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14 pages, 11167 KiB

Open AccessArticle

Effect of Temperature and Strain on Bonding of Similar AA3105 Aluminum Alloys by the Roll Bonding Process

by Mauro Carta, Pasquale Buonadonna, Barbara Reggiani, Lorenzo Donati, Francesco Aymerich and Mohamad El Mehtedi

Metals 2024, 14(8), 920; https://doi.org/10.3390/met14080920 - 14 Aug 2024

Viewed by 423

Abstract

Accumulative roll bonding (ARB) is a severe plastic deformation process that enables the production of materials with ultrafine microstructures and enhances the characteristics of the base material, particularly in metal matrix composites. The primary objective of this study is to experimentally investigate the [...] Read more.

Accumulative roll bonding (ARB) is a severe plastic deformation process that enables the production of materials with ultrafine microstructures and enhances the characteristics of the base material, particularly in metal matrix composites. The primary objective of this study is to experimentally investigate the bonding strength in AA3105 strips that underwent the roll bonding process, with a specific focus on examining the influence of temperature and reduction rate on bonding. Three temperature levels (200 °C, 300 °C, and 400 °C) and three thickness reduction levels (35%, 50%, and 65%) were considered. The T-peel test was carried out to assess the bonding quality. It was employed to determine the peak force required to separate the two bonded strips. Additionally, ANOVA analysis was performed to develop a regression equation for analyzing peak force. Optical microscopy was used to evaluate the interface bonding quality in the longitudinal section. The results indicate that the bonding strength increases with both temperature and percentage reduction. Full article

(This article belongs to the Special Issue Metal Rolling and Heat Treatment Processing)

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13 pages, 2957 KiB

Open AccessArticle

Effect of Annealing Temperature on Microstructure and Properties of DH Steel and Optimization of Hole Expansion Property

by Yuhuan Yang, Xiaoyue Ma, Hongzhou Lu and Zhengzhi Zhao

Metals 2024, 14(7), 791; https://doi.org/10.3390/met14070791 - 7 Jul 2024

Viewed by 754

Abstract

In this article, DH steel containing Nb and Nb-Cu above 1000 MPa was designed, and its phase transformation law was analyzed through thermal expansion tests. The influence of annealing temperature on the microstructure and properties of DH steel was studied using a continuous [...] Read more.

In this article, DH steel containing Nb and Nb-Cu above 1000 MPa was designed, and its phase transformation law was analyzed through thermal expansion tests. The influence of annealing temperature on the microstructure and properties of DH steel was studied using a continuous annealing simulation testing machine, SEM, and tensile testing machine. The results showed that under a continuous annealing process, the test steel is composed of ferrite, martensite, a small amount of bainite, and residual austenite. The tensile strength decreases with the increase in annealing temperature, Cu element is dissolved in the matrix which produces solid solution strengthening and results in an increase in the strength of Cu-bearing test steel. Finally, 1180 MPa grade DH steel with excellent comprehensive properties was obtained at an annealing temperature of 840 °C and an overaging temperature of 340 °C. The expansion performance of the experimental steel was studied and optimized. Under the step heating annealing process, the experimental steel is composed of tempered martensite, ferrite, and residual austenite, with smaller differences in hardness between different phases, lower average dislocation density, and better expansion performance. Cu-bearing DH steel achieved an excellent match of strength and plasticity of 1289 MPa × 19.8%, with the hole expansion rate of 21.9% and the loss rate of hole expansion rate of 10%. Full article

(This article belongs to the Special Issue Metal Rolling and Heat Treatment Processing)

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28 pages, 20125 KiB

Open AccessArticle

Multi Response Modelling and Optimisation of Copper Content and Heat Treatment Parameters of ADI Alloys by Combined Regression Grey-Fuzzy Approach

by Nikša Čatipović, Ivan Peko, Karla Grgić and Karla Periša

Metals 2024, 14(6), 735; https://doi.org/10.3390/met14060735 - 20 Jun 2024

Viewed by 706

Abstract

This paper deals with the austempering of ductile iron (ADI) and clarifies the influential austempering parameters during the production of ADI. During the austempering process, the heat treatment parameters can be varied, thus influencing the final microstructure and, of course, the mechanical properties [...] Read more.

This paper deals with the austempering of ductile iron (ADI) and clarifies the influential austempering parameters during the production of ADI. During the austempering process, the heat treatment parameters can be varied, thus influencing the final microstructure and, of course, the mechanical properties of ADI. To appropriately conduct experiments and obtain good results, an experimental plan was developed using the Design Expert 13 software. Along with the heat treatment parameters, the influence of the copper content on the ADI toughness, tensile strength, and elongation was determined. The obtained results from this experiment were used to develop unique mathematical models which describe the influences of heat treatment and copper content on the observed mechanical properties of ADI samples. These mathematical models can be applied to predict the analysed mechanical properties of ADI in the dependence of heat treatment parameters and copper content in base ductile iron. For the multi response optimisation of toughness, tensile strength, and elongation, a hybrid grey-fuzzy technique was presented as a significant contribution to the enhancement of the analysed mechanical properties. Consequently, the copper content and heat treatment parameter levels that resulted in the maximal mechanical properties’ functions were defined. Full article

(This article belongs to the Special Issue Metal Rolling and Heat Treatment Processing)

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15 pages, 4753 KiB

Open AccessArticle

Numerical Study on the Heat Transfer of Confined Air-Jet Quenching of Steel Sheets

by Yanqi Ye, Tianliang Fu, Guanghao Liu and Guodong Wang

Metals 2024, 14(4), 377; https://doi.org/10.3390/met14040377 - 24 Mar 2024

Viewed by 980

Abstract

The high flatness quenching of ultra-high-strength steel sheets is a technical problem in the steel industry. In this study, the traditional water and spray quenching methods were abandoned, and the roller-constrained slot air-jet quenching method was proposed for steel sheets below 3 mm [...] Read more.

The high flatness quenching of ultra-high-strength steel sheets is a technical problem in the steel industry. In this study, the traditional water and spray quenching methods were abandoned, and the roller-constrained slot air-jet quenching method was proposed for steel sheets below 3 mm thickness, which provided a theoretical reference for producing thinner, wider, and higher-flatness steel sheets. A 2D roller-constrained slot air-jet numerical model was established to study the flow field and heat transfer characteristics under the conditions of Reynolds number 24,644–41,076, a dimensionless jet height of 16–24, and a jet angle of 45°–135°. The results showed that the average Nusselt number on the heat transfer surface was proportional to Re^m. At the same time, high-intensity heat transfer was achieved when the dimensionless height and jet angle were properly combined. At the same Reynolds number, the heat transfer intensity could be increased by 289%. In addition, the position of the peak Nusselt number was affected by reducing the jet angle, which served as an effective strategy for adjusting the martensite ratio and obtaining ideal mechanical properties. Full article

(This article belongs to the Special Issue Metal Rolling and Heat Treatment Processing)

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22 pages, 7668 KiB

Open AccessArticle

Digital Model of Plan View Pattern Control for Plate Mills Based on Machine Vision and the DBO-RBF Algorithm

by Zhijie Jiao, Shiwen Gao, Chujie Liu, Junyi Luo, Zhiqiang Wang, Guanyu Lang, Zhong Zhao, Zhiqiang Wu and Chunyu He

Metals 2024, 14(1), 94; https://doi.org/10.3390/met14010094 - 12 Jan 2024

Cited by 2 | Viewed by 1244

Abstract

Plan view pattern control (PVPC) is a highly effective means to improve the rectangularization of products and increase the yield of plate mills. By optimizing the parameters of PVPC, the effect of PVPC can be further improved. In this paper, a digital model [...] Read more.

Plan view pattern control (PVPC) is a highly effective means to improve the rectangularization of products and increase the yield of plate mills. By optimizing the parameters of PVPC, the effect of PVPC can be further improved. In this paper, a digital model for predicting and controlling crop patterns of plates is proposed based on the radial basis function (RBF) neural network optimized by the dung beetle optimizer (DBO) algorithm. Machine vision technology is used to obtain a digital description of the crop pattern of the rolled plates. An automatic threshold adjustment algorithm is proposed for the image processing of plate pattern photos during the rolling process. The error between the pattern data calculated through machine vision technology and the measured pattern data does not exceed 3 mm. The spread parameters of the RBF are optimized using DBO, and the digital model structure is established. The goodness of fit (R²) and the mean absolute error (MAE) are used as evaluation indicators. The results show that the digital model established based on DBO-RBF has good predictive and control performance, realizing intelligent prediction of the crop pattern of plates and the parameter optimization of PVPC. In practical applications, the crop cutting loss area of irregular deformation at the end of the plate can be reduced by 31%. Full article

(This article belongs to the Special Issue Metal Rolling and Heat Treatment Processing)

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13 pages, 7205 KiB

Open AccessArticle

Effects of Finish Rolling Temperature on the Critical Crack Tip Opening Displacement (CTOD) of Typical 500 MPa Grade Weathering Steel

by Junping Wu, Guangming Bai, Liyang Zhao, Zhongde Zhang, Yan Peng, Juefei Chu and Qingfeng Wang

Metals 2023, 13(10), 1791; https://doi.org/10.3390/met13101791 - 23 Oct 2023

Cited by 1 | Viewed by 1158

Abstract

In this study, the effect of finish rolling temperature on the critical crack tip opening displacement (CTOD) of typical 500 MPa grade weathering steel was elucidated. The microstructures were observed via optical microscope (OM), scanning electron microscope (SEM), transmission electron microscope (TEM), and [...] Read more.

In this study, the effect of finish rolling temperature on the critical crack tip opening displacement (CTOD) of typical 500 MPa grade weathering steel was elucidated. The microstructures were observed via optical microscope (OM), scanning electron microscope (SEM), transmission electron microscope (TEM), and electron back-scattered diffraction (EBSD). The cryogenic fracture toughness and microstructures of steels were analyzed at different finish rolling temperatures (780–840 °C). The results show that a mixed microstructure, i.e., granular bainitic ferrite (GBF), polygonal ferrite (PF), and martensite/austenite (M/A), constituent was formed in each sample. With the decrease of the finish rolling temperature, the GBF content decreased, PF content increased, and the high angle grain boundary (HAGB) number fraction of the matrix increased. Furthermore, the fraction of M/A constituents was increased with reduced average size. The value of CTOD increased significantly from 0.28 to 1.12 mm as the finish rolling temperature decreased from 840 to 780 °C. Both the decrease of M/A constituents and the increase of HAGB increased the cryogenic (−40 °C) fracture toughness of the typical 500 MPa grade weathering steel. Full article

(This article belongs to the Special Issue Metal Rolling and Heat Treatment Processing)

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14 pages, 12260 KiB

Open AccessFeature PaperArticle

Achieving High Plasticity and High Toughness of Low-Carbon Low-Alloy Steel through Intercritical Heat Treatment

by Long Huang, Jia Liu, Xiangtao Deng and Zhaodong Wang

Metals 2023, 13(10), 1737; https://doi.org/10.3390/met13101737 - 13 Oct 2023

Cited by 1 | Viewed by 1376

Abstract

Medium manganese steel has excellent comprehensive properties due to the TRIP effect of retained austenite, but its welding performance is unsatisfactory for its high alloy content. This study obtained retained austenite in low-carbon low-alloy steel with low contents of silicon and manganese elements [...] Read more.

Medium manganese steel has excellent comprehensive properties due to the TRIP effect of retained austenite, but its welding performance is unsatisfactory for its high alloy content. This study obtained retained austenite in low-carbon low-alloy steel with low contents of silicon and manganese elements through intercritical heat treatment. The influence of intercritical quenching temperature on the content and characteristics of the retained austenite, as well as the functional mechanism of the retained austenite during low-temperature impact, was studied. The results showed that the content of the retained austenite increased from 12% to 17%, and its distribution extended from grain boundaries to martensite lath boundaries, with increasing intercritical quenching temperature. The retained austenite on the grain boundaries was in blocks, and that on the martensitic lath boundaries formed slender domains. The stability of the retained austenite was achieved through the enrichment of C and Mn during intercritical heat treatment. The contribution of retained austenite to low-temperature mechanical properties was closely related to its stability. The retained austenite with poor stability underwent martensite transformation at low temperatures, and the high-carbon martensite was a brittle phase that became the nucleation site of cracks or the path of crack growth during impact. Stable retained austenite passivated crack tips and hindered crack propagation during impacts, which improved the impact performance of the steel. Full article

(This article belongs to the Special Issue Metal Rolling and Heat Treatment Processing)

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13 pages, 6463 KiB

Open AccessArticle

Influence of 0.5% Ag Addition on Low-Cycle Fatigue Behavior of Hot-Extruded Al-5Cu-0.8Mg-0.15Zr-0.2Sc Alloy Subjected to Peak-Aging Treatment

by Ying Wang, Lijia Chen, Ge Zhou, Ruochong Liu and Siqian Zhang

Metals 2023, 13(10), 1734; https://doi.org/10.3390/met13101734 - 12 Oct 2023

Viewed by 823

Abstract

The total strain amplitude controlled low-cycle fatigue tests were performed at room temperature and 200 °C to clarify the influence of 0.5% Ag addition on the low-cycle fatigue behavior of an Al-5Cu-0.8Mg-0.15Zr-0.2Sc (in wt.%) alloy subjected to the peak-aging treatment after hot extrusion [...] Read more.

The total strain amplitude controlled low-cycle fatigue tests were performed at room temperature and 200 °C to clarify the influence of 0.5% Ag addition on the low-cycle fatigue behavior of an Al-5Cu-0.8Mg-0.15Zr-0.2Sc (in wt.%) alloy subjected to the peak-aging treatment after hot extrusion and solid solution treatment. The experimental results demonstrate that during low-cycle fatigue deformation, peak-aged Al-5Cu-0.8Mg-0.15Zr-0.2Sc(-0.5Ag) alloys exhibit cyclic hardening, cyclic stability, or cyclic hardening followed by cyclic stability, depending on the Ag addition, imposed total strain amplitude, and testing temperature. The addition of 0.5% Ag greatly increases the low-cycle fatigue life of peak-aged Al-5Cu-0.8Mg-0.15Zr-0.2Sc alloy, where the maximum rising amplitude is about 126.7% at ambient temperature and approximately 90.1% at 200 °C. Furthermore, it has been discovered that the addition of 0.5% Ag has no effect on the beginning and spreading modes of low-cycle fatigue fractures. For the peak-aged Al-5Cu-0.8Mg-0.15Zr-0.2Sc(-0.5Ag) alloys subjected to low-cycle fatigue deformation at different total strain amplitudes and testing temperatures used in this investigation, fatigue cracks initiate trans granularly at the free surface of the fatigue specimen and propagate in a trans granular mode. Full article

(This article belongs to the Special Issue Metal Rolling and Heat Treatment Processing)

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17 pages, 9711 KiB

Open AccessArticle

Effect of Heat Input on Microstructure and Tensile Properties in Simulated CGHAZ of a V-Ti-N Microalloyed Weathering Steel

by Bing Hu, Qiuming Wang and Qingfeng Wang

Metals 2023, 13(9), 1607; https://doi.org/10.3390/met13091607 - 17 Sep 2023

Cited by 2 | Viewed by 1348

Abstract

The mechanical properties of a coarse-grained heat-affected zone (CGHAZ) are affected by welding thermal cycling with varied heat input (E_j), but its effect on tensile properties is rarely studied. In the present work, E_j = 15, 35, 55, 75 [...] Read more.

The mechanical properties of a coarse-grained heat-affected zone (CGHAZ) are affected by welding thermal cycling with varied heat input (E_j), but its effect on tensile properties is rarely studied. In the present work, E_j = 15, 35, 55, 75 kJ/cm CGHAZ samples were prepared via Gleeble^TM (St. Paul, MN, USA) for a novel V-Ti-N microalloyed weathering steel. The tensile properties of CGHAZ with varied E_j were evaluated. The results indicated that mixed microstructures dominated by lath bainitic ferrite (LBF) and granular bainitic ferrite (GBF) were obtained at E_j = 15 and 35 kJ/cm, respectively, while a mixed microstructure composed of GBF, intragranular acicular ferrite (IGAF), and polygon ferrite (PF) formed at E_j = 55 and 75 kJ/cm, apart from martensite/austenite (M/A) constituents in each E_j condition. The above variation tendency in the microstructure with the increase in E_j led to coarsening of low-angle grain boundaries (LAGBs) and a decrease in dislocation density, which in turn resulted in a yield strength (YS) decrease from 480 MPa to 416 MPa. The mean equivalent diameter (MED), defined by the misorientation tolerance angles (MTAs) ranging from 2–6°, had the strongest contribution to YS due to their higher fitting coefficient of the Hall–Petch relationship. In addition, the increase in the average size (d_M/A) of M/A constituents from 0.98 μm to 1.81 μm and in their area fraction (f_M/A) from 3.11% to 4.42% enhanced the strain-hardening stress. The yield strength ratio (YR) reduced as the E_j increased, and the lower density and more uniform dislocations inside the ferrite led to a uniform elongation (uE) increase from 9.5% to 18.6%. Full article

(This article belongs to the Special Issue Metal Rolling and Heat Treatment Processing)

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