为揭示铸&锻高温合金GH4198锯齿形切屑的成形机理，并通过理论模型预测切屑形貌，开展了直角切削实验，再基于滑移线场模型预测切屑的几何形状，分析切削参数对切屑成形的影响。提出了考虑刀具钝圆半径的三阶段锯齿形切屑成形模型，建立了二维正交切削的热力耦合有限元模型，并通过实验验证有限元模型的合理性。基于仿真得到的切屑形成过程的应力、等效塑性应变和温度等参数的变化，分析了锯齿形切屑的成形机理。结果表明：剪切角随切削速度和进给量的增加而增大，切屑厚度随切削速度的增大而减小；切削速度为10、20和30 m/min时，切屑厚度预测值的相对误差分别为4.20%、12.34%和24.73%，最大切屑厚度压缩比分别为3.19、2.78和2.26，切屑锯齿化程度分别为0.20、0.36和0.58；切削速度为30 m/min时，切屑出现明显裂纹，且锯齿齿形整体倾斜；刀具进给量为0.05、0.10和0.15 mm/r时，最小切屑厚度预测值的相对误差分别为17.66%、8.66%和5.07%，最大切屑厚度压缩比分别为2.82、2.78和2.61，切屑锯齿化程度分别为0.12、0.36和0.42；滑移线场模型能有效预测切屑厚度随切削参数的变化；随切削速度和进给量的增大，切屑厚度压缩比呈减小趋势，锯齿化程度增大且增大趋势逐渐减缓。该文还通过有限元仿真分析了刀具钝圆半径对切屑成形的影响，验证了锯齿形切屑成形理论模型的有效性。

In order to reveal the formation mechanism of saw tooth-shaped chips in cast & wrought high-temperature alloy GH4198 and predict chip morphology through theoretical models, orthogonal cutting experiments were conducted. Based on the slip line field model, the geometric shape of the chips was predicted, and the influence of cutting parameters on chip formation was analyzed. A three-stage formation model of saw tooth-shaped chips considering the tool edge radius was proposed, and a two-dimension orthogonal cutting thermo-mechanical coupled finite element model was established, with its rationality being verified through experiments. By analyzing the variations of stress, equivalent plastic strain and temperature during the chip formation obtained from simulations, the formation mechanism of saw tooth-shaped chips was investigated. The results show that the shear angle increases with the increase in cutting speed and feed rate, while the chip thickness decreases with the increase in cutting speed. At the cutting speeds of 10, 20 and 30 m/min, the relative errors of the predicted chip thickness are respectively 4.20%, 12.34% and 24.73%, the maximum chip thickness compression ratios are respectively 3.19, 2.78 and 2.26, and the chip serration degrees are respectively 0.20, 0.36 and 0.58. At a cutting speed of 30 m/min, obvious cracks appear in the chips, and the saw teeth exhibit an overall inclined shape. At the feed rates of 0.05, 0.10 and 0.15 mm/r, the relative errors of the predicted minimum chip thickness are respectively 17.66%, 8.66% and 5.07%, the maximum chip thickness compression ratios are respectively 2.82, 2.78 and 2.61, and the chip serration degrees are respectively 0.12, 0.36 and 0.42. The slip line field model effectively predicts the variation of chip thickness with cutting parameters. With the increase in cutting speed and feed rate, the chip thickness compression ratio shows a decreasing trend, while the serration degree increases with a gradually slowing trend. Additionally, the influence of the tool edge radius on chip formation was analyzed through finite element simulation, and the effectiveness of the theoretical model for saw tooth-shaped chip formation was verified.