Formability of Explosive Welded Mg/Al Bimetallic Bar

2016 ◽  
Vol 716 ◽  
pp. 114-120 ◽  
Author(s):  
Sebastian Mróz ◽  
Piotr Szota ◽  
Teresa Bajor ◽  
Andrzej Stefanik
Keyword(s):  
Plastic Deformation ◽  
Strain Rate ◽  
Process Parameters ◽  
Metal Forming ◽  
Explosive Welding ◽  
Physical Modelling ◽  
Main Process ◽  
Compression Tests ◽  
Welding Method

The paper presents the results of physical modelling of the plastic deformation of the Mg/Al bimetallic specimens using the Gleeble 3800 simulator. The plastic deformation of Mg/Al bimetal specimens characterized by the diameter to thickness ratio equal to 1 was tested in compression tests. The aim of this work was determination of the range of parameters as temperature and strain rate that mainly influence on the plastic deformation of Mg/Al bars during metal forming processes. The tests were carried out for temperature range from 300 to 400°C for different strain rate values. The stock was round 22.5 mm-diameter with an Al layer share of 28% Mg/Al bars that had been produced using the explosive welding method. Based on the analysis of the obtained testing results it has been found that one of the main process parameters influencing the plastic deformation the bimetal components is the initial stock temperature and strain rate values.

A Newly Developed Clamping Device for the Tension/Compression Test at Various Strain Rates

2014 ◽  
Vol 626 ◽  
pp. 353-358
Author(s):  
Geun Su Joo ◽  
Min Kuk Choi ◽  
Hoon Huh
Keyword(s):  
Strain Rate ◽  
Sheet Metal ◽  
Metal Forming ◽  
Loading Condition ◽  
Strain Rates ◽  
Compression Tests ◽  
Compression Behavior ◽  
Compression Loading ◽  
Hardening Behavior ◽  
Clamping Device

The tension/compression hardening behavior is important in sheet metal forming processes because of complicated loading paths. Experimental methods to measure the tension/ compression behavior have not considered the effect of the strain rate although the strain rate is related to the hardening behavior of sheet metal. The tension/compression tests need to be conducted considering the strain rate to acquire accurate hardening behavior.This paper deals with an experimental technique to measure the tension/compression behavior of sheet metal at various strain rates. A new clamping device was developed to prevent a sheet specimen from buckling under compression loading condition. Compared to previous clamping devices, the clamping device was devised to uniformly impose a clamping force and easily measure the strain from side of a specimen. Tension/compression tests have been conducted at various strain rates for SPCC and DP590 with displacement of 10%. Hardening curves under the tension or compression loading condition were obtained and analyzed with respect to the strain rate.

scholarly journals Plastometric tests for plasticine as physical modelling material

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Łukasz Wójcik ◽  
Konrad Lis ◽  
Zbigniew Pater
Keyword(s):  
Strain Rate ◽  
Temperature Change ◽  
Compression Test ◽  
Constitutive Equations ◽  
Metal Forming ◽  
Material Flow ◽  
Physical Modelling ◽  
Flow Curves ◽  
Black And White ◽  
White Colour

Abstract This paper presents results of plastometric tests for plasticine, used as material for physical modelling of metal forming processes. The test was conducted by means of compressing by flat dies of cylindrical billets at various temperatures. The aim of the conducted research was comparison of yield stresses and course of material flow curves. Tests were made for plasticine in black and white colour. On the basis of the obtained experimental results, the influence of forming parameters change on flow curves course was determined. Sensitivity of yield stresses change in function of material deformation, caused by forging temperature change within the scope of 0&C ÷ 20&C and differentiation of strain rate for ˙ɛ = 0.563; ˙ɛ = 0.0563; ˙ɛ = 0.0056s−1,was evaluated. Experimental curves obtained in compression test were described by constitutive equations. On the basis of the obtained results the function which most favourably describes flow curves was chosen.

An Experimental Study on Lubrication Behavior of Glass Lubricants during Hot Plastic Deformation of Ni-Based Alloys

2012 ◽  
Vol 591-593 ◽  
pp. 960-964
Author(s):  
Rui Li ◽  
Chao Yang Sun ◽  
Qing Dong Zhang
Keyword(s):  
Plastic Deformation ◽  
Strain Rate ◽  
Friction Factor ◽  
Flow Behavior ◽  
Compression Tests ◽  
Hot Plastic Deformation ◽  
Ring Compression ◽  
Specimen Material ◽  
Inconel 690 ◽  
Lubrication Performance

Friction factor and flow behavior of melt glass lubricants A5 and up68/2886 during hot plastic deformation of Ni-based alloys Incoloy800H and Inconel 690 were studied by using ring compression tests. The results indicated that glass up68/2886 had higher mobility than glass A5. Friction factor between interfaces went up with temperature in sufficient lubrication, but the opposite in inadequate lubrication, and the friction factor went down with strain rate under both conditions. Besides, yield strength of specimen material also slightly influenced lubrication performance of glass lubricants in inadequate lubrication. Low friction factor about 0.1 was still obtained in inadequate lubrication by using glass up68/2866, therefore excellent performance could be expected when glass up68/2886 was used properly such as at higher strain rate.

Single sample method for assessing the Baushinger effect

2020 ◽  
Vol 86 (7) ◽  
pp. 55-58
Author(s):  
A. D. Khvan ◽  
D. V. Khvan ◽  
A. A. Voropaev
Keyword(s):  
Plastic Deformation ◽  
Stress State ◽  
Yield Strength ◽  
Bauschinger Effect ◽  
Calculated Data ◽  
Compressive Yield Strength ◽  
Special Device ◽  
Compression Tests ◽  
Traditional Procedure

The Bauschinger effect is one of the fundamental properties of most metal alloys exposed to plastic deformation under non-monotonic loading. Development of the methods for quantifying this effect is one the important issues of the theory of plasticity. Calculation of the parameter characterizing the aforementioned effect is required for determination of the stress state in plastically deformable blanks upon pressure metal treatment. The value of the parameter (determined in standard tensile tests followed by subsequent compression of samples) is defined by the ratio of the conditional yield strength of the sample under compression to the value of the preliminary tensile stress. A series of cylindrical samples (~10 pcs.) is usually taken for tensile-compression tests. According to the traditional procedure, long-size standard specimens are pre-stretched to various degrees of plastic deformation. After that short specimens are cut out from those specimens for compression tests to determine the conditional compressive yield strength with a tolerance of 0.2% for plastic deformation. Such a procedure is rather time consuming and expensive. We propose and develop a new single-model method for estimating the Bauschinger effect which consists in testing of a single long-size specimen for tension followed by compression of the specimen in a special device providing deformation of a previously stretched specimen without flexure under conditions of a linear stress state. The device was designed, manufactured and underwent the appropriate tests. The device contains supporting elements in the form of conical-shaped sectors that prevent flexure of a long cylindrical specimen upon compression, a ratio of the working part length to diameter ranges from 5 to 10. The results of experimental determination of the parameter β characterizing the indicated effect are presented. The results of comparing the values of the parameter β determined by the developed and traditional methods revealed the possibility of determining the parameter β using the proposed method. To reduce the complexity of performing tests related to determination of the parameter β we approximated it in the form of an exponent as a function of the magnitude of plastic deformation and determine the only one value of β0 under plastic deformations exceeding 0.05. In this regard, β0 can be considered a new characteristic of the material. The calculated data are in good agreement with the experimental results. The values of β0 are determined for a number of studied steel grades.

Investigation on the Improvement of Magnetic Properties by Hot Deformation Processes for NdFeB Magnets

2014 ◽  
Vol 626 ◽  
pp. 317-322 ◽  
Author(s):  
Yen Ju Chen ◽  
Chao Cheng Chang ◽  
Po Jen Hsiao ◽  
Can Xun Chang
Keyword(s):  
Plastic Deformation ◽  
Magnetic Properties ◽  
Strain Rate ◽  
Process Parameters ◽  
Effective Strain ◽  
High Energy ◽  
Experimental Results ◽  
Ndfeb Magnets ◽  
Energy Product ◽  
Key Factor

Traditionally, NdFeB magnets with high remanent flux density or high energy product could only be manufactured through altering the material compounds. In recent years, studies indicated that the magnet properties of NdFeB magnets could be improved through plastic deformation. These studies pointed out that the degree of plastic deformation is a key factor to improve magnetic properties. However, there are still many other process parameters that could affect the magnetic properties either positively or negatively. In this paper, process parameters such as strain, strain rate, and temperature are studied to illustrate their influences on the magnetic properties of NdFeB magnets. The magnetic property could be greatly improved when the preferred orientation appears on the microstructure of deformed NdFeB magnets. One of the experimental results showed that the energy product value had been increased by 76.7% when the effective strain value had reached 0.65. Experimental results also showed that strain rate is a dominating factor with regard to the flow stress of material. Through a proper combination of these parameters, one can obtain NdFeB magnets with their magnetic properties greatly improved.

scholarly journals Analysis and Characterization on Dynamic Recrystallization in Casting AZ31 Mg Alloys Under Plane Strain Compression

Materials ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 522
Author(s):  
Li Xu ◽  
Minghua Xiang ◽  
Jun Wang ◽  
Jun Zhang ◽  
Chenning Wang ◽  
...  
Keyword(s):  
Plastic Deformation ◽  
Dynamic Recrystallization ◽  
Strain Rate ◽  
Plane Strain ◽  
Rate Sensitivity ◽  
Local Stress ◽  
Plane Strain Compression ◽  
Mg Alloys ◽  
Coarse Grained ◽  
Compression Tests

Studies on twinning, twin-induced dynamic recrystallization (TDRX), and their temperature and strain rate dependences are of considerable significance to the ultimate strength and plastic formability of the coarse-grained Mg alloys during severe plastic deformation. Plane strain compression tests were conducted on the parallelepiped samples of casting AZ31 Mg alloys. The twinning and recrystallization behaviors close to and away from the crack boundaries were characterized using electron backscatter diffraction. The results show: (1) with increasing strain rate for tests, the extension twin proliferates significantly. Due to the local stress concentration, the TDRX is more active in the area close to the crack tip and exhibits the positive strain-rate sensitivity as twinning; (2) the TDRX is not only stress-favored but also closely links to the temperature. However, the TDRX is not utterly proportional to the temperature. Compared to 400 °C, 300 °C is more beneficial to the TDRX, achieving the higher strength and plastic deformability. The main reason is that the higher strain-hardening rate and flow stress at the higher strain rate and lower temperature motivates the transformation from twinning to the fine twin-walled grains more efficiently, and the stress-favored TDRX is crucial to refine grains and continue plastic deformation for the casting Mg alloys with coarse grains.

scholarly journals Theoretical-Experimental Analysis of the Workability of the Ni50Cr45N0.6 alloy

2017 ◽  
Vol 62 (1) ◽  
pp. 59-65
Author(s):  
A. Łukaszek-Sołek ◽  
A. Świątoniowski ◽  
K. Celadyn ◽  
J. Sińczak
Keyword(s):  
Strain Rate ◽  
Power Dissipation ◽  
Metal Forming ◽  
Flow Instability ◽  
Deformation Behaviour ◽  
True Strain ◽  
Strain Range ◽  
Rate Sensitivity ◽  
Processing Maps ◽  
Compression Tests

Abstract In this paper, the results of investigations into, and of the analyses of, the hot deformation behaviour of the Ni50Cr45N0.6 alloy were presented. Compression tests were conducted on a Gleeble 3800 thermo-mechanical simulator within the following temperatures range 850-1200°C and within that of the strain rate 1-40 s-1 to the constant true strain of 0.9, for the purpose of fulfilling the objective of obtaining experimental stress date. Those data were taken advantage of for the purpose of calculating the workability parameters, and that means the efficiency of power dissipation η, the flow instability ξ and the strain rate sensitivity m. The processing maps based upon Murty’s criterion were drawn up for the following true strain range: 0.2-0.9, and, subsequently, both processing windows and the flow instability areas were determined. For the alloy being analysed, the most advantageous conditions of metal forming were ascertained within the following range of temperatures: 950-1000°C, and for that of the strain rate amounting to 10-40 s-1, and that because of (occurring at the temperature of 950°C) the peak of the efficiency of power dissipation parameter η, amounting to 22% (in accordance with Murty’s criterion). The flow instability areas identified on the processing maps ought to be avoided in metal forming processes. Experimental rolling tests were also conducted.

Determination of the Onset of the Dynamic Recystallization of a 7075 Al Alloy

2013 ◽  
Vol 752 ◽  
pp. 105-114 ◽  
Author(s):  
Tamás Mikó ◽  
Peter Barkoczy
Keyword(s):  
Dynamic Recrystallization ◽  
Strain Rate ◽  
Critical Stress ◽  
Al Alloy ◽  
Strain Rates ◽  
Compression Tests ◽  
Critical Stresses ◽  
Work Hardening Rate ◽  
Initial States

This paper presents an investigation about the occurrence of the dynamic recrystallization (DRX) during hot forming. Two 7075 aluminum alloy samples in different initial states were examined by compression tests at temperatures between 573 K and 723 K and constant strain rates ranging from 0.002 to 2 (s-1) with the maximum strain of 0.5 mm/mm. The activation energies of the examined aluminium were calculated, being 137.7 kJ/mol and 142.4 kJ/mol. The critical stresses and strains for the initiation of the dynamic recrystallization were determined using a numerical method based on the changes of the work hardening rate (θ) as a function of the flow stress (σ) or a strain (ε), respectively. Based on the micrographs taken after the deformations it was revealed that in some cases only dinamyc recovery (DRV) whereas in others DRX occurred under the applied examination conditions. The critical stress which belongs to the onset of the DRX or the DRV depend on the temperature, the strain rate, and the initial grain size. The critical and maximal stresses and the corresponding strain values at different conditions were determined. In the examined range of deformation, temperature and strain rate, the critical rations are σ_c/σ_p= (0.93-0.99) and εc/ εp = (0.3-0.74), respectively.

Effect of Processing Parameters on the Hot Compressive Deformation Behavior of 20CrMnTiH

2011 ◽  
Vol 399-401 ◽  
pp. 1693-1696 ◽  
Author(s):  
Cheng Liang Hu ◽  
Ying Zhang ◽  
Zhen Zhao ◽  
Zhi Liang Zhang
Keyword(s):  
Strain Rate ◽  
Deformation Temperature ◽  
Processing Parameters ◽  
Significant Degree ◽  
Main Process ◽  
Compression Tests ◽  
Gear Steel ◽  
Stress Maximum ◽  
The Impact ◽  
Temperature Strain

20CrMnTiH is widely used as gear steel because of its good hardenability. Based on the Taguchi technique, an L9 orthogonal array was arranged, and the three main process parameters were deformation temperature, strain rate and strain, and their levels were in the range of 850oC~1050oC, 0.1 s-1~10s-1 and 0.2~0.8 respectively. Nine hot compression tests were carried out on a GLEEBLE 1500 simulator, and the stress-strain curves and microstructures were investigated. The experimental results showed that deformation temperature was the most significant parameter of flow stress maximum followed by strain rate and strain, and the impact significant degree of on the grain size after compression was shown in the following: deformation temperature > strain > strain rate.

Experimental study on single point incremental forming of Inconel 718

2020 ◽  
Vol 44 (2) ◽  
pp. 179-188
Author(s):  
S. Pratheesh Kumar ◽  
S. Elangovan ◽  
R. Mohanraj
Keyword(s):  
Sheet Metal ◽  
Process Parameters ◽  
Sheet Metal Forming ◽  
Metal Forming ◽  
Inconel 718 ◽  
Single Point ◽  
Forming Limit ◽  
Manufacturing Cost ◽  
Main Process ◽  
Incremental Sheet Metal Forming

The contemporary sheet metal industry employs forming methods that use a precise die and punch to form components with precise tolerances. In mass production, the high cost of manufacturing dies and punches is absorbed by the number of components formed, whereas this is not the case for low volume production where it increases the manufacturing cost of the products. To overcome the demand for the development of manufacturing technologies that are both agile and meet industrial requirements, an incremental sheet metal forming experiment was carried out on Inconel 718. The incremental sheet metal forming process in the research stage needs to be improved both in terms of accuracy and product quality. The main process parameters involved in the study are incremental depth, rotational speed, and feed rate of the forming tool. Based on the process parameters, experiments are conducted using the Taguchi L9 orthogonal array design and responses such as geometrical accuracy, surface roughness, and thinning are studied. The forming limit and micro-structural study allow us to understand the forming behavior of Inconel 718, which will enhance the applicability of the material.

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