Analysis of Ring Compression Test for Determination of Friction Circumstances in Forging Process

2012 ◽  
Vol 249-250 ◽  
pp. 663-666 ◽  
Author(s):  
Mojtaba Dehghan ◽  
Fathallah Qods ◽  
Mahdi Gerdooei ◽  
Javad Doai
Keyword(s):  
Friction And Wear ◽  
Fe Analysis ◽  
Ring Test ◽  
Ring Compression Test ◽  
Friction Behavior ◽  
Forging Process ◽  
Calibration Curves ◽  
Ring Compression ◽  
Friction Calibration

Friction is a major factor in determining the characteristics ofmetals as they are forged.Regularand efficient lubrication is one of the best ways in controlling friction and wear in this process.One of the best ways of testing the lubricant is the ringCompression test. In this research the effect of mixed graphite in water and also the effect of the amount of graphite in the lubricant in the reduction of friction between the sample-die are calculated using the ring test. Friction behavior is changed fromsticking friction to sliding frictionby using the lubricant; but the changes in the amount of graphite in water didnot have a great effect on the reduction of the friction coefficient. Furthermore, after viewing differences in the friction coefficients calculated by the means of FE analysis and the friction calibration curves, it is concluded that the sole calibration curves could not be used for hot working conditions.

Development of Lubricants Evaluation for Different Friction Laws by Using Rigid-Plastic Finite Element Method

2012 ◽  
Vol 626 ◽  
pp. 584-588
Author(s):  
Heng Keong Kam ◽  
Wen Chiet Cheong ◽  
Chan Chin Wang ◽  
Ying Pio Lim
Keyword(s):  
Finite Element Method ◽  
Coulomb Friction ◽  
Ring Compression Test ◽  
Rigid Plastic ◽  
Friction Law ◽  
Calibration Curves ◽  
Ring Compression ◽  
Shear Friction ◽  
Coulomb Friction Law ◽  
Friction Calibration

A simulator based on rigid-plastic finite element method is developed with two common friction law: Coulomb friction law and constant shear friction law are imposed. This project is to develop a simple method to identify tribological properties of various lubricants by metal forming method. In this project, the influence of different lubricants was studied by using ring compression test. The deformation of the ring compression test was measured to obtain an experimental friction calibration curves under different lubricants. To model the friction effect, theoretical friction calibration curves for Coulomb friction law and shear friction law are generated under various parameter of μ, coefficient of friction (Coulomb friction law) and m, shear factor (constant shear friction law). The experimental and theoretical friction calibration curves were compared and the result shows corresponding. The friction of the lubricants was further verified by using a common method: pulling a block on flat surface with load sensor yields the friction force, F in the basic equation F=μN where N is the normal force. The results match the calibration curves too.

A Method for Determination of Friction Coefficient in Sheet Metal Forming of Magnesium Alloy

2012 ◽  
Vol 268-270 ◽  
pp. 430-435 ◽  
Author(s):  
Xin Wu Ma ◽  
Guo Qun Zhao ◽  
Wen Juan Li
Keyword(s):  
Friction Coefficient ◽  
Sheet Metal ◽  
Sheet Metal Forming ◽  
Metal Forming ◽  
Dimensional Change ◽  
Analysis Model ◽  
Calibration Curves ◽  
Set Up ◽  
Friction Calibration

A new method for determination of friction coefficient in sheet metal forming of Mg alloy AZ31B is presented in this paper. The method is based on the bulging test of sheet metal in which the specimen is processed with a hole at the center. The diameter of the hole will increase along the stroke of the punch and the dimensional change of the hole has a certain relationship with the friction coefficient at the punch/specimen interface. Thus, the friction coefficient can be determined indirectly according to the dimension of the hole in the bulging process. The bulging process of the sheet is simulated using FE code DEFORM-2D. The analysis model is set up according to the experiment of the bulging and the friction calibration curves are generated from the simulations of the bulging by setting different coefficients of friction. The friction coefficient can be determined by measuring the hole dimension during the bulging process and comparing it with the friction calibration curves.

The Validity of Mathematical Solutions for Determining Friction From the Ring Compression Test

1970 ◽  
Vol 92 (3) ◽  
pp. 389-395 ◽  
Author(s):  
Alan T. Male ◽  
Vincent DePierre
Keyword(s):  
Friction Factor ◽  
Ring Test ◽  
Theoretical Treatment ◽  
Specimen Thickness ◽  
Test Results ◽  
Ring Compression Test ◽  
Excellent Correlation ◽  
Interface Friction ◽  
Ring Compression ◽  
Shape Changes

The ring test has previously been experimentally calibrated for friction studies on the assumption of constant coefficient of friction under metal-working conditions. This investigation has demonstrated that the same experimental results may be used to calibrate the ring test on the assumption of constant interface friction factor. Use of available mathematical solutions, based on the concept of a constant interface friction factor, provides a possible means for the calibration of different initial ring geometries by computer solution. Excellent correlation has been shown between the shape of calculated curves and experimental ring test results on a wide variety of materials. However, the actual values of m obtained by using the theory to analyze experimentally determined shape changes appear to be somewhat in error to a degree depending on the initial specimen geometry and the general friction level under which it is deformed. This is due essentially to the assumption used in the theoretical treatment, that the surface frictional stresses are transmitted uniformly throughout the specimen thickness, not being generally valid in the practical situation except with very thin specimens.

Determination of Friction Coefficient by Employing the Ring Compression Test

2000 ◽  
Vol 123 (3) ◽  
pp. 338-348 ◽  
Author(s):  
Hasan Sofuoglu ◽  
Hasan Gedikli ◽  
Jahan Rasty
Keyword(s):  
Finite Element ◽  
Friction Coefficient ◽  
Material Properties ◽  
Rate Sensitivity ◽  
Compression Tests ◽  
Element Analysis ◽  
Test Conditions ◽  
Calibration Curves ◽  
Ring Compression ◽  
Friction Calibration

The main objective of this research was to investigate the effect of material properties, strain-rate sensitivity, and barreling on the behavior of friction calibration curves. The compression tests were conducted to obtain the necessary material properties for the finite element analysis. A series of ring compression tests were then conducted in order to determine the magnitude of the friction coefficient, μ. The experiments were first conducted for the modeling materials, namely, white and black plasticine and later on, for aluminum, copper, bronze, and brass. The experiments were then simulated via an elastic-plastic finite element code (ABAQUS). Contrary to the results available in the literature, where the same friction calibration curves are recommended for all types of materials and test conditions, the results of this investigation showed that friction calibration curves are indeed affected by the material properties and test conditions.

scholarly journals Estimation of friction by using improved calibration curves of ring compression test for hot forging of steel

2017 ◽  
Vol 207 ◽  
pp. 2280-2285 ◽  
Author(s):  
Kazuhito Asai ◽  
Kazuhiko Kitamura ◽  
Nobuki Yukawa ◽  
Nobukazu Hayashi
Keyword(s):  
Compression Test ◽  
Hot Forging ◽  
Ring Compression Test ◽  
Calibration Curves ◽  
Ring Compression

FEM Simulation Analysis of Ring Compression Test Using Stationary and Rotating Die under Constant Shear Friction

2020 ◽  
Vol 830 ◽  
pp. 15-28
Author(s):  
Wayne Stalls ◽  
Un Chin Chai ◽  
Tim Pasang ◽  
Gow Yi Tzou
Keyword(s):  
Friction Factor ◽  
Compression Test ◽  
Simulation Analysis ◽  
Metal Flow ◽  
Fem Simulation ◽  
Compressive Force ◽  
Reduction Ratio ◽  
Ring Compression Test ◽  
Ring Compression ◽  
Friction Calibration

The main objective of this research was to investigate the effect of friction on the behaviour of the metal flow and ring geometry, using comparisons from a stationary and rotating bottom die. This was carried out using friction calibration curves, compressive force analysis, stress and strain relationships and the reduction ratio of the ring specimen. The ring compression test (RCT) is considered one of the most reliable ways to obtain the friction factor existing in a plastic deformation process. This technique utilizes the dimensional changes of a test specimen to determine the magnitude of the friction factor. The variation of the calibration curve for the stationary die, with a range of m=0.0 to 0.9, and for the rotating die a range of m=0.1, 0.5 and 0.9. The frictional factor is calculated using FEM analysis, friction calibration and reduction ratio curves were generated from the compressive force using the DEFORM software package. The results indicated that the change in the inner diameter is related to the friction conditions and angular velocities at the die-workpiece interface.

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