Metal flow in compression of tubular parts: predictions made with different computer programs and effect of flow stress data

1989 ◽  
Vol 60 (5) ◽  
pp. 201-207 ◽  
Author(s):  
Gerhard Hirt ◽  
Taylan Altan
Keyword(s):  
Flow Stress ◽  
Metal Flow ◽  
Computer Programs ◽  
Flow Stress Data

Influence of Flow Stress and Friction Upon Metal Flow in Upset Forging of Rings and Cylinders

1972 ◽  
Vol 94 (3) ◽  
pp. 775-782 ◽  
Author(s):  
C. H. Lee ◽  
T. Altan
Keyword(s):  
Flow Stress ◽  
Velocity Field ◽  
Strain Rate ◽  
Calibration Curve ◽  
Upper Bound ◽  
Metal Flow ◽  
Computer Programs ◽  
Ring Test ◽  
Stress Distributions ◽  
Upset Forging

An upper-bound velocity field that considers bulging has been applied to cylinder and ring upsetting. Computer programs have been developed to (a) determine strain, strain rate, velocity, and flow-stress distributions, and (b) predict load and bulge profile at various reductions by simulating the upsetting process. The calibration curve for a 6:3:2 ring, the load-displacement curves for ring and cylinder upsetting, and flow stress from the ring test have been predicted. The experimental results, with annealed 1100 Aluminum samples, agree well with theory at the lower and practical range of friction, but they show some disagreement at high friction.

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.

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

SIMULATION OF MULTI-PASS HOT ROLLING BY A MIXED ANALYTICAL-NUMERICAL METHOD

2011 ◽  
Vol 03 (03) ◽  
pp. 469-489 ◽  
Author(s):  
JINLING ZHANG ◽  
ZHENSHAN CUI
Keyword(s):  
Mathematical Model ◽  
Flow Stress ◽  
Strain Rate ◽  
Numerical Method ◽  
Hot Rolling ◽  
High Efficiency ◽  
Rolling Force ◽  
Metal Flow ◽  
Fem Simulation ◽  
Rolling Process

A mathematical model integrating analytical method with numerical method was established to simulate the multi-pass plate hot rolling process, predicting its strain, strain rate, stress and temperature. Firstly, a temperature analytical model was derived through series function solution, the coefficients in which for successive processes were smoothly transformed from the former process to the latter. Therefore, the continuous computation of temperature for multi-operation and multi-pass was accomplished. Secondly, kinematically-admissible velocity function was developed in Eulerian coordinate system according to the principle of volume constancy and characteristics of metal flow during rolling with undetermined coefficients — which were eventually solved by Markov variational principle. Thirdly, strain rate was calculated through geometric equations and the difference-equations for solving strain and a subsequent recurrent solution were established. Fourthly, rolling force was calculated on the base of Orowan equilibrium equation, considering the contribution to flow stress of strain, strain rate and temperature, rather than taking the flow stress as a constant. Consequently, the thermo-mechanics and deformation variables are iteratively solved. This model was employed in the simulation of an industrial seven-pass plate hot rolling schedule. The comparisons of calculated results with the measured ones and the FEM simulation results indicate that this mathematical model is able to reasonably represent the evolutions of various variables during hot rolling so it can be used in the analysis of practical rolling. Above all, the greatest advantage of the presented is the high efficiency. It costs only 12 seconds to simulate a seven-pass schedule, more efficient than any other numerical methods.

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.

Sign in / Sign up

Export Citation Format

Share Document