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.

scholarly journals Studies on friction behaviour of aluminium AA4032 alloy during forging using ring compression test

2021 ◽  
Vol 13 (3) ◽  
pp. 23-36
Author(s):  
Desalegn Wogaso ◽  
Mohammed Hamda
Keyword(s):  
Friction Factor ◽  
Metal Surface ◽  
Palm Oil ◽  
Compression Test ◽  
Metal Flow ◽  
Work Piece ◽  
Ring Compression Test ◽  
Ring Compression ◽  
Friction Behaviour ◽  
Selection Of

In metal forming, friction has a negative effect on the deformation load & energy requirements, homogeneity of metal flow, quality of formed surfaces, etc.; however, its effect can be reduced through the use of proper lubricants. Mostly, in industrial applications, selection of proper lubricant for specific material is challenging and quantification of magnitude of friction at diework piece interface is essential. Hence, for metallic alloys, a realistic friction factor is needed to be known and used at the diework piece interface for better control of deformation process. Thus, this research, generally, aims at experimental investigation of the friction behavior of aluminum AA4032 alloy and selection of suitable lubricant for its effective processing using ring compression test and finite element (FE) simulations. Meanwhile, the effect of metal surface conditions and different lubricants namely palm oil, grease, emulsion oil and dry conditions on the friction behaviour has been evaluated. A commercial FEM software, DEFORM 3D, is used to analyze the flow of metal, determine the geometry changes of the specimen and generate friction calibration curves. The results revealed that the nature of metal surface and lubricating conditions have significantly affected the metal flow pattern, deformation load requirement, induced effective stress and strain, and geometry of the metal. The friction factor at die-work piece is determined for different lubricating conditions. Among lubricants employed, palm oil is found to be suitable and effective for industrial processing of aluminium AA4032 alloy, specifically for forging. The FE simulation results are in a good agreement with the experimental one.

Interfacial Friction of Ceramics at High Temperature Ring-Compression Test

2011 ◽  
Vol 704-705 ◽  
pp. 967-972
Author(s):  
Hui Gai Wang ◽  
Yan Pei Song ◽  
Fei Wang ◽  
Kai Feng Zhang
Keyword(s):  
High Temperature ◽  
Boron Nitride ◽  
Friction Factor ◽  
Compression Test ◽  
Elevated Temperatures ◽  
Interfacial Friction ◽  
Average Pressure ◽  
Compression Tests ◽  
Ring Compression Test ◽  
Ring Compression

Using ring compression tests, the interfacial friction and flow stress of 3Y-TZP/Al2O3 composite at elevated temperatures were investigated. Theoretical calibration curves of the friction factor and the relative average pressure curves for the ring compression tests of 6:3:2 standard rings were drawn based on a velocity field capable of describing the bulge phenomena. The lubricant was the boron nitride (hexagonal). The tests were adopted at temperature range of 1400°C-1600°C. Results indicate that the interfacial friction factor has the value in the range of 0.34-0.49, so that boron nitride lubricant can be used effectively in present temperatures. As two extremely important parameters, the temperature and strain rate have no significant effect on the fraction factor. It is proved reliable that the ring-compression test at 1400°C and even higher is used to evaluate the performance of boron nitride lubricant.

The Research on Ceramic Friction and Flow Stress of Plastic Forming

2014 ◽  
Vol 887-888 ◽  
pp. 1313-1316
Author(s):  
Zhan Jun Liu
Keyword(s):  
Flow Stress ◽  
Friction Factor ◽  
Flow Behavior ◽  
Workpiece Material ◽  
Interface Friction ◽  
Incremental Method ◽  
Ring Compression ◽  
Plastic Forming ◽  
Actual Flow ◽  
Standard Calibration

The interface friction is used to evaluate the plastic flow behavior of workpiece material in different conditions such as temperature, pressure, strain rate and strain distribution. It is analyzed that deformation and material flow by the ring compression method during compression, which is contained with the theoretical calculation of different interface friction ring inside diameter and the height of the change. The progressive deformation incremental method is studied to the curve of the friction factor and ring size. It is given that the standard calibration curve of ring friction factor by 6:3:2 size ratio. According to the practical circle deformation ,it is given to the relative average stress, and then to calculate the average normal stress, according to the actual load stress ,it can be concluded that the actual flow stress of material. The change of ring height and diameter is measured by experiment. The results show that the friction factor is relatively stable, the maximum is 0.48, and then the minimum is 0.35.

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.

Investigating Friction Factor in Forging of Ti-6Al-4V through Isothermal Ring Compression Test

2015 ◽  
Vol 58 (5) ◽  
pp. 778-785 ◽  
Author(s):  
S. Javid Mirahmadi ◽  
Mohsen Hamedi ◽  
Mohammad Cheraghzadeh
Keyword(s):  
Friction Factor ◽  
Compression Test ◽  
Ring Compression Test ◽  
Ring Compression

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.

Determination of the friction factor of Ti-6Al-4V titanium alloy in hot forging by means of ring-compression test using FEM

2011 ◽  
Vol 44 (12) ◽  
pp. 2074-2080 ◽  
Author(s):  
Yanchun Zhu ◽  
Weidong Zeng ◽  
Xiong Ma ◽  
Qingan Tai ◽  
Zhihua Li ◽  
...  
Keyword(s):  
Titanium Alloy ◽  
Friction Factor ◽  
Compression Test ◽  
Hot Forging ◽  
Ring Compression Test ◽  
Ring Compression

The Effect of Ultrasonic-Vibration on Upsetting

2006 ◽  
Author(s):  
Jung-Chung Hung ◽  
Yu-Chung Tsai ◽  
Chinghua Hung
Keyword(s):  
Aluminum Alloy ◽  
Ultrasonic Vibration ◽  
Compression Test ◽  
Cylindrical Specimen ◽  
Compressive Force ◽  
Specimen Size ◽  
Experimental Results ◽  
Ring Compression Test ◽  
Interface Friction ◽  
Ring Compression

Ultrasonic-vibration upsetting is a process in which a cylindrical specimen is compressed by an axial force while the ultrasonic vibration is simultaneously applied to the die. Homogenous deformation is difficult to achieve during this process because of the friction at the interface between the specimen and the die. An extrapolated compression test was performed in this study on aluminum alloy specimens to explore the effect of superimposing ultrasonic-vibration during upsetting. Experimental results indicate that ultrasonic-vibration reduced the compressive force when the friction was eliminated by the extrapolated compression test. The specimen size also influences the force-reducing effects of ultrasonic-vibration. The decrease in the compressive force is smaller for a larger specimen. The barreling profile of the specimen after test indicates that the interface friction will increase during ultrasonic-vibration compression. Additionally, the raised material temperatures are caused by ultrasonic-vibration. Experimental results of the hot extrapolated compression test and the hot ring compression test indicate that the drop in the flow stress and the increase in the interface friction are caused by the increase in the temperature of the material under ultrasonic vibration.

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