Theoretical and laboratory modelling of the closure of metallurgical defects during forming of a forging

Banaszek, G.; Stefanik, A.

doi:10.1016/j.jmatprotec.2006.04.023

Cited by 71 publications

(69 citation statements)

References 5 publications

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“…There are known works, which describe the influence of specially shaped tools on the strain-stress state of the billet during open die forging [14][15][16][17][18]. These works are focused on forging by rounded and trapezoidal tools.…”

Section: Introductionmentioning

confidence: 99%

New schemes of forging plates, shafts, and discs

Zhbankov

Perig

Aliievа

2015

Int J Adv Manuf Technol

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This paper presents the various ways of forging large forged pieces such as shafts, plates, and discs. A finite element method was used to simulate open die forging processes such as forging by flat dies with a slant, forging by staged dies, and upsetting of profiled workpiece. The parameters of the stress strain state of the billet in these processes were determined, along with the rational parameters for forging plates by flat dies with slant such as tool size and mechanical modes. The optimal die step dimension and mechanical regime for forging shafts by staged tools was determined. Also, the rational geometric parameters of the workpiece for forging discs by upsetting were determined. For these forging schemes, a simulation was done of the microstructure evolution in forgings obtained by traditional technology and new proposed technology. The paper shows the advantages of new forging schemes which provide a uniform distribution of grain size in the obtained billets.

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Section: Introductionmentioning

confidence: 99%

New schemes of forging plates, shafts, and discs

Zhbankov

Perig

Aliievа

2015

Int J Adv Manuf Technol

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“…The sole knowledge of the change in deformed metal shape and the deformation indices is not sufficient for the correct development of the tool shape and the process technology itself. The theoretical determination of the local velocity fields and the peculiarities of the deformed metal plastic flow, while considering the metal temperature, movement speed, changes in metal flow stress values and the friction conditions on the metal and tool contact surfaces makes it possible to considerably speed up and more efficiently design the technological process and to reduce the cost and time-consuming of empirical studies necessary for starting up the manufacture of new products [8][9][10]. Furthermore, by utilizing numerical computation results, the possibility of formation of many defects could be reduced to a considerable extent.…”

Section: Introductionmentioning

confidence: 99%

Increasing the Durability of Separating Rolls During Rolling Ribbed Bars in the Three-Strand Technology

Strycharska¹,

Szota²,

Mróz³

2017

Archives of Metallurgy and Materials

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The paper presents the results of investigations aimed at enhancing the durability of slitting passes in the process of three-strand rolling of 16 mm-diameter ribbed bars. Using the Forge2011® computer program, numerical modelling of the rolling process was carried out in order to examine the variations in band shape in individual rolling passes, to verify the correctness of the designed new slitting pass system, to determine the local strains in the rolled band, and then to determine the distribution of unit friction force work on the roll groove surface.From the obtained investigation results it was found that the application of the new roll pass design in stands 13-16 increased their durability in the rolling process by approx. 30%. The wear of the roll sets for the stands under examination after rolling out the annual 16 mm-diameter bar production volume was determined in the study. The obtained numerical modelling results were verified in experimental tests.

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“…It is believed that the stress state in the stagnant deformation zone at the end of forging is hydrostatic pressure, where the shear stress can exceed critical shearing strength of material, and laminated shear crack parallel to the section appears where the shear deformation is very significant, namely reaching the critical condition. However, most investigations on heavy forging defects in the upsetting process focus on both the surface crack [16][17][18] and closing/bonding of inner void [19][20][21][22][23][24] of the forgings in recently years. Based on the above, there is not a uniform interpretation to the inner laminated crack of large forgings and its criterion model yet.…”

Section: Introductionmentioning

confidence: 99%

“…In the past years, commercial FEA software MARC was used to simulate the closing process of the inner crack in cylindrical body during hot upsetting, analyse the stress and strain of the crack during deformation, and various factors that affect closing and bonding of the inner crack [25] . Banaszek [19,20] studied the upsetting process of a cylinder with a void by the commercial FEA software Forge and through simulation investigate the influence of forging processing on the internal void closure of the forgings and gain the reasonable forging conditions of defect-free. Based on DEFORM software, the coupling thermal-mechanical model of upsetting process was established separately by Zhang [17] and Huang [26] , and to investigate the effect of upsetting parameters on centre compaction and void changing.…”

Section: Introductionmentioning

confidence: 99%

Analysis of laminated crack defect in the upsetting process of heavy disk-shaped forgings

Wang

et al. 2016

Engineering Failure Analysis

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Using nonlinear finite element method, a thermo-mechanical coupled simulation model for the formation mechanism of the laminated crack defect has been established in the upsetting of heavy disk-shaped forgings. Through numerical simulation, the distributions of stress, equivalent strain and strain rate were analysed. Meanwhile the distribution diagram of stress state evolution was obtained, and the uncoordinated deformation, under tri-lateral compression, is determined as the main reason leading to laminated crack defect. To reveal the characteristics of the uncoordinated deformation, the variations of each variable and its gradient in numerical simulation were presented, and a combined prediction model of laminated crack defect were proposed based on degree of deformation and gradient of deformation speed. Subsequently, the morphology and distribution of laminated crack were obtained in the centre of forging using the prediction model. Comparison of calculation results and experimental data indicates that both of them match well. In addition, the effect of friction coefficient on the deformation is also presented. The results show that the decreasing of friction coefficient is an effective measure to restrain the laminated crack defect. Abstract: Using nonlinear finite element method, a coupling thermo-mechanical simulation model for the formation mechanism of the laminated crack defect has been established in the upsetting of heavy disk-shaped forgings. Through numerical simulation, the distributions of stress, equivalent strain and strain rate were analyzed. Meanwhile the distribution diagram of stress state evolution was obtained, and the uncoordinated deformation, under tri-lateral compression, is determined as the main reason leading to laminated crack defect. To reveal the characteristics of the uncoordinated deformation, the variations of each variable and its gradient in numerical simulation were presented, and a combined prediction model of laminated crack defect were proposed based on degree of deformation and gradient of deformation speed. Subsequently, the morphology and distribution of laminated crack were obtained in the centre of forging using the prediction model. Comparison of calculation results and experimental data indicates that both of them match well. In addition, the effect of friction coefficient on the deformation is also presented. The results show that the decreasing of friction coefficient is an effective measure to restrain the laminated crack defect.

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Theoretical and laboratory modelling of the closure of metallurgical defects during forming of a forging

Cited by 71 publications

References 5 publications

New schemes of forging plates, shafts, and discs

New schemes of forging plates, shafts, and discs

Increasing the Durability of Separating Rolls During Rolling Ribbed Bars in the Three-Strand Technology

Analysis of laminated crack defect in the upsetting process of heavy disk-shaped forgings

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