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T.c Lee - One of the best experts on this subject based on the ideXlab platform.
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Formability and Weld Zone Analysis of Tailor-Welded Blanks for Various Thickness Ratios
Journal of Engineering Materials and Technology, 2005Co-Authors: Luen Chow Chan, S.m Chan, C. H. Cheng, T.c LeeAbstract:Cold-rolled steel sheets of thicknesses ranging from 0.5 to 1.0 mm were used to produce tailor-welded blanks (TWBs) with various thickness ratios. In this study, the formability of the TWBs, as well as the mechanical characteristics of the weld zones, were analyzed experimentally under the effects of various thickness ratios of TWBs. The formability of the TWBs was evaluated in terms of three measures-failure mode, forming limit diagram, and minimum Major Strain, whereas the mechanical characteristics of the weld zones were investigated by tensile testing, metallographic study, and microhardness measurement. In particular, circular TWBs with different radii and cutoff widths were designed where all the welds were located in the center of the blanks and perpendicular to the principal Strain direction. Nd:YAG laser butt-welding was used to weld the TWB specimens of different thickness ratios. The experimental findings in this study showed that the higher the thickness ratio of the TWBs, the lower the forming limit curve level, and the lower formability. The minimum Major Strain was clearly inversely proportional to the thickness ratio of the TWBs. On the other hand, the results of uniaxial tensile tests clearly illustrated that there was no significant difference between the tensile strengths of the TWBs and those of the base metals. The metallographic study demonstrated a difference of grain size in the materials at base metal, heat-affected zones, and fusion zone. The microhardness measurement indicated that the hardness in the fusion zone increased by about 60% of the base metal.
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Formability Analysis of Tailor-Welded Blanks of Different Thickness Ratios
Journal of Manufacturing Science and Engineering, 2005Co-Authors: Luen Chow Chan, S.m Chan, T.c Lee, C. H. Cheng, C. L. ChowAbstract:This paper presents a formability analysis of tailor-welded blanks (TWBs) made of cold rolled steel sheets with varying thicknesses. Steel sheets ranging between 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, and 1.0 mm in thickness were used to produce TWBs of different thickness combinations. The primary objective of this paper is to characterize the effects of thickness ratios on the forming limit diagram (FLD) for a particular type of TWB. The TWBs chosen for the investigation are designed with the weld line located in the center of the specimens perpendicular to the principal Strain direction. Nd:YAG laser butt-welding was used to prepare different tailor-made blank specimens for uniaxial tensile tests and Swift tests. The experimental results of the uniaxial tensile test clearly revealed that there were no significant differences between the tensile strengths of TWBs and those of the base metals. After the Swift tests, the formability of TWBs was analyzed in terms of two measures: The forming limit diagram and minimum Major Strain. The experimental findings indicated that the higher the thickness ratio, the lower the level of the forming limit curve (FLC) and the lower the formability of the TWBs. The findings also show an inverse proportional relationship between thickness ratios and minimum Major Strains. TWBs with a thickness ratio of close to 1 were found to have a minimum Major Strain closer to those of base metals. The effects of different thickness ratios on TWBs were further analyzed with a finite element code in a computer-aided engineering package, PAM-STAMP, while the failure criteria of the TWBs in the finite element analysis were addressed by the FLCs which were obtained from the experiments. However, the weld of the TWB in the simulation was simply treated as a thickness step, whereas its heat affected zones were sometimes disregarded, so that the effects of the thickness ratio could be significantly disclosed without the presence of weld zones. The results of the simulation should certainly assist to clarify and explain the effects of different thickness ratios on TWBs.
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Tailor-welded blanks of different thickness ratios effects on forming limit diagrams
Journal of Materials Processing Technology, 2003Co-Authors: S.m Chan, L.c Chan, T.c LeeAbstract:In this paper, the objective is to study the thickness ratio effects of TWBs on forming limit diagrams (FLDs). Tailor-welded blanks (TWBs) of the same material but with different thickness combinations were welded together to form a single part before the formability tests. Thus, SPCC steel sheets of thickness 0.5, 0.6, 0.8 and 1.0 mm were studied and combined to form TWBs of different thickness ratios of 2 (0.5/1.0 mm), 1.67 (0.6/1.0 mm) and 1.25 (0.8/1.0 mm). An Nd:YAG laser was used to weld the tailor-made blanks before the formability tests of the uniaxial tensile test and the Swift test. The experimental findings show that TWBs of different dimensions and radii of cut-off yield different Major Strain and minor Strain values of the FLD. The uniaxial tensile tests show that there are no significant differences between the tensile strengths of TWBs and their relative base metals. In addition, the FLDs of the TWBs indicate that both the level of the forming limit curves and the minimum Major Strain value decreases as the thickness ratio increases. This implies that the higher is the thickness ratio, the lower is the formability of the TWBs.Department of Industrial and Systems Engineerin
Ramazanali Mahdavinejad - One of the best experts on this subject based on the ideXlab platform.
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A Novel Approach to the Determination of Forming Limit Diagrams for Tailor-Welded Blanks
Journal of Materials Engineering and Performance, 2013Co-Authors: Hossein Mamusi, Abolfazl Masoumi, Ramin Hashemi, Ramazanali MahdavinejadAbstract:This paper presents the results of simulated hemispherical die stretching of laser-welded, low carbon steel (ST12 and ST14) blanks of various thicknesses. The simulations were designed to produce forming limit diagrams (FLDs) for the tailor-welded blanks. Multiple criteria, including the second time derivatives of Major Strain, thickness Strain, and equivalent plastic Strain extracted from the Strain history of simulations, were used to accurately detect the start of necking in FLDs. This is to say that necking starts when the second derivative of the thickness Strain, Major Strain or plastic Strain reaches its maximum value. Knowing the onset of necking, one can measure the Major and minor Strains at the critical area and produce the corresponding FLD. Results from the proposed method and those from experimental tests are compared to demonstrate the efficiency of the proposed method.
S.m Chan - One of the best experts on this subject based on the ideXlab platform.
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Formability and Weld Zone Analysis of Tailor-Welded Blanks for Various Thickness Ratios
Journal of Engineering Materials and Technology, 2005Co-Authors: Luen Chow Chan, S.m Chan, C. H. Cheng, T.c LeeAbstract:Cold-rolled steel sheets of thicknesses ranging from 0.5 to 1.0 mm were used to produce tailor-welded blanks (TWBs) with various thickness ratios. In this study, the formability of the TWBs, as well as the mechanical characteristics of the weld zones, were analyzed experimentally under the effects of various thickness ratios of TWBs. The formability of the TWBs was evaluated in terms of three measures-failure mode, forming limit diagram, and minimum Major Strain, whereas the mechanical characteristics of the weld zones were investigated by tensile testing, metallographic study, and microhardness measurement. In particular, circular TWBs with different radii and cutoff widths were designed where all the welds were located in the center of the blanks and perpendicular to the principal Strain direction. Nd:YAG laser butt-welding was used to weld the TWB specimens of different thickness ratios. The experimental findings in this study showed that the higher the thickness ratio of the TWBs, the lower the forming limit curve level, and the lower formability. The minimum Major Strain was clearly inversely proportional to the thickness ratio of the TWBs. On the other hand, the results of uniaxial tensile tests clearly illustrated that there was no significant difference between the tensile strengths of the TWBs and those of the base metals. The metallographic study demonstrated a difference of grain size in the materials at base metal, heat-affected zones, and fusion zone. The microhardness measurement indicated that the hardness in the fusion zone increased by about 60% of the base metal.
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Formability Analysis of Tailor-Welded Blanks of Different Thickness Ratios
Journal of Manufacturing Science and Engineering, 2005Co-Authors: Luen Chow Chan, S.m Chan, T.c Lee, C. H. Cheng, C. L. ChowAbstract:This paper presents a formability analysis of tailor-welded blanks (TWBs) made of cold rolled steel sheets with varying thicknesses. Steel sheets ranging between 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, and 1.0 mm in thickness were used to produce TWBs of different thickness combinations. The primary objective of this paper is to characterize the effects of thickness ratios on the forming limit diagram (FLD) for a particular type of TWB. The TWBs chosen for the investigation are designed with the weld line located in the center of the specimens perpendicular to the principal Strain direction. Nd:YAG laser butt-welding was used to prepare different tailor-made blank specimens for uniaxial tensile tests and Swift tests. The experimental results of the uniaxial tensile test clearly revealed that there were no significant differences between the tensile strengths of TWBs and those of the base metals. After the Swift tests, the formability of TWBs was analyzed in terms of two measures: The forming limit diagram and minimum Major Strain. The experimental findings indicated that the higher the thickness ratio, the lower the level of the forming limit curve (FLC) and the lower the formability of the TWBs. The findings also show an inverse proportional relationship between thickness ratios and minimum Major Strains. TWBs with a thickness ratio of close to 1 were found to have a minimum Major Strain closer to those of base metals. The effects of different thickness ratios on TWBs were further analyzed with a finite element code in a computer-aided engineering package, PAM-STAMP, while the failure criteria of the TWBs in the finite element analysis were addressed by the FLCs which were obtained from the experiments. However, the weld of the TWB in the simulation was simply treated as a thickness step, whereas its heat affected zones were sometimes disregarded, so that the effects of the thickness ratio could be significantly disclosed without the presence of weld zones. The results of the simulation should certainly assist to clarify and explain the effects of different thickness ratios on TWBs.
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Tailor-welded blanks of different thickness ratios effects on forming limit diagrams
Journal of Materials Processing Technology, 2003Co-Authors: S.m Chan, L.c Chan, T.c LeeAbstract:In this paper, the objective is to study the thickness ratio effects of TWBs on forming limit diagrams (FLDs). Tailor-welded blanks (TWBs) of the same material but with different thickness combinations were welded together to form a single part before the formability tests. Thus, SPCC steel sheets of thickness 0.5, 0.6, 0.8 and 1.0 mm were studied and combined to form TWBs of different thickness ratios of 2 (0.5/1.0 mm), 1.67 (0.6/1.0 mm) and 1.25 (0.8/1.0 mm). An Nd:YAG laser was used to weld the tailor-made blanks before the formability tests of the uniaxial tensile test and the Swift test. The experimental findings show that TWBs of different dimensions and radii of cut-off yield different Major Strain and minor Strain values of the FLD. The uniaxial tensile tests show that there are no significant differences between the tensile strengths of TWBs and their relative base metals. In addition, the FLDs of the TWBs indicate that both the level of the forming limit curves and the minimum Major Strain value decreases as the thickness ratio increases. This implies that the higher is the thickness ratio, the lower is the formability of the TWBs.Department of Industrial and Systems Engineerin
Gholamhosein Liaghat - One of the best experts on this subject based on the ideXlab platform.
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forming limit diagram prediction of tailor welded blank using experimental and numerical methods
Journal of Materials Engineering and Performance, 2012Co-Authors: Rasoul Safdarian Korouyeh, Hassan Moslemi Naeini, Gholamhosein LiaghatAbstract:The forming limit diagram (FLD) is a useful method for characterizing the formability of sheet metals. In this article, different numerical models were used to investigate the FLD of tailor-welded blank (TWB). TWBs were CO2 laser-welded samples of interstitial-free (IF) steel sheets with difference in thickness. The results of the numerical models were compared with the experimental FLD as well as with the empirical model proposed by the North American Deep Drawing Research Group. The emphasis of this investigation is to determine the performance of these different approaches in predicting the FLD. These numerical models for FLD are: second derivative of thinning (SDT), effective Strain rate (ESR), Major Strain rate (MSR), thickness Strain rate (TSR), and thickness gradient (TG). Results of this research show necking will be happened, when the value of MSR, TSR, ESR criteria is maximum, TG ≤ 0.78 and SDT criterion has the first peak in forming process time. The value of dome height of TWB samples at failure was predicted based on the numerical models for samples with different widths. These numerical predictions were compared with the experimental results. The SDT model indicates a better agreement with experimental results in prediction of both the FLD and the limit dome height (LDH) in comparison to the other numerical models. Both numerical and experimental results show that minimum of LDH is happened in plane Strain condition.
Luen Chow Chan - One of the best experts on this subject based on the ideXlab platform.
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Experimental Study on the Relationship between Hardness and Principal Strain in Tube Hydroforming Process
2009Co-Authors: G D Wang, Luen Chow ChanAbstract:In order to find a feasible method to evaluate the deformation of tubes during the Tube Hydroforming (THF) process, the hardness and the Strain in two selected deformation areas of hydro formed copper tubes (C11000) were measured and tested, and an instinct relationship was found between the hardness and the principal Strains of the tubes. The Major Strain of the surface of tubes had the strongest linear relationship with hardness. A regression formula was used to describe the relationship between hardness and the sensitive Strain which is defined in the present work as a dependent variable of Major Strain and thickness Strain.
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Formability and Weld Zone Analysis of Tailor-Welded Blanks for Various Thickness Ratios
Journal of Engineering Materials and Technology, 2005Co-Authors: Luen Chow Chan, S.m Chan, C. H. Cheng, T.c LeeAbstract:Cold-rolled steel sheets of thicknesses ranging from 0.5 to 1.0 mm were used to produce tailor-welded blanks (TWBs) with various thickness ratios. In this study, the formability of the TWBs, as well as the mechanical characteristics of the weld zones, were analyzed experimentally under the effects of various thickness ratios of TWBs. The formability of the TWBs was evaluated in terms of three measures-failure mode, forming limit diagram, and minimum Major Strain, whereas the mechanical characteristics of the weld zones were investigated by tensile testing, metallographic study, and microhardness measurement. In particular, circular TWBs with different radii and cutoff widths were designed where all the welds were located in the center of the blanks and perpendicular to the principal Strain direction. Nd:YAG laser butt-welding was used to weld the TWB specimens of different thickness ratios. The experimental findings in this study showed that the higher the thickness ratio of the TWBs, the lower the forming limit curve level, and the lower formability. The minimum Major Strain was clearly inversely proportional to the thickness ratio of the TWBs. On the other hand, the results of uniaxial tensile tests clearly illustrated that there was no significant difference between the tensile strengths of the TWBs and those of the base metals. The metallographic study demonstrated a difference of grain size in the materials at base metal, heat-affected zones, and fusion zone. The microhardness measurement indicated that the hardness in the fusion zone increased by about 60% of the base metal.
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Formability Analysis of Tailor-Welded Blanks of Different Thickness Ratios
Journal of Manufacturing Science and Engineering, 2005Co-Authors: Luen Chow Chan, S.m Chan, T.c Lee, C. H. Cheng, C. L. ChowAbstract:This paper presents a formability analysis of tailor-welded blanks (TWBs) made of cold rolled steel sheets with varying thicknesses. Steel sheets ranging between 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, and 1.0 mm in thickness were used to produce TWBs of different thickness combinations. The primary objective of this paper is to characterize the effects of thickness ratios on the forming limit diagram (FLD) for a particular type of TWB. The TWBs chosen for the investigation are designed with the weld line located in the center of the specimens perpendicular to the principal Strain direction. Nd:YAG laser butt-welding was used to prepare different tailor-made blank specimens for uniaxial tensile tests and Swift tests. The experimental results of the uniaxial tensile test clearly revealed that there were no significant differences between the tensile strengths of TWBs and those of the base metals. After the Swift tests, the formability of TWBs was analyzed in terms of two measures: The forming limit diagram and minimum Major Strain. The experimental findings indicated that the higher the thickness ratio, the lower the level of the forming limit curve (FLC) and the lower the formability of the TWBs. The findings also show an inverse proportional relationship between thickness ratios and minimum Major Strains. TWBs with a thickness ratio of close to 1 were found to have a minimum Major Strain closer to those of base metals. The effects of different thickness ratios on TWBs were further analyzed with a finite element code in a computer-aided engineering package, PAM-STAMP, while the failure criteria of the TWBs in the finite element analysis were addressed by the FLCs which were obtained from the experiments. However, the weld of the TWB in the simulation was simply treated as a thickness step, whereas its heat affected zones were sometimes disregarded, so that the effects of the thickness ratio could be significantly disclosed without the presence of weld zones. The results of the simulation should certainly assist to clarify and explain the effects of different thickness ratios on TWBs.
