A criterion for void closure in large ingots during hot forging

Zhang, Xiaoxun; Cui, Zhenshan; Wen, Cuié; Li, Yan

doi:10.1016/j.jmatprotec.2008.04.051

Cited by 102 publications

(54 citation statements)

References 40 publications

(60 reference statements)

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“…The upsetting operation has been carefully studied in recent research [24,[26][27][28] for identification of effective quality control parameters for the operation. Upsetting with flat plates is the most widely used method for disc forming.…”

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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“…Zhang's semi analytical void closure model [4] was selected as a base model to calculate void closure for large size ingots. The volumetric strain rate function, Eq.4, is obtained in order to account for void shape evolution which is essentially a factor to the specific material's macroscopic strain and internal stress state histories.…”

Section: Void Closure Modelmentioning

confidence: 99%

“…al. [4] propose a semi-analytical formulation of the volumetric strain rate and relative void closure for the introduction of void closure models. Both indicators are dependent of physically interpretable notions such as material influence, n , triaxiality state, x T and accumulated deformation in-billet, e E .…”

Section: Introductionmentioning

confidence: 99%

Analysis of Void Closure during Open Die Forging Process of Large Size Steel Ingots

Harris

Shahriari

Jahazi

2016

KEM

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Abstract. Large size forged ingots, made of high strength steel, are widely used in aerospace, transport and energy applications. The presence of internal voids in the as-cast ingot may significantly affect the mechanical properties of final products. Thus, such internal defects must be eliminated during first steps of the open die forging process. In this paper, the effect of in-billet void positioning on void closure throughout the ingot breakdown process and specifically the upsetting step in a large ingot size steel is quantitatively investigated. The developed Hansel-Spittel material model for new high strength steel is used in this study. The ingot forging process (3D simulation) was simulated with Forge NxT 1.0 ® according to existing industrial data. A degree of closure of ten virtual existing voids was evaluated using a semi-analytical void closure model. It is found that the upsetting process is most effective for void closure in core regions and central upper billet including certain areas within the dead metal zone (DMZ). The volumetric strain rate is determined and two types of inertial effects are observed. The dependence of void closure on accumulated equivalent deformation is calculated and discussed in relation to void in-billet locations. The original combination of information from both relative void closure and the volumetric strain rate provides a way to optimize the forging process in terms of void elimination.

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“…Moreover, quantitative evaluation of closure behavior by using a parameter was attempted in a report which stated that closure behavior can be arranged by the stress and strain fields obtained from these analyses. [17][18][19] In rolling, quantification of closure behavior is influenced by the arc-of-contact length or average plate thickness, so that estimation from the roll gap shape factor is also possible. Therefore, estimation of the closure effect by using the arc-of-contact length as a parameter is proposed.…”

Section: )mentioning

confidence: 99%

Effect of Groove Shape on Closure of Center Defects in Symmetric Rolling of Round Billets

Katsumura¹,

Kato²,

2015

ISIJ Int.

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Although the closure of defects at the center of round billets on rolling such billets is an important subject, a method of quantity evaluation for such closure has not yet been clarified. Therefore, to explain the effect of rolling conditions including grooved shape, we carried out the experiments with round billet which has an artificial defect and finite element analysis, especially with respect to the integration of the hydrostatic stress Gm. The results showed that grooved shape affected the closure of center defect, and Gm could express the relationship between closure and rolling conditions without the consideration of the difference in the ratio of defect size and roll size. However we found that original Gm could not express the influence of the grooved shape, at the same time.

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A criterion for void closure in large ingots during hot forging

Cited by 102 publications

References 40 publications

New schemes of forging plates, shafts, and discs

New schemes of forging plates, shafts, and discs

Analysis of Void Closure during Open Die Forging Process of Large Size Steel Ingots

Effect of Groove Shape on Closure of Center Defects in Symmetric Rolling of Round Billets

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