Metals

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15 pages, 6653 KiB

Open AccessArticle

Crystal Plasticity Finite Element Analyses on the Formability of AA6061 Aluminum Alloy with Different Ageing Treatments

by Huai Wang, Ho-Won Lee, Seong-Hoon Kang and Dong-Kyu Kim

Metals 2024, 14(5), 503; https://doi.org/10.3390/met14050503 - 26 Apr 2024

Viewed by 379

Different ageing treatments have been developed to achieve targeted properties in aluminum alloys through altering microstructures. However, there is a lack of understanding regarding the effect of ageing treatments on the formability of these alloys. In this study, we employed crystal plasticity finite [...] Read more.

Different ageing treatments have been developed to achieve targeted properties in aluminum alloys through altering microstructures. However, there is a lack of understanding regarding the effect of ageing treatments on the formability of these alloys. In this study, we employed crystal plasticity finite element (CPFE) modeling, in conjunction with the Marciniak-Kuczynski (M-K) approach, to investigate the effects of ageing treatments on the mechanical properties and formability of AA6061 aluminum alloy. The as-received sheet was in the T6 heat treatment state, which was subjected to artificial ageing and pre-ageing, respectively, to achieve two age-hardened alloys with modified precipitation states. The microstructures and crystallographic textures of the three alloys were measured using the electron backscattering diffraction (EBSD) technique, and uniaxial tensile tests were performed along the rolling direction (RD), transverse direction (TD), and diagonal direction (DD, 45° to the RD) for each alloy. The forming limit curve (FLC) of the as-received alloy was determined using the Nakazima test. The dependence of mechanical strength, tensile ductility, and work-hardening behavior on the ageing treatments was clarified. Then, the tensile test results were utilized to calibrate the modeling parameters used in the CPFE model, whereas the FLC predictability of the developed model was validated with the experimental one. In the formability analysis, the effects of the ageing treatment on the FLC exhibit a notable dependency on loading paths, and the pre-aged alloy exhibits better formability than the other two at the plane strain tension state, thanks to its high work-hardening levels. In addition, the deformed textures along the different loading paths and the effects of the initial texture on the FLC are also discussed. Full article

(This article belongs to the Special Issue Advances in Modeling and Simulation in Metal Forming)

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13 pages, 12763 KiB

Open AccessArticle

Numerical Simulation and Experimental Verification of the Quenching Process for Ti Microalloying H13 Steel Used to Shield Machine Cutter Rings

by Xingwang Feng, Yunxin Wang, Jinxin Han, Zhipeng Li, Likun Jiang and Bin Yang

Metals 2024, 14(3), 313; https://doi.org/10.3390/met14030313 - 07 Mar 2024

Viewed by 696

Abstract

Owing to the non-uniform distribution of chemical composition and temperature during the heat treatment process, the residual stress and deformation of the workpiece emerge as crucial factors requiring consideration in managing the service performance and lifespan of shield machine cutter rings crafted from [...] Read more.

Owing to the non-uniform distribution of chemical composition and temperature during the heat treatment process, the residual stress and deformation of the workpiece emerge as crucial factors requiring consideration in managing the service performance and lifespan of shield machine cutter rings crafted from H13 steel. Considering H13 steel with titanium microalloying as the research object for the shield machine cutter ring, we simulate the quenching process using Deform-3D. The temperature field, phase transformation, stress evolution, and deformation amount after quenching are analyzed. The results demonstrate a strong agreement between the simulation and experimental results, offering valuable insights for optimizing the heat treatment process and enhancing the overall performance of shield machine cutter rings. Full article

(This article belongs to the Special Issue Advances in Modeling and Simulation in Metal Forming)

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20 pages, 17876 KiB

Open AccessArticle

Fatigue Estimation Using Inverse Stamping

by Jaromír Kašpar, Petr Bernardin and Václava Lašová

Metals 2023, 13(12), 1956; https://doi.org/10.3390/met13121956 - 29 Nov 2023

Viewed by 771

Abstract

Reverse engineering methods like 3D scanning are becoming common in engineering practice. These methods enable engineers to reproduce the original shape of a scanned part. If other properties are required, then other reverse engineering methods can follow. Estimation of fatigue is a tricky [...] Read more.

Reverse engineering methods like 3D scanning are becoming common in engineering practice. These methods enable engineers to reproduce the original shape of a scanned part. If other properties are required, then other reverse engineering methods can follow. Estimation of fatigue is a tricky task even if the material properties of the base material are known. Fatigue is influenced not only by material properties and the part’s shape but also by technological processes. Fast fatigue life estimation of stamped parts using reverse engineering methods is the target of this paper. The forming process, which has a crucial impact on the fatigue of stamped parts, is considered via inverse stamping. Adaptation of inverse stamping method from shell FEM meshes to volumetric meshes is included. The article also discusses the application of two methods, the Material Law for Steel Sheets (MLSS) and the Method of Variable Slopes (MVS). These methods adjust the fatigue curve based on effective plastic strain calculated by inverse stamping. Calculated results were compared with experimental results. In most situations, there is a good agreement between the calculations and the tests of the specimens without surface coatings. Sometimes, the calculated results are more conservative than the experiments. This is acceptable in component design in terms of reliability. When a Zn-Ni surface coating was applied, the fatigue life of the specimen decreased. Full article

(This article belongs to the Special Issue Advances in Modeling and Simulation in Metal Forming)

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16 pages, 12482 KiB

Open AccessArticle

Materialization of the Heat-Affected Zone with Laser Tailor-Welded HPF 22MnB5 Steel Using FLD and the Fracture Displacement Method in FE Simulation

by Hyeon Jong Jeon, Chul Kyu Jin, Min Sik Lee, Ok Dong Lim and Nam Su Kang

Metals 2023, 13(10), 1713; https://doi.org/10.3390/met13101713 - 08 Oct 2023

Viewed by 769

Abstract

Using a tailor-welded blank (TWB) and hot-press forming (HPF), a 22MnB5 blank was surface-treated under four conditions. The penetration rates of the Fe_xAl_y compounds under the four surface-treatment conditions were investigated, and the hardness values were measured. A finite element [...] Read more.

Using a tailor-welded blank (TWB) and hot-press forming (HPF), a 22MnB5 blank was surface-treated under four conditions. The penetration rates of the Fe_xAl_y compounds under the four surface-treatment conditions were investigated, and the hardness values were measured. A finite element (FE) simulation was performed for the characteristics of the heat-affected zone (HAZ), using the hardness value and results of previous researchers. In particular, the mechanical property settings of the mesh were designed to realize the conditions for the Fe_xAl_y compounds in the HAZ. Fine meshing was performed by partitioning the HAZ sections. For the mechanical properties of the HAZ with the Fe_xAl_y compounds, the strength was predicted from the hardness value, and the elongation values investigated by other researchers were used. The forming limit diagram, which was proportional to the elongation, was predicted. Specific elements were defined as the areas with Fe_xAl_y compounds, which played the same role as impurities. Tensile TWB–HPF specimens with different HAZ characteristics under four surface-treatment conditions were fabricated. Experiments and FE simulations were performed and compared. Details are as follows: For loads, a minimum error rate of 3% and a maximum error rate of 6% were obtained. For displacement, a minimum error rate of 9% and a maximum error of 25% were obtained. The feasibility of the simulation was verified by comparing the simulation and experimental results. A match of more than 75% was obtained. Full article

(This article belongs to the Special Issue Advances in Modeling and Simulation in Metal Forming)

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18 pages, 5011 KiB

Open AccessArticle

Differential Analysis and Prediction of Planar Shape at the Head and Tail Ends of Medium-Thickness Plate Rolling

by Shiyu Yang, Hongmin Liu and Dongcheng Wang

Metals 2023, 13(6), 1123; https://doi.org/10.3390/met13061123 - 15 Jun 2023

Cited by 1 | Viewed by 856

Abstract

This paper aims to improve planar shape prediction accuracy in the rolling process of medium and thick plates. We present a model based on the strip method that addresses limitations in predicting planar shape variations at the head and tail ends of rolled [...] Read more.

This paper aims to improve planar shape prediction accuracy in the rolling process of medium and thick plates. We present a model based on the strip method that addresses limitations in predicting planar shape variations at the head and tail ends of rolled pieces. By analysing the rolling process, we introduce the concept of an imaginary strip longitudinal length difference to represent planar shape characteristics effectively. By analysing the change in metal shape in the rolling deformation zone, the calculation formula for metal volume in the deformation zone is derived. This establishes a relationship between the longitudinal length difference at the rolled piece ends and the metal volume in the deformation zone. The prediction of plane shape difference between the end and the head of medium and medium-thickness plate is realized. The experimental results confirm the feasibility and effectiveness of the proposed method. Full article

(This article belongs to the Special Issue Advances in Modeling and Simulation in Metal Forming)

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20 pages, 13045 KiB

Open AccessArticle

Influence of Friction Coefficient on the Performance of Cold Forming Tools

by Eneko Barba, Daniel Salcedo, Adrian Claver, Rodrigo Luri and Jose A. Garcia

Metals 2023, 13(5), 960; https://doi.org/10.3390/met13050960 - 15 May 2023

Cited by 1 | Viewed by 1176

Abstract

The automotive industry has undergone significant advancements and changes over time, resulting in the use of more complex parts in modern vehicles. As a consequence, the parts used in the manufacturing process are subject to higher stress levels, which reduce their service life. [...] Read more.

The automotive industry has undergone significant advancements and changes over time, resulting in the use of more complex parts in modern vehicles. As a consequence, the parts used in the manufacturing process are subject to higher stress levels, which reduce their service life. To mitigate this issue, surface treatments can be applied to improve the mechanical properties of the tools. In this study, we examined the impact of surface treatments on reducing tool stress during a cold forming process. The process involved reducing the thickness of a sheet from 6 mm to 2.5 mm, which generated high stresses in the tooling. We used finite element stress calculations to analyze the process and found that by reducing the friction coefficient to 0.1, tool stresses can be reduced by 20%, leading to an increase in tool life. Moreover, the press force and tool wear were also reduced by 18%. To validate the theoretical calculations, we performed field tests in a real manufacturing process. Full article

(This article belongs to the Special Issue Advances in Modeling and Simulation in Metal Forming)

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18 pages, 11275 KiB

Open AccessArticle

Numerical Simulation of Crack Condition in Forging Products of M50 Bearing Steel Based on Processing Map Theory

by Joonhee Park, Byeongchan Han, Hyukjoon Kwon and Naksoo Kim

Metals 2023, 13(5), 921; https://doi.org/10.3390/met13050921 - 09 May 2023

Cited by 2 | Viewed by 1812

Abstract

The microstructure of forged products significantly impacts their properties, and defects or carbide distribution are not visible to the naked eye. Isothermal compression tests on M50 steel with a Gleeble 3500 tester were conducted to study microstructure behavior during forging. Tests examined the [...] Read more.

The microstructure of forged products significantly impacts their properties, and defects or carbide distribution are not visible to the naked eye. Isothermal compression tests on M50 steel with a Gleeble 3500 tester were conducted to study microstructure behavior during forging. Tests examined the hot deformation behavior within a temperature range of 900–1200 °C and a strain rate range of 0.01–10 s⁻¹. Power dissipation efficiency (η) and flow instability (ξ), which are crucial processing map parameters, were employed to analyze the high-temperature deformation behavior of M50 steel. The 3D processing map determined the optimum forging conditions, indicating that hot working should start at an initial temperature of 1050 °C or higher and a strain rate of 1 s⁻¹, decreasing the strain rate and temperature as the strain increases. The 3D power dissipation efficiency map displayed an average value of 0.43 or higher at a strain rate of 0.1 s⁻¹ and a temperature of 1150 °C before reaching a strain rate of 0.8. The Finite Element Method (FEM) simulated results, revealing ξ and η distributions, and confirmed that microstructure observation during deformation matched the hot forging parameters. This approach can effectively predict microstructure changes during hot forging. Full article

(This article belongs to the Special Issue Advances in Modeling and Simulation in Metal Forming)

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20 pages, 15445 KiB

Open AccessArticle

Investigation on the Microstructure and Mechanical Properties of Ni-Based Superalloy with Scandium

by Lin Ye, Feng Liu, Heng Dong, Xiaoqiong Ouyang, Xiangyou Xiao, Liming Tan and Lan Huang

Metals 2023, 13(3), 611; https://doi.org/10.3390/met13030611 - 18 Mar 2023

Viewed by 1463

Abstract

In this work, a method concerning thermal consolidation is proposed to simulate the traditional powder metallurgy process and accomplish the composition screening of powder metallurgy Ni-based superalloys U720Li and RR1000 with rare metal scandium, and superalloys with zero scandium addition, medium scandium addition [...] Read more.

In this work, a method concerning thermal consolidation is proposed to simulate the traditional powder metallurgy process and accomplish the composition screening of powder metallurgy Ni-based superalloys U720Li and RR1000 with rare metal scandium, and superalloys with zero scandium addition, medium scandium addition and high scandium addition are selected. Then effects of scandium on the microstructure and mechanical properties of superalloys are further investigated through fast hot pressed sintering. The results indicate that scandium doping can effectively refine the grain through modifying the size and volume fraction of primary γ’ precipitates at the grain boundary. Meanwhile, scandium can promote the growth and precipitation of secondary γ’ precipitates to some extent. Due to the comprehensive effects of γ’ precipitate modification and grain boundary strengthening, as-sintered U720Li with 0.043 wt.% scandium presents an excellent combination of tensile strength and ductility at ambient and elevated temperature while as-sintered RR1000 with 0.064 wt.% scandium has a good performance at elevated temperature. Full article

(This article belongs to the Special Issue Advances in Modeling and Simulation in Metal Forming)

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19 pages, 6769 KiB

Open AccessArticle

The Effect of the Bridge’s Angle during Porthole Die Extrusion of Aluminum AA6082

by Yu Wang and Mary A. Wells

Metals 2023, 13(3), 605; https://doi.org/10.3390/met13030605 - 16 Mar 2023

Cited by 1 | Viewed by 1369

Abstract

During the porthole die extrusion, the separated metal streams are welded together in the welding chamber. The conditions under which this occurs and the integrity of weld seam in the extrudate are impacted by the design of the bridge, including features such as [...] Read more.

During the porthole die extrusion, the separated metal streams are welded together in the welding chamber. The conditions under which this occurs and the integrity of weld seam in the extrudate are impacted by the design of the bridge, including features such as its shape and dimensions. In this research, the commercial finite element method (FEM) software package, DEFORM, was used to run a series of simulation experiments in order to quantitatively understand the relationship between the bridge design and the thermal mechanical history experienced by the material during welding and the impact this has on final weld seam quality. The bridge can be roughly divided into two parts: the lower part, close to the welding chamber, and the upper part, which initially split the billet into metal streams. The results showed that increasing the lower bridge angle led to slightly higher extrusion loads and higher extrudate exit temperatures. As the lower bridge angle increased, creating a streamlined profile to a blunt profile, a dead metal zone formed under the bridge that produced higher strains near the surface of the material. In contrast, changes to the geometry of the upper bridge had little effect on the porthole die extrusion process or the thermal mechanical conditions experienced by the material. Full article

(This article belongs to the Special Issue Advances in Modeling and Simulation in Metal Forming)

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