Plastic Instability Criterion of Radial Ring Rolling

2013 ◽  
Vol 690-693 ◽  
pp. 2352-2355 ◽  
Author(s):  
Zeng Hai Xu ◽  
Dong Zhao ◽  
Qiang Wang
Keyword(s):  
Maximum Stress ◽  
Waste Product ◽  
Bending Moment ◽  
Plastic Instability ◽  
Rolling Process ◽  
Ring Rolling ◽  
Instability Criterion ◽  
Combined Action ◽  
Ring Rolling Process ◽  
Rolling Deformation

The ring is subjected to the combined action of rolling deformation and guide rolls in radial ring rolling process. If the rolling process parameters are designed unreasonably, the ring may be deformed unexpectedly or squashed to waste product. In this article, equation of ring’s bending moment in rolling process is developed based on the mechanical model. Then the stress of ring at any point is analyzed and the maximum stress is found out. The plastic instability criterion of radial ring rolling is also proposed based on the analyses above.

Change of Plastic Hinge Position in Radial Ring Rolling without Guide-Roll

2010 ◽  
Vol 42 ◽  
pp. 30-34
Author(s):  
Yong Xing Hao ◽  
Su Juan Shi ◽  
Lv Yun Yang ◽  
Song Wei Yang
Keyword(s):  
Wall Thickness ◽  
Plastic Hinge ◽  
Position Angle ◽  
Rolling Process ◽  
Ring Rolling ◽  
Thickness Change ◽  
Plastic Deformation Process ◽  
Hinge Position ◽  
Ring Rolling Process ◽  
Rolling Deformation

Radial ring rolling is an unsteady plastic deformation process. Internal stress of the ring is foundation of formation of the plastic hinge. The radial wall thickness of ring changes gradually along ring circumferential direction. Theoretical analysis and FE simulation show that: the plastic hinge is not always exactly opposite to the rolling deformation zone in ring rolling process without guide-roll. The plastic hinge position angle β0 is affected by ratio of rolling entrance wall thickness H0 and rate of wall thickness change η. Curve of β0-H0/η is shaped as double U staggered relative to each other. With the H0/η increasing, β0 reduces gradually and approaches to π in the range of H0/η>6.28. H0/η>14.6H0/R2. Only when the rolling process is steady, and H0≈R2, β0 is greater than π, and approximates to π. The β0 fluctuates dramatically when H0/η≈5.71. In some cases, H0/η may fluctuate in 0 to 6.28, leading to the instability of plastic hinge position.

Key Technologies for 3D-FE Modeling of Radial-Axial Ring Rolling Process

2008 ◽  
Vol 575-578 ◽  
pp. 367-372 ◽  
Author(s):  
L.G. Guo ◽  
He Yang
Keyword(s):  
Modeling And Simulation ◽  
Optimum Design ◽  
Rolling Process ◽  
Ring Rolling ◽  
Fe Modeling ◽  
Precise Control ◽  
Key Technologies ◽  
Axial Ring ◽  
Forming Characteristics ◽  
Ring Rolling Process

Nowadays, 3D-FE Modeling and simulation is an indispensable method for the optimum design and precise control of radial-axial ring rolling process for its complexities. In this paper, the unique forming characteristics of radial-axial ring rolling have first been summarized, and then some key technologies for 3D-FE modeling of the process have been presented and their solution schemes have been given out, lastly the modeling and simulation of radial-axial ring rolling process have been realized using elastic-plastic dynamic explicit procedure under ABAQUS environment. The work provides an important basis and platform for the future investigations, such as forming mechanism and laws, process optimum design and precise control.

Effect of the Guide-Roll Positional Angle to the Stability of Radial Ring Rolling

2007 ◽  
Vol 561-565 ◽  
pp. 1875-1878 ◽  
Author(s):  
Yong Xing Hao ◽  
Lin Hua ◽  
Gui Shan Chen ◽  
Dao Ming Wang
Keyword(s):  
Position Angle ◽  
Rolling Process ◽  
Ring Rolling ◽  
Positional Angle ◽  
The Mean ◽  
The Stability ◽  
Ring Rolling Mill ◽  
Ring Rolling Process ◽  
Ring Blank ◽  
Evaluating Method

Non-stability factors affect stability of radial ring rolling process, and lead to fluctuating of ring position. This decreases rolling precision. Evaluating stability of the process is very important. A stability evaluating method is proposed. The stability can be measured with the mean square root of sequence of oscillation of ring geometrical centerline displacement. Using ABAQUS/Explicit, the stability is analyzed. It is showed that guide-roll position angle has the significant effect to the stability. If guide-roll is located at the tangential position to the ring’s fringe, the stability will vary with the angle between two planes. One passes through axes of guide roll and ring blank, and another passes through axes of drive roll and ring blank. The stability is highest when guide roll is situated at the position angle of 100˚to 130˚at exit side of ring rolling mill.

scholarly journals Investigation of Slip Occurrence in the Ring Rolling Process

2019 ◽  
Vol 291 ◽  
pp. 02006
Author(s):  
Andrzej Gontarz ◽  
Piotr Surdacki
Keyword(s):  
Wall Thickness ◽  
Failure Modes ◽  
Rolling Process ◽  
Ring Rolling ◽  
Thickness Reduction ◽  
Main Stage ◽  
Forming Process ◽  
Limit Values ◽  
Ring Shape ◽  
Ring Rolling Process

Ring rolling is a hot forming process for producing rings that have large diameters when compared to their cross sections. This process is very dynamic and involves considerable variations in ring shape and size. One of the failure modes in ring rolling processes is slip that occurs when a thickness reduction, exceeds the limit value. The thickness reduction depends on the tool speed and dimensions as well as ring size, and varies over time. This paper reports results of a study investigating the thickness reduction with respect to slip occurrence. In terms of wall thickness reduction, the process can be divided into three distinct stages (excluding the sizing stage): (i) initial stage corresponding to the first revolution of the roll, (ii) main stage, when the proper ring rolling takes place, (iii) final stage, when the main roll does not move in an axial direction but the ring is being formed during one revolution of the tool. It has been found that the most slip-prone moment is the end of the second and the beginning of the third stage of the ring rolling process, when the wall thickness reduction is the highest. Based on a comparison of the calculated thickness reduction and its limit values, it could be predicted whether slip would occur, and if so – in what stage of the rolling process. Numerical results and experimental findings are in good agreement.

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