The Analysis of the Stress and Strain in Skew Rolling

Yang, Hai Bo; Zhang, Li Jie; Zheng, Huayan

doi:10.4028/www.scientific.net/amr.538-541.1650

Cited by 8 publications

(7 citation statements)

References 3 publications

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“…This can particularly be observed with respect to cross and skew rolling processes in which variable stresses occurring in the workpiece axis lead to fracture, a phenomenon which is known as the Mannesmann effect. As shown by Yang et al [26], in these processes, the material is prone to standard ductile fracture that can be predicted using the fracture criteria described with Eq. (1).…”

Section: Introductionmentioning

confidence: 99%

Rotary compression in tool cavity—a new ductile fracture calibration test

Pater

Tomczak

Bulzak

et al. 2020

Int J Adv Manuf Technol

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Ductile fracture is one of the most common failure modes in hot metal forming. It can be predicted by means of so-called damage functions that describe the relation between stress, deformation and fracture initiation. A practical use of these functions requires the knowledge of the critical damage value of the material that is determined by calibration tests based on compression, tension and torsion. For the prediction to be correct, one must ensure that the modelled and real stresses are in agreement. Previous studies did not offer any effective test for determining critical values of damage under changing load conditions that occur in cross and skew rolling processes, among others. To compensate for this knowledge gap, researchers at the Lublin University of Technology have developed a new test consisting in rotary compression of a test-piece in a cavity between the tools, which is described in this paper. In the proposed test, a cylindrical test-piece is rolled over a cavity (impression) created by grooves on two mating tools. The cavity height is smaller than the test-piece diameter. At the critical value of the forming length, the state of stress induced thereby in the test-piece axis causes fracture. Knowing the critical forming length, it is possible to determine the critical value of damage by numerical modelling. The practical application of the proposed test is illustrated through the case of C45 grade steel subjected to forming in the temperature range 950-1150°C. The analysis makes use of the normalized Cockcroft-Latham (NCL) criterion of ductile fracture.

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Section: Introductionmentioning

confidence: 99%

Rotary compression in tool cavity—a new ductile fracture calibration test

Pater

Tomczak

Bulzak

et al. 2020

Int J Adv Manuf Technol

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show abstract

“…To ensure good rolling results, the diameter of the billet should be approximately 3–4% smaller than the diameter of the balls. However, the diameter of the rolls should be 5–6 times bigger than the diameter of the balls [8,9,10,11,12,13,14].…”

Section: Introductionmentioning

confidence: 99%

The Effect of Process Parameters in Helical Rolling of Balls on the Quality of Products and the Forming Process

2018

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This paper presents selected numerical and experimental results of a skew rolling process for producing balls using helical tools. The study investigates the effect of the billet’s initial temperature on the quality of produced balls and the rolling process itself. In addition, the effect of billet diameter on the quality of produced balls is investigated. Experimental tests were performed using a helical rolling mill available at the Lublin University of Technology. The experiments consisted of rolling 40 mm diameter balls with the use of two helical tools. To determine optimal rolling parameters ensuring the highest quality of produced balls, numerical modelling was performed using the finite element method in the Forge software. The numerical analysis involved the determination of metal flow kinematics, temperature and damage criterion distributions, as well as the measurement of variations in the force parameters. The results demonstrate that the highest quality balls are produced from billet preheated to approximately 1000 °C.

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“…Aside from the above mentioned publications by the present author [5][6][7][8][9][10][11][12], there are only few other publications available on producing shafts [35][36][37] and balls produced by cold rolling [38][39][40].…”

Section: Application Of Fem For Analysis Of Helical Rolling Processesmentioning

confidence: 99%

FEM Analysis of the Multi-Wedge Helical Rolling Process for a Workholding Bolt

Pater

2016

MATEC Web Conf.

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Abstract. This paper presents the results of a numerical analysis of a helical rolling process for producing a 25 mm diameter workholding bolt using multi-wedge helical tools. The numerical modeling was performed by the finite element method (FEM) using the commercial simulation software Simufact.Forming v. 12. The modeling was performed in a three-dimensional state of strain and included a full thermal analysis. As a result, the changes in workpiece shape as well as the distributions of strains, temperature, damage, loads and torque were determined. The numerical results confirm that workholding bolts can be produced by multi-wedge helical rolling.

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The Analysis of the Stress and Strain in Skew Rolling

Cited by 8 publications

References 3 publications

Rotary compression in tool cavity—a new ductile fracture calibration test

Rotary compression in tool cavity—a new ductile fracture calibration test

The Effect of Process Parameters in Helical Rolling of Balls on the Quality of Products and the Forming Process

FEM Analysis of the Multi-Wedge Helical Rolling Process for a Workholding Bolt

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