Influence of Surface Textures During Metal Forming

2007 ◽  
Author(s):  
Pradeep L. Menezes ◽  
Kishore ◽  
Satish V. Kailas
Keyword(s):  
Flow Pattern ◽  
Coefficient Of Friction ◽  
Surface Texture ◽  
Metal Forming ◽  
Metal Flow ◽  
Steel Plates ◽  
Work Piece ◽  
Layer Formation ◽  
Transfer Layer ◽  
The Coefficient Of Friction

Friction plays an important role in metal forming processes. In the present investigation, various kinds of surface texture with varying roughness were produced on steel plates. Pins made of Al-8Mg alloy were then slid against the prepared steel plates using inclined pin-on-plate sliding tester to understand the role of surface texture of the harder surface and load on coefficient of friction and transfer layer formation under both dry and lubricated conditions. It was observed that both the coefficient of friction and transfer layer formation are highly dependent on the surface texture of harder counterface. Numerical analysis of simulated compression test, assigning different magnitude of coefficient of friction at different regions between the die and work piece, was carried out to understand the effect of friction on deformation and stress distribution. Results of simulation revealed that, owing to the difference in coefficient of friction, there is a difference in metal flow pattern. Both experimental and numerical results confirmed that the surface texture of the die surface and thus coefficient of friction directly affects the strain rate and flow pattern of the work-piece.

Influence of Inclination Angle and Machining Direction on Friction and Transfer Layer Formation

2010 ◽  
Vol 133 (1) ◽  
Author(s):  
Pradeep L. Menezes ◽  
Kishore ◽  
Satish V. Kailas ◽  
Michael R. Lovell
Keyword(s):  
Plane Strain ◽  
Coefficient Of Friction ◽  
Inclination Angle ◽  
Sliding Contact ◽  
Steel Plates ◽  
Layer Formation ◽  
Transfer Layer ◽  
Stick Slip ◽  
The Coefficient Of Friction ◽  
Slip Phenomenon

In the present investigation, unidirectional grinding marks were created on a set of steel plates. Sliding experiments were then conducted with the prepared steel plates using Al–Mg alloy pins and an inclined pin-on-plate sliding tester. The goals of the experiments were to ascertain the influence of inclination angle and grinding mark direction on friction and transfer layer formation during sliding contact. The inclination angle of the plate was held at 0.2 deg, 0.6 deg, 1 deg, 1.4 deg, 1.8 deg, 2.2 deg, and 2.6 deg in the tests. The pins were slid both perpendicular and parallel to the grinding marks direction. The experiments were conducted under both dry and lubricated conditions on each plate in an ambient environment. Results showed that the coefficient of friction and the formation of transfer layer depend on the grinding marks direction and inclination angle of the hard surfaces. For a given inclination angle, under both dry and lubricated conditions, the coefficient of friction and transfer layer formation were found to be greater when the pins slid perpendicular to the unidirectional grinding marks than when the pins slid parallel to the grinding marks. In addition, a stick-slip phenomenon was observed under lubricated conditions at the highest inclination angle for sliding perpendicular to the grinding marks direction. This phenomenon could be attributed to the extent of plane strain conditions taking place at the asperity level during sliding.

Response of Metals and Polymers During Sliding: Role of Surface Texture

2010 ◽  
Author(s):  
Pradeep L. Menezes ◽  
Kishore ◽  
Satish V. Kailas ◽  
Michael R. Lovell
Keyword(s):  
Surface Texture ◽  
Hardened Steel ◽  
Steel Plates ◽  
Layer Formation ◽  
Transfer Layer ◽  
Surface Textures ◽  
Microscope Images ◽  
The Coefficient Of Friction ◽  
Plate Apparatus

Surface texture influences friction during sliding. In the present investigation, experiments were conducted using an inclined pin-on-plate apparatus to study the tribological response of metals and polymers during sliding against various surface textures. In the experiments, metals (Pb and Sn) and polymers (PP and PVC) were used for the pin and hardened steel was used for the plate. Experiments were conducted under both dry and lubricated conditions in an ambient environment. Two surface parameters of the steel plates — roughness and texture — were varied in the experiments. Using scanning electron microscope images, the surfaces of both the plate and pin materials were examined to determine the transfer layer formation on the plate and the wear of the pins. Based on the experimental results, it was observed that the transfer layer formation and the coefficient of friction were controlled by the surface texture of the plates. Moreover, both polymers and metals exhibited similar frictional responses, but the metals had a significantly larger variation in friction with surface texture.

Influence of Inclination Angle and Surface Texture of the Plate on Friction and Transfer Layer Formation

2009 ◽  
Author(s):  
Pradeep L. Menezes ◽  
Kishore ◽  
Satish V. Kailas ◽  
Michael R. Lovell
Keyword(s):  
Coefficient Of Friction ◽  
Inclination Angle ◽  
Tilt Angle ◽  
Steel Plates ◽  
Hard Material ◽  
Layer Formation ◽  
Transfer Layer ◽  
Stick Slip ◽  
The Coefficient Of Friction ◽  
Slip Phenomenon

In the present investigation, unidirectional grinding marks were attained on the steel plates. Experiments were then conducted using pins of Al-Mg alloy against the prepared steel plates using an inclined pin-on-plate sliding tester. The goal of the research is to understand the influence of grinding mark direction and inclination angle of hard material on the friction and transfer layer formation during sliding. The inclination angle of the plate was held at 0.2°, 0.6°, 1°, 1.4°, 1.8°, 2.2° and 2.6° in the tests. The pins were slid both perpendicular and parallel to the grinding marks direction. Experiments were conducted under both dry and lubricated conditions on each plate in ambient environment. Results showed that the coefficient of friction and formation of transfer layer depend on the grinding marks direction and inclination angle of the hard surfaces. For a given inclination angle, the coefficient of friction and transfer layer formation were found to be more for the pins slid perpendicular to the unidirectional grinding marks when compared to parallel to the unidirectional grinding marks under both dry and lubricated conditions. The stick-slip phenomenon was observed only under lubricated conditions at the highest tilt angle for the sliding perpendicular to the grinding marks direction. These variations could be attributed to the extent of plane strain conditions taking place at the asperity level during sliding.

Studies on Friction and Transfer Layer Formation When Pure Magnesium Pins Slid at Various Numbers of Cycles on Steel Plates of Different Surface Texture

2010 ◽  
Author(s):  
Pradeep L. Menezes ◽  
Kishore ◽  
Satish V. Kailas ◽  
Michael R. Lovell
Keyword(s):  
Coefficient Of Friction ◽  
Surface Texture ◽  
Pure Magnesium ◽  
Steel Plates ◽  
Transfer Layer ◽  
Stick Slip ◽  
Die Surface ◽  
The Coefficient Of Friction ◽  
Dry Conditions ◽  
Number Of Cycles

In the present investigation, various kinds of textures (undirectional, 8-ground, and random,) were attained on a set of steel plate surfaces. The roughness of the textures was varied using different grits of emery papers or polishing powders. Pins made of pure magnesium were then slid against the steel plates at various numbers of cycles (1, 2, 6, 10 and 20) using an inclined pin-on-plate sliding apparatus. In the experiments, it was observed that the coefficient of friction and the formation of a transfer layer depended on the die surface textures under both dry and lubricated conditions. The coefficient of friction increased with number of cycles under dry conditions for all of the textures studied. Under lubricated conditions, however, the coefficient of friction decreased for unidirectional and 8-ground surfaces and increased for random surfaces with the number of cycles. A stick-slip phenomenon was observed under both dry and lubricated conditions. Occurrence of the stick slip behavior depended on the surface texture, the load and the number of cycles. The variation in the coefficient of friction under both dry and lubrication conditions was attributed to changes in the texture of the surfaces during sliding.

Influence of Alloying Element Addition on Friction and Transfer Layer Formation in Al-Mg System: Role of Surface Texture

2009 ◽  
Author(s):  
Pradeep L. Menezes ◽  
Kishore ◽  
Satish V. Kailas ◽  
Michael R. Lovell
Keyword(s):  
Coefficient Of Friction ◽  
Surface Texture ◽  
Steel Plates ◽  
Alloying Element ◽  
Transfer Layer ◽  
The Coefficient Of Friction ◽  
Element Addition ◽  
Primary Focus ◽  
Plate Apparatus

In the present investigation, sliding experiments were conducted using pins made of pure Al, Al-4Mg alloy, Al-8Mg alloy, Mg-8Al alloy and pure Mg against steel plates of various surface textures using a pin-on-plate apparatus under both dry and lubricated conditions. The primary focus of the study was to investigate the influence of alloying elements on the coefficient of friction and transfer later formation in Al-Mg systems. The morphologies of the worn surfaces of the pins and the formation of transfer layer on the counter surfaces were observed using a scanning electron microscope. It was observed for a given surface texture that the alloying element addition decreased the average coefficient of fiction to lower values under both dry and lubricated conditions. For a given material pair, the coefficient of friction and formation of transfer layer depend on the surface texture of the hard surfaces.

Studies on Friction and Formation of Transfer Layer in HCP Metals

2008 ◽  
Author(s):  
Pradeep L. Menezes ◽  
Kishore ◽  
Satish V. Kailas
Keyword(s):  
Coefficient Of Friction ◽  
Surface Texture ◽  
Soft Materials ◽  
Hard Material ◽  
Layer Formation ◽  
Ambient Conditions ◽  
Transfer Layer ◽  
Stick Slip ◽  
Stick Slip Motion ◽  
Slip Motion

Surface texture plays an important role as it predominantly controls the frictional behavior and transfer layer formation at the contacting surfaces. In the present investigation, basic studies were conducted using inclined pin-on-plate sliding tester to understand the role of surface texture of hard material on coefficient of friction and transfer layer formation when sliding against soft materials. HCP materials such as pure Mg and pure Zn were used as pins while 080 M40 steel was used as plate in the tests. Two surface parameters of steel plates — roughness and texture — were varied in the tests. Tests were conducted in ambient conditions under both dry and lubricated conditions. The morphologies of the worn surfaces of the pins and the formation of transfer layer on the counter surfaces were observed using a scanning electron microscope. It was observed for both the pin materials that the occurrence of stick-slip motion, the transfer layer formation and the value of coefficient of friction as well as its two components, namely, adhesion and plowing, depend primarily on surface texture. The effect of surface texture on coefficient of friction was attributed to the variation of plowing component of friction for different surfaces. Both the plowing component of friction and amplitude of stick-slip motion were highest for the surface texture that promotes plane strain conditions while these were lowest for the texture that favors plane stress conditions at the interface.

Studies on Friction and Formation of Transfer Layer in HCP Metals

2009 ◽  
Vol 131 (3) ◽  
Author(s):  
Pradeep L. Menezes ◽  
Kishore ◽  
Satish V. Kailas ◽  
Michael R. Lovell
Keyword(s):  
Surface Texture ◽  
Steel Plates ◽  
Ambient Conditions ◽  
Transfer Layer ◽  
Stick Slip ◽  
The Coefficient Of Friction ◽  
Hcp Materials ◽  
Stick Slip Motion ◽  
Slip Motion

Surface texture plays an important role in the frictional behavior and transfer layer formation of contacting surfaces. In the present investigation, basic experiments were conducted using an inclined pin-on-plate sliding apparatus to better understand the role of surface texture on the coefficient of friction and the formation of a transfer layer. In the experiments, soft HCP materials such as pure Mg and pure Zn were used for the pins and a hardened 080 M40 steel was used for the plate. Two surface parameters of the steel plates—roughness and texture—were varied in tests that were conducted at a sliding speed of 2 mm/s in ambient conditions under both dry and lubricated conditions. The morphologies of the worn surfaces of the pins and the formation of the transfer layer on the counter surfaces were observed using a scanning electron microscope. In the experiments, the occurrence of stick-slip motion, the formation of a transfer layer, and the value of friction were recorded. With respect to the friction, both adhesion and plowing components were analyzed. Based on the experimental results, the effect of surface texture on the friction was attributed to differences in the amount of plowing. Both the plowing component of friction and the amplitude of stick-slip motion were determined to increase surface textures that promote plane strain conditions and decrease the textures that favor plane stress conditions.

Correlating the Features of Topography to Friction by Sliding Experiments

2008 ◽  
Author(s):  
Anirudhan Pottirayil ◽  
Pradeep L. Menezes ◽  
Satish V. Kailas
Keyword(s):  
Sheet Metal ◽  
Coefficient Of Friction ◽  
Sheet Metal Forming ◽  
Metal Forming ◽  
Work Piece ◽  
Manufacturing Processes ◽  
Experimental Procedure ◽  
The Coefficient Of Friction ◽  
Soft Metal

Friction can influence the quality of the finished product to a large extent in certain manufacturing processes. Sheet metal forming is a particular case, where the friction between the hard-die and the relatively soft work-piece can be extremely important. Under such conditions, topography of the harder surface can influence the resistance to traction at the interface. This paper discusses about the correlation between certain features of the surface topography and coefficient of friction based on experiments involving sliding of a few soft metal pins against a harder material. A brief description of the experimental procedure and the analysis are presented. A hybrid parameter which encapsulates both the amplitude features as well as the relative packing of peaks is shown to correlate well with the coefficient of friction.

Effect of Roughness Parameter and Grinding Angle on Coefficient of Friction When Sliding of Al–Mg Alloy Over EN8 Steel

2006 ◽  
Vol 128 (4) ◽  
pp. 697-704 ◽  
Author(s):  
Pradeep L. Menezes ◽  
Kishore ◽  
Satish V. Kailas
Keyword(s):  
Coefficient Of Friction ◽  
Roughness Parameter ◽  
Mg Alloy ◽  
Layer Formation ◽  
Transfer Layer ◽  
Mating Surface ◽  
The Coefficient Of Friction ◽  
Scanning Electron Micrography ◽  
Angle Effect ◽  
Scratch Tests

Surface topography of harder mating surface plays an important role in metal forming operations as it predominantly controls the frictional behavior at the interface. In the present investigation, an inclined scratch tester was used to understand the effect of direction of surface grinding marks on interface friction and transfer layer formation. EN8 steel flats were ground to attain different surface roughnesses with unidirectional grinding marks. Al–Mg alloy pins were then scratched against the prepared EN8 steel flats. The grinding angle (angle between direction of scratch and grinding marks) was varied between 0 deg and 90 deg during the scratch tests. Scanning electron micrography of the contact surfaces revealed the transfer layer morphology. The coefficient of friction and transfer layer formation were observed to depend primarily on the direction of grinding marks of the harder mating surface, and independent of the surface roughness of harder mating surface. The grinding angle effect was attributed to the variation of plowing component of friction with grinding angle.

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