Kinematic Analysis And Rolling Strategy For Radial-axial Rolling Of Large Rings

Variation rules of kinematic parameters are achieved through kinematic analysis of thelarge ring radial-axial rolling process. Slip between the ring and the roll is studied, so that amore precise rolling strategy is developed and the stability of rolling process is improved.Study results can simplify the process of pre-production, shorten design cycles, increaseproductivity, and save development costs.Up to now, the kinematic theory of radial-axial rolling process is put forward on the basisof ideal derivation. Large numbers of study results and actual production situation indicatethat the growing process of ring diameter is consecutive. In this case, there is no specificstrategy of roll feed and slid mechanism of rolling process is also rarely studied.Firstly, kinematic parameter equation of radial-axial rolling process is developed. Therolling process between the radial deformation zone and the axial deformation zone isdescribed by defining the growing speed of outer diameter and underdraught speed of coneroller. According to the initial size of the ring, related size parameters of the ring at somepoint are derived. Employing the principle of constant volume, the feed speed of mandrel roll,the rotational speed of main roller, the rotational speed and withdrawing speed of axial rollerare derived respectively.According to difference between tangential speed along the interface of the ring velocityand linear velocity of main roll, sliding can be divided into forward slip and backward slip.Through differences between tangential speed along the interface of the ring velocity andlinear velocity of main roll, slip rules of the radial ring rolling zone are studied and factorsaffecting the zone are explored.The mathematical model of axial ring rolling zone is established. Slip in the interface ofaxial ring rolling is comprehensively analyzed as the speed coincidence point between thering velocity and linear velocity of axial roll is the special one of the interface. The axial ringrolling zone can be divided into forward slip area and backward slip area. As the pointlocation changes, slip location of that point is also different. Following the ring rollingprocess, both the maximum forward slip coefficient and the maximum backward slipcoefficient of the axial interface are decreasing. Besides, relative slip between the ring and axial roll is improved gradually.The influence of matching relationship between the revolving speed of main roll and therevolving speed of axial roll on the slip of axial ring rolling zone is explored. Employing theprinciple of constant volume, matching relationship formula between the revolving speed ofmain roll and the revolving speed of axial roll is derived. By analyzing the revolving speedratio, matching diagram of the revolving speed is established. As the backward slip area islarger than the forward slip area, a stable ring rolling process and high quality rings can beachieved.Based on the sliding mechanism of the radial-axial ring rolling and equations ofkinematic parameters, a rolling strategy of the Φ1500mm ring is developed in accordancewith the growing speed curve of outer diameter and the underdraught speed curve of coneroller.