Use of Axisymmetric Shearing as Technological Test Method to gather Flow Stress Data for Metals

2011 ◽  
Author(s):  
Janis Kandis ◽  
Henry Valberg ◽  
Wu Wenbin ◽  
Francisco Chinesta ◽  
Yvan Chastel ◽  
...  
Keyword(s):  
Flow Stress ◽  
Test Method ◽  
Technological Test ◽  
Flow Stress Data

Cutting applied as test method for acquisition of flow stress data at high strains and strain rates

2008 ◽  
Vol 1 (S1) ◽  
pp. 519-522 ◽  
Author(s):  
S. M. Ganesan ◽  
Y. A. Khan ◽  
H. Valberg ◽  
P. T Moe ◽  
A. Willa Hansen
Keyword(s):  
Flow Stress ◽  
Test Method ◽  
Strain Rates ◽  
Flow Stress Data

Flow Behaviour and Ductile Fracture Toughness of a High Toughness Steel

2004 ◽  
Author(s):  
S. Xu ◽  
R. Bouchard ◽  
W. R. Tyson
Keyword(s):  
Flow Stress ◽  
Ductile Fracture ◽  
Tensile Tests ◽  
Test Method ◽  
Opening Angle ◽  
Absorbed Energy ◽  
Crack Propagation Resistance ◽  
High Toughness ◽  
Drop Weight ◽  
Drop Weight Tear Test

This paper reports results of tests on flow and ductile fracture of a very high toughness steel with Charpy V-notch absorbed energy (CVN energy) at room temperature of 471 J. The microstructure of the steel is bainite/ferrite and its strength is equivalent to X80 grade. The flow stress was determined using tensile tests at temperatures between 150°C and −147°C and strain rates of 0.00075, 0.02 and 1 s−1, and was fitted to a proposed constitutive equation. Charpy tests were carried out at an initial impact velocity of 5.1 ms−1 using drop-weight machines (maximum capacity of 842 J and 4029 J). The samples were not broken during the test, i.e. they passed through the anvils after significant bending deformation with only limited crack growth. Most of the absorbed energy was due to deformation. There was little effect of excess energy on absorbed energy up to 80% of machine capacity (i.e. the validity limit of ASTM E 23). As an alternative to the CVN energy, the crack tip opening angle (CTOA) measured using the drop-weight tear test (DWTT) has been proposed as a material parameter to characterize crack propagation resistance. Preliminary work on evaluating CTOA using the two-specimen CTOA test method is presented. The initiation energy is eliminated by using statically precracked test specimens. Account is taken of the geometry change of the specimens (e.g. thickening under the hammer) on the rotation factor and of the effect of strain rate on flow stress.

The Effect of Material Flow Stress on Analytical Simulation of Machining

2010 ◽  
Vol 29-32 ◽  
pp. 1809-1814
Author(s):  
Bing Lin Li ◽  
Ling Ling ◽  
Yu Jin Hu ◽  
Xue Lin Wang
Keyword(s):  
Flow Stress ◽  
Shear Zone ◽  
Analytical Model ◽  
Material Flow ◽  
Model Simulation ◽  
Orthogonal Cutting ◽  
Shear Plane ◽  
Thermomechanical Model ◽  
Workpiece Material ◽  
Flow Stress Data

The flow stress data of the workpiece are extremely crucial for the cutting simulation. The study shows how the input data affect the analytical predictions of cutting force and temperature. The Johnson-Cook material model is used to represent workpiece flow stress in the primary shear zone. A thermomechanical model of orthogonal cutting is proposed based on the main shear plane divides the primary shear zone into two unequal parts. Five different sets of workpiece material flow stress data used in the Johnson-Cook’s constitutive equation are chosen and make the sensitivity analysis for analytical model. Simulation results were compared to orthogonal cutting test data from the available literature, and find the effects of flow stress on analytical model was different from that for finite element model.

Flow Stress Experimental Determination for Warm-Forming Process

2011 ◽  
Author(s):  
Ting Fai Kong ◽  
Luen Chow Chan ◽  
Tai Chiu Lee
Keyword(s):  
Stainless Steel ◽  
Flow Stress ◽  
Room Temperature ◽  
Warm Forming ◽  
Recrystallization Temperature ◽  
Process Conditions ◽  
Compression Tests ◽  
Forming Process ◽  
Forming Temperature ◽  
Flow Stress Data

Warm forming is a manufacturing process in which a workpiece is formed into a desired shape at a temperature range between room temperature and material recrystallization temperature. Flow stress is expressed as a function of the strain, strain rate, and temperature. Based on such information, engineers can predict deformation behavior of material in the process. The majority of existing studies on flow stress mainly focus on the deformation and microstructure of alloys at temperature higher than their recrystallization temperatures or at room temperature. Not much works have been presented on flow stress at warm-forming temperatures. This study aimed to determine the flow stress of stainless steel AISI 316L and titanium TA2 using specially modified equipment. Comparing with the conventional method, the equipment developed for uniaxial compression tests has be verified to be an economical and feasible solution to accurately obtain flow stress data at warm-forming temperatures. With average strain rates of 0.01, 0.1, and 1 /s, the stainless steel was tested at degree 600, 650, 700, 750, and 800 °C and the titanium was tested at 500, 550, 600, 650, and 700 °C. Both materials softened at increasing temperatures. The overall flow stress of stainless steel was approximately 40 % more sensitive to the temperature compared to that of titanium. In order to increase the efficiency of forming process, it was suggested that the stainless steel should be formed at a higher warm-forming temperature, i.e. 800 °C. These findings are a practical reference that enables the industry to evaluate various process conditions in warm-forming without going through expensive and time consuming tests.

Simulation of Deform Behavior of WE43 Magnesium Alloy Based on DEFORM-3D

2009 ◽  
Vol 618-619 ◽  
pp. 191-194 ◽  
Author(s):  
Qiang Wang ◽  
Jia Cheng Gao ◽  
Wen Juan Niu
Keyword(s):  
Flow Stress ◽  
Magnesium Alloy ◽  
Computational Simulation ◽  
Forming Process ◽  
Actual Operation ◽  
Actual Flow ◽  
Flow Stress Data ◽  
The Cost ◽  
Deform 3D ◽  
We43 Magnesium Alloy

Compared with the actual operation, computational simulation will save the cost and provide more valuable references or guiding significance for the real production. Using professional forming software DEFORM-3D, the upsetting process of WE43 magnesium alloy was simulated. Based on the actual flow stress data, the simulation model of WE43 magnesium alloy was created in DEFORM-3D. Results show that the uniform distribution of the temperature of WE43 magnesium alloy during the forming process is beneficial to the structural homogeneity and contributes to excellent flowing property. There is the stress concentration in the edge and slide face of the billet. So during the process of compression, the fracture will appear earlier in the edge and slide face of the sample.

Development of Processing Map for Superplastic Deformation of Ti-6Al-4V Alloy

2018 ◽  
Author(s):  
Mohd Abdul Wahed ◽  
Amit Kumar Gupta ◽  
Nitin Ramesh Kotkunde ◽  
Swadesh Kumar Singh
Keyword(s):  
Flow Stress ◽  
Strain Rate ◽  
Superplastic Deformation ◽  
Processing Map ◽  
Flow Instability ◽  
Hot Working ◽  
Uniaxial Tensile ◽  
Temperature Range ◽  
Instability Map ◽  
Flow Stress Data

A processing map plays a major role in indicating safe and failure regions of a process conducted in a hot working regime. It also shows the response of a material, by indicating changes in the microstructural evolution through temperature. In the present study, a processing map has been developed depending on the flow stress data of Ti-6Al-4V alloy sheet in a strain rate range of 10−2 /s to 10−4 /s and over a temperature range of 700°C to 900°C in order to identify the presence of superplasticity region. The flow stress data have been acquired on the basis of temperature, strain and strain rate by conducting hot uniaxial tensile tests. Based on this, a power dissipation map is obtained to show the percentage of efficiency, as it is directly related to the amount of internal entropy produced. In addition, an instability map is also obtained, as it identifies the flow instability that are to be avoided during hot working process. Finally, a processing map has been established by overlaying instability map on efficiency map. The results clearly reveal that the superplastic deformation occurs within a temperature range of 750°C to 900°C at a strain rate of 10−4 /s, without any flow instability in this region.

From Orthogonal Cutting Experiments towards Easy-to-Implement and Accurate Flow Stress Data

2013 ◽  
Vol 28 (11) ◽  
pp. 1222-1227 ◽  
Author(s):  
F. Klocke ◽  
D. Lung ◽  
S. Buchkremer ◽  
I. S. Jawahir
Keyword(s):  
Flow Stress ◽  
Orthogonal Cutting ◽  
Flow Stress Data ◽  
Cutting Experiments

Study on Constitutive Model of 20CrMnTi Gear Steel in Cutting Process

2011 ◽  
Vol 291-294 ◽  
pp. 311-317 ◽  
Author(s):  
Gan Hua Liu ◽  
Hong Zhi Yan
Keyword(s):  
Flow Stress ◽  
Constitutive Model ◽  
Metal Cutting ◽  
Cutting Process ◽  
Comprehensive Method ◽  
Model Flow ◽  
Gear Steel ◽  
Cutting Deformation ◽  
Flow Stress Data ◽  
Gear Steels

Flow stress data is important base data in using the analytical method and the finite element method to analyze the metal cutting process.In the present study, a comprehensive method combining with four methods of material mechanics tests, SHTB impact tests, two-dimensional orthogonal slot milling experiments and reverse solving is used to determine constitutive model (flow stress model) as a function of the "three-high" (high strain , temperature and strain rate) in metal cutting. The constitutive model of 20CrMnTi gear steel (hardened to170±5HB) which is one of China’s main gear steels in cutting deformation is established by using this method, and experimental results show that the model’s accuracy is high. Practice has proved that the methodology of constitutive model determination for metal cutting deformation, proposed in the present study, has advantages when compared with using one method alone, and is more suitable to establish flow data for the various materials in the metal cutting process.

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