical parts with variable-section. In this paper, the superalloy GH1140 thin-walled conical casing with variable-section is taken as the research object to study the influence of forming process parameters on the forming load.