Research on Edge Cracks of the Ring Part During Ring Rolling Based on Cast Blank

2015 ◽  
Author(s):  
Huiping Qi ◽  
Yongtang Li ◽  
Xiaojian Wei ◽  
Li Ju ◽  
Dongsheng Qian
Keyword(s):  
Rolling Process ◽  
Ring Rolling ◽  
Feed Speed ◽  
Forming Process ◽  
The Core ◽  
Initial Stage ◽  
Initiation And Propagation ◽  
New Process ◽  
Edge Cracks ◽  
Ring Rolling Process

The casting-rolling compound forming process is a new process to produce seamless ring shaped components. In the new process, the input blank for the new process is a ring shaped casting blank. Edge crack affects severely the quality of rolled ring parts in ring rolling process based on cast blank. Theoretical analysis, numerical simulation and experiments were combined to study the edge crack and its prevention methods during ring rolling. Conclusions are obtained that: (1) for casting blank, the initial stage of ring rolling is crucial to prevent the initiation and propagation of the edge cracks. (2) in the ring rolling process, the occurrence of cracks were influenced mainly by rolling temperature and feed speed of the core-roller. Cracks could be avoided by controlling above two rolling parameters. (3) in the initial stage of ring rolling, higher rolling temperature and lower feed speed of the core-roller are beneficial to improve the plasticity of the materials and restrain effectively the initiation and propagation of cracks. The work is a part of the research of the new casting-rolling compound forming process. It will promote the development of the new process.

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.

Investigation on Constant and Variable Feed Speeds Effects in Ring Rolling Process Using 3D FEM

2011 ◽  
Vol 264-265 ◽  
pp. 1776-1781 ◽  
Author(s):  
Nassir Anjami ◽  
Ali Basti
Keyword(s):  
Finite Element ◽  
Rolling Process ◽  
Ring Rolling ◽  
Outer Diameter ◽  
Fe Model ◽  
Feed Speed ◽  
3D Fem ◽  
Cold Ring Rolling ◽  
Plastic Deformation Behavior ◽  
Ring Rolling Process

Although cold ring rolling (CRR) process is largely used in the manufacturing of profiled rings like bearing races, research on this purpose has been scant. In this study, based on a validated finite element (FE) model, CRR process is simulated regarding the variable and constant feed speeds of the mandrel roll which lead to constant and variable values of the ring's diameter growth rates respectively using a 3D rigid-plastic finite element method (FEM). Major technological problems involved in the process including plastic deformation behavior, strain distribution and its uniformity, Cockcroft and Latham damage field and final outer diameter of ring are fully investigated. The results of simulations would provide a good basis for process control especially feed speed controlled mills and guiding the design and optimization of both cold and hot ring rolling process.

Speed Idle Roll Law Optimization in a Ring Rolling Process

2015 ◽  
Vol 651-653 ◽  
pp. 248-253 ◽  
Author(s):  
Luca Giorleo ◽  
Elisabetta Ceretti ◽  
Claudio Giardini
Keyword(s):  
Rolling Process ◽  
The Other ◽  
Ring Rolling ◽  
Hot Forming ◽  
External Diameter ◽  
Roll Speed ◽  
Forming Process ◽  
Industrial Environment ◽  
Ring Rolling Process

Ring Rolling is a complex hot forming process where different rolls are involved in the production of seamless rings characterized by extreme dimensions (i.e. external diameter higher more than 1m). Because each roll can be independently controlled from the other ones different speed laws must be set; usually, in the industrial environment, a milling curve is introduced to monitor the shape of the workpiece during the deformation in order to ensure a correct ring production. In former works the authors focused their attention on the influence of different milling curves for an industrial case and the results underlined that a ring produced with a good quality and lower loads and energy could be obtained imposing a linearly descending trend to the Idle roll speed law. However different approaches could be used in order to evaluate the mentioned speed law.In this work the authors enhanced the knowledge about the optimization of the Idle roll speed law: different Idle roll speed laws were designed and simulated and the results were compared in order to identify the best speed law that guarantees a good quality ring with lower loads and energy required for manufacturing.

Application of a Material Model to Predict Rolling Forces and Microstructure during a Hot Ring Rolling Process

2013 ◽  
Vol 762 ◽  
pp. 354-359 ◽  
Author(s):  
Thomas Henke ◽  
Gerhard Hirt ◽  
Markus Bambach
Keyword(s):  
Grain Size ◽  
Microstructure Evolution ◽  
Rolling Force ◽  
Flow Behavior ◽  
Rolling Process ◽  
Ring Rolling ◽  
Experimental Investigations ◽  
Forming Process ◽  
Ring Geometry ◽  
Ring Rolling Process

Ring rolling is an incremental bulk forming process. Hence, the process consists of a large number of alternating deformations and dwell steps. For accurate calculations of material flow and thus ring geometry and rolling forces in hot ring rolling processes, it seems necessary to consider material softening due to static and post dynamic recrystallization which could occur between two deformation steps. In addition, due to the large number of cycles, the modeling results, especially the prediction of grain size, can easily be affected by uncertainties in the input data. However, for small rings and ring material with slow recrystallization kinetics, the interpass times can be short compared to the softening kinetics and the effect of softening can be so small, that microstructure evolution and the description of the materials flow behavior can be de-coupled. In this paper, a semi-empirical JMAK-based model for a stainless steel (1.4301/ X5CrNi18-9/ AISI304) is presented and evaluated by the use of experiments and other investigations published in [1],[2]. Finite Element (FE) simulations of a ring rolling process with a high number of ring revolutions and thus multiple, incremental forming steps were conducted based on ring rolling experiments. The FE simulation results were validated with the experimentally derived rolling force and evolution of ring diameter. The microstructure evolution was calculated in a post processing step considering the investigated evolution of strain and temperature. In this calculation the interrelations between the fraction of dynamically recrystallized microstructure, the evolution of post-dynamically recrystallized microstructure and the final grain size have been considered. Both, the calculated final microstructure and the evolution of rolling force and ring geometry calculated stand in good agreement with the experimental investigations.

An Analytical Approach to Ring Rolling Using Modified Slab Analysis

2011 ◽  
Vol 383-390 ◽  
pp. 4634-4641
Author(s):  
Ali Parvizi ◽  
Karen Abrinia ◽  
Mohsen Hamedi
Keyword(s):  
Friction Factor ◽  
Rolling Process ◽  
Ring Rolling ◽  
Shear Stresses ◽  
Feed Speed ◽  
Shear Yield ◽  
Experimental Works ◽  
Ring Rolling Process ◽  
Good Agreement ◽  
Normal And Shear Stresses

In this paper, based on the modified slab method theory, an analytical solution for ring rolling process is presented. The non-uniformity of the normal and shear stresses across the section of the deforming material are considered. The friction factor multiplied by the shear yield strength is used to present friction between the main roll and the ring. Complete expressions for the ring rolling pressure, force and torque are obtained and the position of neutral point is predicted. The influence of the process parameters such as friction factor, main roll rotational speed, feed speed, and others was investigated. Analytical results obtained from the present formulation were compared to previous experimental works and good agreement and improvements were observed.

scholarly journals Establishment of Thermal Ductile Fracture Criterion for As-Cast 42CrMo Steel and Its Application in Hot Ring Rolling Process

2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Yuanyuan Chen ◽  
Huiping Qi ◽  
Yongtang Li ◽  
Lin Hua
Keyword(s):  
Ductile Fracture ◽  
Fracture Criterion ◽  
Fracture Strain ◽  
Rolling Process ◽  
Ring Rolling ◽  
Ductile Fracture Criterion ◽  
Forming Process ◽  
42Crmo Steel ◽  
Critical Fracture ◽  
Ring Rolling Process

The casting-rolling compound forming process of ring parts is an advanced plastic forming technology that has been developed due to the merits of high efficiency and energy and material saving. However, cracks often occur during the hot ring rolling process, especially at the edges of the ring parts, which severely affects the forming quality. To predict and try to avoid the occurrence of cracks in the casting-rolling compound forming process of ring parts, the high-temperature fracture behaviors of as-cast 42CrMo steel were investigated by thermodynamic experiment method. The high-temperature tensile tests were carried out using the Gleeble-3500D thermomechanical simulator at various temperatures and strain rates. Stress-strain curves and fracture morphology were examined, through which the sensitivity of stress to temperature and strain rate and the effect of dynamic recrystallization and cavity evolution on fracture were found. The law of critical fracture strains was analyzed, and the model of critical fracture strain as a function of temperature and strain rate was established. Based on Oyane criterion, the thermal ductile fracture criterion was established in conjunction with the model of critical fracture strain. By embedding this thermal damage model into the finite element (FE) model for hot ring rolling of an as-cast 42CrMo ring, the damage prediction for this process was realized, and the thermal ductile fracture criterion was proved to be reliable. From the FE results for hot ring rolling, mechanism of damage and fracture in the hot ring rolling process was analyzed. The damage threshold C f is small, and the damage ratio D is large at the top and bottom edges of the inner surface area of the ring, which have the greatest propensity to cracking in the course of hot ring rolling. This is of great significance in terms of improving the forming quality of ring parts in the casting-rolling compound forming process.

FE Analysis of Microstructure Evolution during Ring Rolling Process of a Large-Scale Ti-6Al-4V Alloy Ring

2010 ◽  
Vol 638-642 ◽  
pp. 223-228 ◽  
Author(s):  
Jong Taek Yeom ◽  
Jeoung Han Kim ◽  
Jae Keun Hong ◽  
Nho Kwang Park ◽  
Chong Soo Lee
Keyword(s):  
Grain Size ◽  
Prediction Model ◽  
Microstructure Evolution ◽  
Large Scale ◽  
Volume Fraction ◽  
Rolling Process ◽  
Ring Rolling ◽  
Forming Process ◽  
Microstructure Prediction ◽  
Ring Rolling Process

Microstructure evolution during ring rolling process of a large-scale Ti-6Al-4V ring was investigated with the combined approaches of three dimensional finite element method (FEM) simulation and microstructure prediction model. A microstructure prediction model was established by considering the volume fractions and grain size of  and  phases varying with process variables, and grain growth. In order to perform FE simulation for ring rolling process of Ti-6Al-4V alloy, a constitutive equation was generated by utilizing the flow stress data obtained from hot compression tests at different temperature and strain rate conditions. The volume fraction and grain size of  and  phases during ring rolling were calculated by de-coupled approach between FEM analysis and microstructure prediction model. The prediction results were compared with the experimental ones. Our proposed microstructure simulation module was useful for designing hot forming process of Ti-6Al-4V alloy

Investigation of cavity filling in profile ring rolling process for T-shape ring

2021 ◽  
pp. 146442072110075
Author(s):  
Hosein Zayadi ◽  
Ali Parvizi ◽  
Hamid Reza Farahmand ◽  
Davood Rahmatabadi
Keyword(s):  
Rotational Velocity ◽  
Element Model ◽  
Rolling Process ◽  
Ring Rolling ◽  
Feed Speed ◽  
Filling Rate ◽  
Roll Torque ◽  
Axial Forces ◽  
Cavity Filling ◽  
Ring Rolling Process

In this paper, key parameters affecting the cavity filling in single and double T-shape profile rings are comprehensively investigated via numerical and experimental analysis. A three-dimensional finite element model was developed in Abaqus\Explicit to assess the influence of crucial ring rolling process parameters, including feed speed, main roll rotational velocity, the existence and the absence of axial rolls on the cavity filling of single and T-shape rings and the main roll torque. Besides, a ring rolling machine was built to conduct practical experiments and validate the numerical evaluation, while for the first time, the role of the axial roll and the main roll torque on the quality of the cavity filling is experimentally evaluated. Power requirements and the final ring profile geometry were obtained by the simulation method, and the results were confirmed by the experiments. The results showed that axial rollers significantly reduced the cavity filling rate, and in contrast, the effect of mandrel feed speed and the main roll rotational velocity was much lower. Also, the axial forces were considerably less than the radial forces. However, the rolling operation was done in both radial and axial directions. The existence of axial rolls had an intensive effect on the process’ required power, as a result the main roll torque increased more than three times in case of applying axial rolls, compared with not considering them. Severe effects of axial rollers on increasing force and decreasing cavity filling rate can be attributed to frictional forces between the ring and axial rolls, restricted ring motion, which has to be compensated by a higher torque of the main roll. When the axial rolls are used, the material flow in the ring’s height direction is restricted. Therefore, the material cannot move easily to form the profile. All experimental and simulation results, including mandrel force, cavity filling, and ring profile geometry, were in good agreement, and in all cases, the simulation error was less than 10%.

Speed Roll Laws Influence in a Ring Rolling Process

2013 ◽  
Vol 554-557 ◽  
pp. 337-344 ◽  
Author(s):  
Luca Giorleo ◽  
Elisabetta Ceretti ◽  
Claudio Giardini
Keyword(s):  
Numerical Approach ◽  
Rolling Process ◽  
Ring Rolling ◽  
Roll Speed ◽  
Forming Process ◽  
Industrial Case Study ◽  
Ring Shape ◽  
Deformation Processes ◽  
Ring Rolling Process

Ring Rolling is a complex hot forming process used for the production of shaped rings, seamless and axis symmetrical workpieces. The main advantage of workpieces produced by ring rolling, compared to other technological processes, is given by the size and orientation of grains, especially on the worked surface which give to the final product excellent mechanical properties. In this process different rolls (Idle, Axial, Guide and Driver) are involved in generating the desired ring shape. Because each roll is characterized by a speed law that could be set independently by the speed law imposed to the other rolls an optimization is more critical compared with other deformation processes. Usually in industrial environment a milling curve is introduced in order to correlate the Idle and Axial roll displacement, however it must be underlined that different milling curves lead to different loads and energy for ring realization.In this work an industrial case study was modeled by a numerical approach: different milling curves characterized by different Idle and Axial roll speeds laws (constant, linear and quadratic) were designed and simulated. The results were compared in order to identify the best set of Idle and Axial roll speed laws that guarantee a good quality produced ring (lower fishtail) with lower manufacturing loads and energy.

Feed Speed Design and Optimization in Radial-Axial Ring Rolling Process by FEM

2011 ◽  
Vol 421 ◽  
pp. 513-521
Author(s):  
Shi Biao Liu ◽  
Ke Lu Wang ◽  
Shi Qiang Lu ◽  
Xin Li ◽  
Xian Juan Dong
Keyword(s):  
Rolling Force ◽  
Effective Strain ◽  
Rolling Process ◽  
Ring Rolling ◽  
Fe Model ◽  
Feed Speed ◽  
Rigid Plastic ◽  
Axial Ring ◽  
Ring Rolling Process

Radial-axial ring rolling is an important component of advanced manufacturing technology, but it has characteristics of high nonlinear on geometry and physics, so the radial-axial ring rolling process becomes very complex. In addition, the feeding mode of core roller has enormous influence on the quality of the rolled ring as well as the stability of the process. In this paper, a 3D rigid-plastic FE model of radial-axial ring rolling process is established, then three kinds of feed speed design ((1)constant of feed speed; (2)constant of feed in one rotary; (3)variation of feed speed)are offered. The difference of outer radius growth velocity, distribution of effective strain and temperature, rolling force, size of ring are analysised for the three kinds of feed methods. And, an optimized feed method is proposed base on analytic results, the optimized feed method can improve the quality of formed ring, and decrease the requirement of ring rolling mill.

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