Modeling and application of ring stiffness condition for radial-axial ring rolling

Loss of circularity when creating metal ring-shaped products by ring rolling is a significant industrial issue. This paper explores the previously tacit knowledge that plastic changes in curvature-required to maintain circularity-principally occur as material passes through the roll gap. Through a series of experiments and numerical simulations on half-ring workpieces, the 'free curvature change' is explored for the first time, finding that the ring can 'curl up'-the radius reducing by as much as-39% in a single pass-unless the inner roll is much smaller than the outer roll. An analytical model of free curvature change is proposed based on force equilibrium and compatibility. Under a range of 'normal' operating conditions this predicted free curvature change to within 7%. In (full) ring rolling the radius of curvature must continually increase. This paper proposes that regulation of curvature is achieved through bending moments at the roll entry and exit; largest when the tool size ratio is furthest from the optimum. This hypothesis is supported by Finite Element simulations of full ring rolling, finding entry and exit moments up to a quarter of the moment for a fully plastic hinge. This work could be of direct use to process designers in choosing tool sizes and guide roll force limits and suggests new ways to use guide rolls to better maintain circularity in challenging situations.

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“…In ring rolling it is known that the guide rolls play a role in regulating curvature change. Hua et. al.…”

Section: Figmentioning

confidence: 99%

Curvature development in ring rolling

Cleaver

Allwood

2019

Journal of Materials Processing Technology

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“…Hua et al [ 3 , 4 ] analyzed the extremum parameters and ring stiffness condition in ring rolling. The deformation behaviors and blank design of profile ring rolling were also thoroughly analyzed [ 5 , 6 , 7 ]. Yang et al [ 8 ] presented the effects of blank size on the uniformity of strain and temperature distribution during hot rolling.…”

Section: Introductionmentioning

confidence: 99%

Influence of Plastic Deformation on Microstructural Evolution of 100Cr6 Bearing Ring in Hot Ring Rolling

2020

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The hot ring rolling technology as the crucial procedure for the manufacture of bearing rings plays an important role in determining the final microstructure of bearing rings. In this work, the influence of the hot ring rolling process on the microstructural evolution of 100Cr6 bearing rings was investigated using a three-dimensional (3D) numerical model and microstructural characterization. It was found that the significant microstructural refinement occurs at the different regions of the rings. However, owing to the non-uniform plastic deformation of hot rolling, the refinement rate of grain size and decrease of pearlite lamellar spacing (PLS) also showed uniformity at different regions of the rings. Furthermore, the degree of grain refinement had been limited with the increase of rolling reduction. Due to the refined grain size and decreased PLS, the Vickers hardness increased with the increase of rolling reduction. Moreover, the Vickers hardness from the outer surface to the inner surface of the ring is asymmetrical u-shaped, which had the law of lower hardness in the center area and higher hardness on the surface.

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“…Wang [20] proposed a process virtualization with a program based on an optimization of objective functions whose target is to control the motion of the Guide and Axial rolls. A mathematical model of the ring stiffness condition for Radial Axial Ring Rolling was established by Hua [21] based on the stiffness model, by introducing a control method of the pressure in the hydraulic cylinder to adjust the guiding force. Yang [22] developed a method to control the Guide rolls by the hydraulic adjustment mechanism with a 3D-FE Ring Rolling model, based on the optimal parameter design of the linkage assembly and critical pressure of the hydraulic ram.…”

Section: Introductionmentioning

confidence: 99%

Ring Rolling speed rolls optimization to improve ring quality and reduce production time

Allegri¹,

Giorleo²

2020

JMES

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In this paper, an analysis of the production time reduction as a function of the Idle and Axial rolls speed law in a Ring Rolling process was examined. Starting from an industrial case study, the authors defined a new milling curve able to produce a better ring quality with lower loads. From this result, the authors tested the effect of the production time reduction till the 40% of the initial one. The Ide roll velocity was varied in a range between 0.71 and 1.13 mm/s while the Axial roll between 0.35 and 1.70 mm/s. Geometrical and load parameters have been taken into account to compare the results achieved. The authors identified in the external ring diameter and in the Idle roll maximum load the most critical parameter to control; in particular, a break-even point was determined in order to select a set of rolls speed laws able to produce a good quality ring with lower production time (about 20%) and lower loads (about 10 %). In this research both experimental and numerical approaches were followed.

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Modeling and application of ring stiffness condition for radial-axial ring rolling

Cited by 39 publications

References 36 publications

Curvature development in ring rolling

Curvature development in ring rolling

Influence of Plastic Deformation on Microstructural Evolution of 100Cr6 Bearing Ring in Hot Ring Rolling

Ring Rolling speed rolls optimization to improve ring quality and reduce production time

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