Research On Influence Of Guide Roll System To Stability Of Ring Rolling

In the ring rolling process, the structure of ring rolling mill, rolling process parametersand ring parameters all have important influence on the success of ring rolling progress. In allinfluencing factors, structure of guide roll system is very important to ensure the quality of thering and maintain the stability of the rolling process. If the guide roll forces or their appliedposition are unreasonable, the ring may be deformed unexpectedly or squashed to be wasteproduct. Therefore, studies on the stability of ring rolling and the guide roll system have veryimportant significance.Plastic instability influencing factors of the radial ring rolling are analyzed in thedissertation. The ring is subjected to the combined action of rolling deformation and guiderolls in radial ring rolling process. Mechanics analyses are carried out on the ring in those twocases respectively. Equations of ring’s bending moments in rolling process are developedbased on the mechanical model. Then the stress of ring at any point is analyzed and themaximum stress is found out. The plastic instability criterion of radial ring rolling is alsoproposed based on the analyses above.In radial-axial ring rolling, speed matching relationship has important influence on thestability of ring rolling. When main roll rotation and axial roll rotation are not matched,tangential friction force, which will acts on the ring, will be produced. When ring grownspeed and axial roll back speed are not matched, radial friction force will be produced andacts on the ring also. Mechanics analyses are carried out on the ring in these two casesrespectively. The influencing factors of radial-axial ring rolling are comprehensivelyconsidered, the stress equation of ring at any point is also analyzed. At last, the plasticinstability criterion of radial-axial ring rolling is proposed.Based on the theory of orthogonal optimization, process parameters of ring rolling areresearched. Experiment index is the maximum stress of ring, and the main influencing factorsare guide roll force, embracing angle, the feed rate of per revolution and ring radius. Throughthe analysis of orthogonal test, the primary and secondary order of every influencing factor toexperiment index is obtained. Degree of significant impact of every influence factor is gainedalso. Guide roll force, embracing angle, radius, interaction of ring radius and the guide rollforce are highly significant factors to the maximum stress of ring. Interaction of guide rollforce and embracing angle is significant to the maximum stress of ring. Substitution of thering rolling parameters into stress equation, the influencing law of every factor to the ring stress is found out also.Guide roll force is the most important influencing factor which effect ring rollingstability. Based on the theoretical results and the data of the D53K-2500A axial-radial ringrolling, the equation of embracing angle with the radius of outer ring is analyzed. Theembracing angle decreases with the ring increase. And then, the allowable maximum guideroll force is obtained also. The maximum guide roll force decreases sharply with the increaseof the radius of the ring. Analyses and conclusion gotten above have strong guidingsignificance to control guide roll force in ring rolling production.