Determination of Friction in Sheet Metal Forming by Means of Simulative Tribo-Tests

2013 ◽  
Vol 549 ◽  
pp. 415-422 ◽  
Author(s):  
Ermanno Ceron ◽  
Nils Bay
Keyword(s):  
Coefficient Of Friction ◽  
Tool Material ◽  
Workpiece Material ◽  
Weakest Link ◽  
Tool Coating ◽  
Sheet Stamping ◽  
The Coefficient Of Friction ◽  
Tension Testing ◽  
Strip Testing ◽  
Bending Under Tension

Numerical modeling of complex sheet stamping operations is well developed and implemented in industry. The weakest link now seems to be appropriate modeling of friction and to some extent also material properties especially when it comes to new lubricants and materials. In modeling of 3-D stamping operations a coefficient of friction μ is often determined by calibration of the simulation results with experimental observations of material flow and/or measured load. In case of modeling of new stamping operations μ is typically selected based on former experience. These procedures are, however, not appropriate when introducing new tribo-systems (lubricant, workpiece material, tool material or tool coating). In order to determine friction under the very varied conditions in sheet stamping simulative testing may be applied, e.g., Plane-Strip-Testing (PST), Draw-Bead-Testing (DBT) and Bending-Under-Tension testing (BUT) but these tests should be analyzed and carefully tuned with the production process in question to ensure useful results. The present paper illustrates how the BUT test combined with classical analytical modeling may lead to very large errors in estimation of the coefficient of friction, whereas detailed numerical simulation of the test can give useful friction values as demonstrated in comparative analysis of an industrial, multistage deep drawing.

scholarly journals Thermomechanical Analysis of Friction Stir Welding by Using a New Velocity-Based Model for Tool-Workpiece Interaction

2021 ◽  
Author(s):  
Zhen Sun ◽  
Pengfei Liu ◽  
Xinghua Yu
Keyword(s):  
Friction Stir Welding ◽  
Coefficient Of Friction ◽  
Transverse Cross Section ◽  
Thermomechanical Analysis ◽  
Maximum Temperature ◽  
Contact Interface ◽  
Workpiece Material ◽  
Friction Stir ◽  
Boundary Velocity ◽  
The Coefficient Of Friction

Abstract The friction stir spot welding test was designed to measure the coefficient of friction on the tool-workpiece contact interface under different tool rotation speeds. The boundary velocity of the workpiece material was calculated based on the stress state of the material on the contact interface. An integrated computational fluid dynamics (CFD) model of friction stir welding (FSW) was established based on the matrix's coefficient of friction and boundary velocity to simulate heat and mass transfer. A more realistic boundary velocity distribution was acquired. A method was introduced to predict strain along a streamline by integrating the strain rate along with the streamline's reverse. The nephogram of strain on the transverse cross-section of weldment displays that strain at the advancing side (AS) is more significant than that at the retreating side (RS), and strain increases as the distance from the shoulder surface decrease. Strain in some regions can be tremendous if the material flows through the rotation flow zone. Wall heat flux on tool-workpiece contact interface at RS is more significant than that at AS. The maximum temperature was observed at the front part of RS. The model is validated since the predicted temperature profile agrees well with corresponding experimental results.

scholarly journals Testing Tool Material on Scratch Tester

2021 ◽  
Vol 9 (12) ◽  
pp. 1926-1930
Author(s):  
Saurav Salunke
Keyword(s):  
Manufacturing Industry ◽  
Metal Cutting ◽  
Cutting Tools ◽  
Tool Material ◽  
Workpiece Material ◽  
Research Article ◽  
Base Parameters ◽  
Tool Coating ◽  
Testing Tool ◽  
Cutting Operation

Abstract: In manufacturing industry cutting tools are considered as the backbone of the metal cutting operation. In metal cutting operation there is relative motion between the tool and the workpiece. As the tool material is harder than the workpiece material, there is deformation of the workpiece which acts as a base for the formation of chips. If we observe the process of metal cutting, we can easily find out that there is a considerable amount of heat generated during the machining operation. As there is a point of interface between the tool and the workpiece, there is absorption of generated heat into both the tool as well as work material. Due to the absorption of the heat there is distortion in the tool material. In this research article we have taken the base parameters as speed, load and stroke and the output parameter is taken as the load which breaks the coating of the tool. Keywords: tool coating, scratch tester, speed, stroke, coating.

scholarly journals A Study of the Coefficient of Friction in Steel Sheets Forming

Metals ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 988 ◽  
Author(s):  
Tomasz Trzepiecinski
Keyword(s):  
Contact Pressure ◽  
Coefficient Of Friction ◽  
Tribological Properties ◽  
Steel Sheet ◽  
Rolling Direction ◽  
Tension Test ◽  
Drawing Test ◽  
Strip Drawing ◽  
The Coefficient Of Friction ◽  
Bending Under Tension

The aim of this paper was to compare the tribological properties of a deep drawing quality steel sheet using the three commonly used friction tests, i.e., the strip drawing test, draw bead test, and bending under tension test. All tests have been carried out using a specially designed friction simulator. The test material was a 0.8-mm-thick DC04 steel sheet, commonly used in the automotive industry. Uniaxial tensile tests have been carried out to characterise the mechanical properties of the specimens. Furthermore, measurements of the sheet surface topography have been carried out to characterise the tribological properties of the specimens. The friction tests have been conducted under different pressure and lubrication conditions, surface roughnesses of tools represented by counter-samples, and orientations of the specimens according to the direction of the sheet rolling. A comparative analysis of the results of the friction tests revealed different values of friction. In the strip drawing test, the value of the coefficient of friction decreases as the contact pressure increases for both dry and lubricated conditions. In the draw bead test, the specimens oriented along the rolling direction demonstrated a higher value of the coefficient of friction compared to the samples cut transverse to the rolling direction. In contrast to the strip drawing test, the specimens tested in the bending under tension test exhibit a tendency to an increase in the value of the coefficient of friction with the increasing contact pressure.

The Important Influencing Factors of Coefficient of Friction Testing on Metallic Sheet and Strip

2012 ◽  
Vol 503-504 ◽  
pp. 529-532
Author(s):  
Huan Xue ◽  
Rong Feng Li ◽  
Hong Chuan Zhu ◽  
Wen Jie Peng
Keyword(s):  
Coefficient Of Friction ◽  
Test Results ◽  
Friction Test ◽  
Testing Method ◽  
Friction Testing ◽  
Specimen Width ◽  
The Coefficient Of Friction ◽  
Strip Testing ◽  
Metallic Sheet ◽  
Lubrication Conditions

The importance of the coefficient of friction test in sheet metal forming field is introduced. Metallic sheet and strip testing method for coefficient of friction is described, the experimental principle of the testing method is introduced. Three important factors, which will obviously effects the test results, including testing mould, specimen width and surface lubrication conditions have been carefully studied. The comparatively stable testing technologies have been developed to guide the test.

Experimental Investigation of aluminum doping crumb rubber/epoxy composite in reciprocating motion

2015 ◽  
Vol 3 ◽  
pp. 1
Author(s):  
Goutam Chandra Karar ◽  
Nipu Modak
Keyword(s):  
Experimental Investigation ◽  
Coefficient Of Friction ◽  
Epoxy Composite ◽  
Normal Load ◽  
Crumb Rubber ◽  
The Other ◽  
Reciprocating Motion ◽  
Molding Process ◽  
Friction Tester ◽  
The Coefficient Of Friction

The experimental investigation of reciprocating motion between the aluminum doped crumb rubber /epoxy composite and the steel ball has been carried out under Reciprocating Friction Tester, TR-282 to study the wear and coefficient of frictions using different normal loads (0.4Kg, 0.7Kgand1Kg), differentfrequencies (10Hz, 25Hz and 40Hz).The wear is a function of normal load, reciprocating frequency, reciprocating duration and the composition of the material. The percentage of aluminum presents in the composite changesbut the other components remain the same.The four types of composites are fabricated by compression molding process having 0%, 10%, 20% and 30% Al. The effect of different parameters such as normal load, reciprocating frequency and percentage of aluminum has been studied. It is observed that the wear and coefficient of friction is influenced by the parameters. The tendency of wear goes on decreasing with the increase of normal load and it is minimum for a composite having 10%aluminum at a normal load of 0.7Kg and then goes on increasing at higher loads for all types of composite due to the adhesive nature of the composite. The coefficient of friction goes on decreasing with increasing normal loads due to the formation of thin film as an effect of heat generation with normal load.

scholarly journals Tribological Aspects, Optimization and Analysis of Cu-B-CrC Composites Fabricated by Powder Metallurgy

Materials ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4217
Author(s):  
Üsame Ali Usca ◽  
Mahir Uzun ◽  
Mustafa Kuntoğlu ◽  
Serhat Şap ◽  
Khaled Giasin ◽  
...  
Keyword(s):  
Weight Loss ◽  
Wear Rate ◽  
Coefficient Of Friction ◽  
Applied Load ◽  
Practical Significance ◽  
Tribological Characteristics ◽  
M 10 ◽  
Wide Range ◽  
The Coefficient Of Friction ◽  
Four Levels

Tribological properties of engineering components are a key issue due to their effect on the operational performance factors such as wear, surface characteristics, service life and in situ behavior. Thus, for better component quality, process parameters have major importance, especially for metal matrix composites (MMCs), which are a special class of materials used in a wide range of engineering applications including but not limited to structural, automotive and aeronautics. This paper deals with the tribological behavior of Cu-B-CrC composites (Cu-main matrix, B-CrC-reinforcement by 0, 2.5, 5 and 7.5 wt.%). The tribological characteristics investigated in this study are the coefficient of friction, wear rate and weight loss. For this purpose, four levels of sliding distance (1000, 1500, 2000 and 2500 m) and four levels of applied load (10, 15, 20 and 25 N) were used. In addition, two levels of sliding velocity (1 and 1.5 m/s), two levels of sintering time (1 and 2 h) and two sintering temperatures (1000 and 1050 °C) were used. Taguchi’s L16 orthogonal array was used to statistically analyze the aforementioned input parameters and to determine their best levels which give the desired values for the analyzed tribological characteristics. The results were analyzed by statistical analysis, optimization and 3D surface plots. Accordingly, it was determined that the most effective factor for wear rate, weight loss and friction coefficients is the contribution rate. According to signal-to-noise ratios, optimum solutions can be sorted as: the highest levels of parameters except for applied load and reinforcement ratio (2500 m, 10 N, 1.5 m/s, 2 h, 1050 °C and 0 wt.%) for wear rate, certain levels of all parameters (1000 m, 10 N, 1.5 m/s, 2 h, 1050 °C and 2.5 wt.%) for weight loss and 1000 m, 15 N, 1 m/s, 1 h, 1000 °C and 0 wt.% for the coefficient of friction. The comprehensive analysis of findings has practical significance and provides valuable information for a composite material from the production phase to the actual working conditions.

scholarly journals Influence of Beam Power on Young’s Modulus and Friction Coefficient of Ti–Ta Alloys Formed by Electron-Beam Surface Alloying

Metals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1246
Author(s):  
Stefan Valkov ◽  
Dimitar Dechev ◽  
Nikolay Ivanov ◽  
Ruslan Bezdushnyi ◽  
Maria Ormanova ◽  
...  
Keyword(s):  
Electron Beam ◽  
Young’S Modulus ◽  
Coefficient Of Friction ◽  
Young's Modulus ◽  
Beam Power ◽  
Surface Alloying ◽  
Surface Alloys ◽  
X Ray ◽  
The Coefficient Of Friction ◽  
Beam Surface

In this study, we present the results of Young’s modulus and coefficient of friction (COF) of Ti–Ta surface alloys formed by electron-beam surface alloying by a scanning electron beam. Ta films were deposited on the top of Ti substrates, and the specimens were then electron-beam surface alloyed, where the beam power was varied from 750 to 1750 W. The structure of the samples was characterized by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and X-ray diffraction (XRD). Young’s modulus was studied by a nanoindentation test. The coefficient of friction was studied by a micromechanical wear experiment. It was found that at 750 W, the Ta film remained undissolved on the top of the Ti, and no alloyed zone was observed. By an increase in the beam power to 1250 and 1750 W, a distinguished alloyed zone is formed, where it is much thicker in the case of 1750 W. The structure of the obtained surface alloys is in the form of double-phase α’and β. In both surface alloys formed by a beam power of 1250 and 1750 W, respectively, Young’s modulus decreases about two times due to different reasons: in the case of alloying by 1250 W, the observed drop is attributed to the larger amount of the β phase, while at 1750 W is it due to the weaker binding forces between the atoms. The results obtained for the COF show that the formation of the Ti–Ta surface alloy on the top of Ti substrate leads to a decrease in the coefficient of friction, where the effect is more pronounced in the case of the formation of Ti–Ta surface alloys by a beam power of 1250 W.

Reducing the Coefficient of Friction for Fast-Absorbing Gut Suture

2009 ◽  
Vol 35 (12) ◽  
pp. 2004 ◽  
Author(s):  
Jonathan Lee Bingham ◽  
Mariah R. Brown ◽  
Julian Ramsey Mellette
Keyword(s):  
Coefficient Of Friction ◽  
The Coefficient Of Friction

First Paper: Effect of Under-Lip Temperature on the Lubrication of Rotary Shaft Garter Spring Seals

1966 ◽  
Vol 181 (1) ◽  
pp. 185-190 ◽  
Author(s):  
D. J. Lines ◽  
J. M. Lawrie ◽  
J. P. O'Donoghue
Keyword(s):  
Coefficient Of Friction ◽  
Operating Temperature ◽  
Lubrication Theory ◽  
Fluid Film ◽  
Hydrodynamic Parameter ◽  
Accurate Knowledge ◽  
The Coefficient Of Friction ◽  
Surface Thermocouple ◽  
Sealing Mechanism ◽  
Film Lubrication

Although rotary shaft garter spring seals are widely used throughout industry, very little is known about the sealing mechanism of the lip-shaft interface. It is now generally accepted that some sort of fluid film separates the lip and the shaft. Previous workers have also postulated a relationship between the coefficient of friction and a non-dimensional hydrodynamic parameter, as in standard lubrication theory. This present paper clarifies this relationship, and shows that seals can also operate over the mixed friction, as well as the full film lubrication region. The results were obtained by accurate knowledge of the operating temperature under the sealing lip. Two types of surface thermocouple were developed to do this and these are described in full.

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