Analytical relations between hardness and strain for cold formed parts

Sonmez, Fazıl O.; Demir, Ahmet

doi:10.1016/j.jmatprotec.2006.12.031

Cited by 107 publications

(48 citation statements)

References 53 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…As burnishing causes plastic deformation or flow of material along the feed (X) and step (Z) directions significantly, only residual stress along the X and Z directions is estimated, presented, and analyzed in this study. Note that hardness is indirectly estimated from the predicted plastic strain or deformation data, by using the relationship between the Vickers hardness HV and effective flow stress σ e of the material as [19]:…”

Section: Finite Element Modellingmentioning

confidence: 99%

See 1 more Smart Citation

Finite Element Analysis of Surface Integrity in Deep Ball-Burnishing of a Biodegradable AZ31B Mg Alloy

Uddin

Hall

Hooper

et al. 2018

Metals

View full text Add to dashboard Cite

Abstract:As an effective and affordable technique, deep ball-burnishing has been applied to induce the plastic deformation of material, thus resulting in an increased surface hardness, compressive residual stress, and finish quality. Recent research shows that the fast degradation of an Mg alloy implant is a prime limiting factor for its success in in vivo human trials. This paper presents a comprehensive investigation into deep ball-burnishing of a biodegradable AZ31B Mg alloy, in order to improve the alloy's surface integrity. A series of experiments using an in-house built burnishing tool with a 10-mm steel ball have been conducted, with a key focus of exploring the influence of the major process parameters-e.g., burnishing force (750-2650 N), feed rate (150-500 mm/min), and step-over (0.05-0.15 mm)-on hardness and finish quality. With the aim of performing a parametric sensitivity study, a three-dimensional (3D) finite element (FE) model is developed to predict the deformation mechanics, plastic flow, hardness, and residual stress. The FE model agrees with the experiment, hence validating the reliability of the model. Results show that while burnishing significantly improves surface integrity compared to the untreated surface, burnishing force and step-over are shown to be dominant. The net material movement dictates generated residual stress (tensile or compressive), often negatively affecting the surface integrity (e.g., surface cracks), which may be responsible for the onset of corrosion. An appropriate burnishing strategy must therefore be planned, in order to achieve the intended process outcome. The resulting surface properties, enhanced by the deep ball-burnishing, are expected to potentially increase the corrosion resistance of AZ31B Mg alloy implants.

show abstract

Section: Finite Element Modellingmentioning

confidence: 99%

“…presented, and analyzed in this study. Note that hardness is indirectly estimated from the predicted plastic strain or deformation data, by using the relationship between the Vickers hardness HV and effective flow stress e σ of the material as [19]:…”

Section: Finite Element Modellingmentioning

confidence: 99%

Finite Element Analysis of Surface Integrity in Deep Ball-Burnishing of a Biodegradable AZ31B Mg Alloy

Uddin

Hall

Hooper

et al. 2018

Metals

View full text Add to dashboard Cite

show abstract

“…Hardness as a measure of material's resistance to wear and permanent deformation is an important quality parameter for cold forged parts. Through estimating the hardness distribution, it is possible before manufacturing the components to predict whether the end product will have the desired hardness levels or require a final heat treatment [1]. The estimation of the hardness distribution can also facilitate the decision to complete the process in one or many stages with intermediary heat treatments.…”

Section: Introductionmentioning

confidence: 99%

Investigation of the Influence of Tool Geometry on Effective Strain Distribution in Full Forward Extrusion

Merklein

Ndzomssi

Engel

2011

AIP Conference Proceedings

View full text Add to dashboard Cite

Mechanical and thermal behaviors of nitrogen-doped Zr-Cu-Al-Ag-Ta--An alternative class of thin film metallic glass Appl. Phys. Lett. 101, 181902 (2012) Structural homogeneity of nanocrystalline VT1-0 titanium. Low-temperature micromechanical properties Low Temp. Phys. 38, 980 (2012) Influence of carbon content and nitrogen vacancies on the bonding structure and mechanical performance of graphite-like BCxN thin films J. Appl. Phys. 112, 063525 (2012) Hardness, yield strength, and plastic flow in thin film metallic-glass J. Appl. Phys. 112, 053516 (2012) Additional information on AIP Conf. Proc. Abstract. Due to strain hardening of the material, the hardness of cold forged parts is considerably improved. It is well known that the hardness of cold forged parts is closely related to its deformation, and that this relation is not dependent on the deformation process. The effective strain defines the local deformation, and can be determined in simulation of the cold forming process. In order to reach the required or to set specific hardness distribution with cold forging without any heat treatment processes, it is necessary to find out which manufacturing parameters influence the effective strain, and determine the effects of these parameters. The research work covered in this paper investigates the influence of the die geometry (as manufacturing parameter) on the effective strain. For that, a full forward extrusion process was modeled using the FE-software Simufact.Forming and three parameters of the die geometry, namely the deformation ratio, the shoulder radius and the opening angle were varied. The maximum effective strain from each combination is determined, and the effects of each considered parameter as well as the effects of interactions between these factors are checked.

show abstract

“…Following the work of Meyer [53], Tabor defined the representative strain at the contact edge of the spherical indentation and empirically determined the values of  and  as 2.8 and 0.2 based on a lot of tensile test data on common metals [42]. Most of researchers agreed with the formation of Tabor's equation, but disputed the choice of the value of  and  [56][57][58][59][60][61][62]. Nevertheless, some researchers argued the formulation of representative strain in Tabor's equation [51,60,68,69].…”

Section: Discussionmentioning

confidence: 99%

“…The strain constraint fact, , should vary with the depth of the indentation for which the tangent of corresponding contact point could be equal to the same angle of sharp indenter [6,55]. Most of researchers agreed with the formulation of Tabor's equation, but argued the choice of the value of  and  [56][57][58][59][60][61][62].…”

Section: Determination Of Plastic Property Through Spherical Indentatmentioning

confidence: 99%

Determining the elastic-plastic properties of metallic materials through instrumented indentation

Chang¹

View full text Add to dashboard Cite

AgradecimientosPrimero, me gustaria agradecer a mis supervisores. Me gustaría expresar mi máximo aprecio hacia mi supervisor Dr. J. Ruiz-Hervias por guiarme y ayudarme durante estos años en el laboratorio. He aprendido de él, no solo en lo estrictamente académico, si no en su generosidad y en su mente positiva hacia la vida. Además, también quería agradecer a mi co-supervisor Dr. M. A. Garrido. Él ha jugado un papel muy significante en el inicio de mi vida académica. Sus ideas y su entusiasmo siempre me inspiraron y me motivaron. Sin su paciencia y su ayuda, nunca hubiera acabado esta tesis. ResumenEn los últimos años, y asociado al desarrollo de la tecnología MEMS, la técnica de indentación instrumentada se ha convertido en un método de ensayo no destructivo ampliamente utilizado para hallar las características elástico-plásticas de recubrimientos y capas delgadas, desde la escala macroscópica a la microscópica. Sin embargo, debido al complejo mecanismo de contacto debajo de la indentación, es urgente proponer un método más simple y conveniente para obtener unos resultados comparables con otras mediciones tradicionales. En este estudio, el objetivo es mejorar el procedimiento analítico para extraer las propiedades elástico-plásticas del material mediante la técnica de indentación instrumentada.La primera parte se centra en la metodología llevada a cabo para medir las propiedades elásticas de los materiales elásticos, presentándose una nueva metodología de indentación, basada en la evolución de la rigidez de contacto y en la curva fuerza-desplazamiento del ensayo de indentación. El método propuesto permite discriminar los valores de indentación experimental que pudieran estar afectados por el redondeo de la punta del indentador. Además, esta técnica parece ser robusta y permite obtener valores fiables del modulo elástico.La segunda parte se centra en el proceso analítico para determinar la curva tensión-deformación a partir del ensayo de indentación, empleando un indentador esférico. Para poder asemejar la curva tension-deformación de indentación con la que se obtendría de un ensayo de tracción, Tabor determinó empíricamente un factor de constricción de la tensión () y un factor de constricción de la deformación (). Sin embargo, la elección del valor de  y  necesitan una derivación analítica. Se describió analíticamente una nueva visión de la relación entre los factores de constricción de tensión y la deformación basado en la deducción de la viii ecuación de Tabor. Un modelo de elementos finitos y un diseño experimental se realizan para evaluar estos factores de constricción. A partir de los resultados obtenidos, las curvas tension-deformación extraidas de los ensayos de indentación esférica, afectadas por los correspondientes factores de constricción de tension y deformación, se ajustaron a la curva nominal tensión-deformación obtenida de ensayos de tracción convencionales.En la última parte, se estudian las propiedades del revestimiento de cermet Inconel 625-Cr 3 C 2 que es depositado en el medio de una a...

show abstract

Analytical relations between hardness and strain for cold formed parts

Cited by 107 publications

References 53 publications

Finite Element Analysis of Surface Integrity in Deep Ball-Burnishing of a Biodegradable AZ31B Mg Alloy

Finite Element Analysis of Surface Integrity in Deep Ball-Burnishing of a Biodegradable AZ31B Mg Alloy

Investigation of the Influence of Tool Geometry on Effective Strain Distribution in Full Forward Extrusion

Determining the elastic-plastic properties of metallic materials through instrumented indentation

Contact Info

Product

Resources

About