環(huán)形鍛件輾環(huán)成形的過程可分為環(huán)料咬人階段、穩(wěn)定成形階段、成形結(jié)束階段。在環(huán)料穩(wěn)定成形階段，進給速度和旋轉(zhuǎn)速度都不大，速度變化也較小，處于近似靜力平衡狀態(tài)。

　　The forming process of ring forging can be divided into ring material biting stage, stable forming stage and forming end stage. In the steady forming stage of ring material, the feed speed and rotational speed are little, and the speed change is small, and it is in the approximate static equilibrium state.

　　輾環(huán)類似軋鋼的穿孔輾壓成形，環(huán)形鍛件連續(xù)咬人孔型是使環(huán)料轉(zhuǎn)動并實現(xiàn)穩(wěn)定輾壓成形的必要條件。環(huán)料咬人孔型的力學(xué)模型如圖6—3—1所示。圖中，P1和T1分別為驅(qū)動輥對環(huán)料的正壓力和摩擦力，P2為芯輥對環(huán)料的正壓力(芯輥為空轉(zhuǎn)輥，它隨環(huán)料一起轉(zhuǎn)動，沒有摩擦力矩作用，所以芯輥對環(huán)料摩擦力的合力為零，而僅有正壓力)。

　　Ring piercing rolling is similar to steel rolling, and the continuous bite pass of ring forging is the necessary condition for the rotation of the ring and stable roll forming. The mechanical models of the ring pass are shown in figures 6 - 3 - 1. In the figure, P1 and T1 respectively to drive positive pressure and friction roller of ring material, P2 as the core and positive pressure on the ring material (core roller for idle roll, it rotates with the ring material, no friction torque, so the core roller ring material friction force is zero, and only positive pressure).

　　令a1和a2分別為驅(qū)動輥和芯輥與環(huán)料的接觸角，R1和R2分別為驅(qū)動輥和芯輥的工作半徑，h0和h1分別為環(huán)料在孔型人口處和出口處的壁厚，Ah=h0一h為環(huán)形鍛件在孔型中每轉(zhuǎn)壁厚減小量，n1為驅(qū)動輥轉(zhuǎn)速，L為接觸弧長在進給方向的投影長度。

　　A1 and A2 were the driving roller and the core roller and ring material contact angle, R1 and R2 respectively the working radius of driving roller and roller, H0 and H1 respectively in the ring material entrance and exit hole wall thickness, Ah=h0 h ring forgings in the pass thickness reduction per turn a small amount of N1, the drive roller speed, L projection length in the feed direction of the contact arc.

　　為使環(huán)形鍛件咬入孔型，則環(huán)料的拽入力必須大于或等于它的推出力，而進給方向環(huán)料的受力狀態(tài)是平衡的。

　　In order to make the circular forging bite into the groove, the pulling force of the ring material must be greater than or equal to its pushing force, and the force state of the feed direction ring material is balanced.