scholarly journals EXPERIMENTAL INVESTIGATION ON STRESS AND DIE-WALL FRICTIONAL CHARACTERISTICS OF METAL POWDER DURING HIGH-VELOCITY COMPACTION

2021 ◽  
Vol 55 (2) ◽  
pp. 163-170
Author(s):  
Wei Zhang ◽  
Kun Liu ◽  
Jian Zhou ◽  
Rongxin Chen ◽  
Ning Zhang ◽  
...  
Keyword(s):  
Metal Powder ◽  
Coefficient Of Friction ◽  
High Velocity ◽  
Side Wall ◽  
Repeated Loading ◽  
Testing Technology ◽  
The Coefficient Of Friction ◽  
Three Stages ◽  
High Velocity Compaction ◽  
The Impact

In this study, to evaluate the change in the stress and die-wall frictional characteristics during high-velocity compaction (HVC), a metal powder was subjected to HVC with a heavy hammer based on the stress-testing technology and Janssen-Walker model. The changes in the green density, stress characteristics and coefficients of friction at different impact heights were investigated. The density of green compacts increased with the increase in the impact height. The stress in the upper and lower punches and the die wall showed repeated loading and unloading. The coefficient of friction of the die wall underwent three stages and was related to powder densification. As the height position along the side wall was increased, the coefficient of friction increased gradually. With an increased impact height, the coefficient of friction increased significantly in the incomplete-molding stage but remained constant in the complete-molding stage. This work expands the theoretical basis of densification processing of a metal powder during HVC.

Characteristic Analysis of the Stress Propagation of Metal Powder in High Velocity Compaction Using DEM

2020 ◽  
Vol 89 (4) ◽  
pp. 044602
Author(s):  
Wei Zhang ◽  
Kun Liu ◽  
Jian Zhou ◽  
Rongxin Chen ◽  
Ning Zhang ◽  
...  
Keyword(s):  
Metal Powder ◽  
High Velocity ◽  
Characteristic Analysis ◽  
Stress Propagation ◽  
High Velocity Compaction

scholarly journals Effect of Iron Oxide Nanoparticles on the Properties of Water-Based Drilling Fluids

Energies ◽  
2020 ◽  
Vol 13 (24) ◽  
pp. 6718
Author(s):  
Muhammad Awais Ashfaq Alvi ◽  
Mesfin Belayneh ◽  
Sulalit Bandyopadhyay ◽  
Mona Wetrhus Minde
Keyword(s):  
Iron Oxide ◽  
Coefficient Of Friction ◽  
Drilling Fluid ◽  
Precipitation Method ◽  
Fluid Loss ◽  
Drilling Fluids ◽  
The Coefficient Of Friction ◽  
Filtrate Loss ◽  
Co Precipitation ◽  
The Impact

In recent years, several studies have indicated the impact of nanoparticles (NPs) on various properties (such as viscosity and fluid loss) of conventional drilling fluids. Our previous study with commercial iron oxide NPs indicated the potential of using NPs to improve the properties of a laboratory bentonite-based drilling fluid without barite. In the present work, iron oxide NPs have been synthesized using the co-precipitation method. The effect of these hydrophilic NPs has been evaluated in bentonite and KCl-based drilling fluids. Rheological properties at different temperatures, viscoelastic properties, lubricity, and filtrate loss were measured to study the effect of NPs on the base fluid. Also, elemental analysis of the filtrate and microscale analysis of the filter cake was performed. Results for bentonite-based fluid showed that 0.019 wt% (0.1 g) of NPs reduced the coefficient of friction by 47%, and 0.0095 wt% (0.05 g) of NPs reduced the fluid loss by 20%. Moreover, for KCl-based fluids, 0.019 wt% (0.1 g) of additive reduced the coefficient of friction by 45%, while higher concentration of 0.038 wt% (0.2 g) of NPs shows 14% reduction in the filtrate loss. Microscale analysis shows that presence of NPs in the cake structure produces a more compact and less porous structure. This study indicates that very small concentration of NPs can provide better performance for the drilling fluids. Additionally, results from this work indicate the ability of NPs to fine-tune the properties of drilling fluids.

scholarly journals Influences of the Air in Metal Powder High Velocity Compaction

2017 ◽  
Vol 95 ◽  
pp. 02001
Author(s):  
Jun Liu ◽  
Haifeng Hu ◽  
Xiaolong Luo
Keyword(s):  
Metal Powder ◽  
High Velocity ◽  
High Velocity Compaction

Dependence of the Coefficient of Friction on the Sliding Conditions in the High Velocity Range

1999 ◽  
Vol 121 (1) ◽  
pp. 35-41 ◽  
Author(s):  
A. Molinari ◽  
Y. Estrin ◽  
S. Mercier
Keyword(s):  
Coefficient Of Friction ◽  
High Velocity ◽  
Numerical Solutions ◽  
Constitutive Relations ◽  
Shear Banding ◽  
Normal Pressure ◽  
Adiabatic Shear ◽  
Velocity Range ◽  
Adiabatic Shear Banding ◽  
The Coefficient Of Friction

The velocity, normal pressure, and slider size dependence of the coefficient of dry friction of metals in the range of high sliding velocities (V ≥ 1 m/s) is investigated theoretically. Failure of the adhesive junctions by adiabatic shear banding is considered as the underlying process. The concept of asperity shearing by the adiabatic shear banding mechanism represents a new approach to unlubricated high velocity friction. Analytical solutions of a coupled thermomechanical problem are given for two constitutive relations. Numerical solutions for steel-on-steel friction showing a decrease of the coefficient of friction with the sliding velocity for different normal pressures are presented. The model is considered to be adequate in the velocity range of 1–10 m/s where friction enhanced oxidation or surface melting are believed not to interfere with the asperity shearing process.

Coefficient of Friction for Aluminum Alloy Sheet in Contact with Polyurethane Rubber

2010 ◽  
Vol 26-28 ◽  
pp. 320-325 ◽  
Author(s):  
Li Li Wang ◽  
Dong Sheng Li ◽  
Xiao Qiang Li ◽  
Liang Wang ◽  
Wei Jun Yang
Keyword(s):  
Aluminum Alloy ◽  
Coefficient Of Friction ◽  
Normal Load ◽  
Orthogonal Experimental Design ◽  
Sliding Velocity ◽  
Stretch Forming ◽  
Forming Process ◽  
Alloy Material ◽  
The Coefficient Of Friction ◽  
The Impact

Stretch forming process of aircraft skin over reconfigurable compliant tooling is a new technology in skin manufacturing. During this process, the coefficient of friction is important for modeling accurately the process of stretch forming. The objective of this research is to measure the coefficient of friction for aluminum alloy in contact with polyurethane rubber in reciprocal sliding. An orthogonal experimental design was used to reveal the impact of four factors on the coefficient of friction, including lubrication, normal load, aluminum alloy material and sliding velocity. It is shown that lubrication is a major factor, sliding velocity is a minor factor. The influence of normal pressure is less than sliding velocity and the influence of aluminum alloy material is not very obvious. Finally, based on the experiment results, the selections of lubricant and stretching velocity are discussed in order to improve the process of stretch forming.

scholarly journals A Control Method of High Impact Energy and Cosimulation in Powder High-Velocity Compaction

2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Dongdong You ◽  
Dehui Liu ◽  
Hangjian Guan ◽  
Qingyun Huang ◽  
Zhiyu Xiao ◽  
...  
Keyword(s):  
Impact Energy ◽  
High Velocity ◽  
Mechanical Energy ◽  
High Impact ◽  
Experimental Results ◽  
Hydraulic Control ◽  
Green Density ◽  
High Impact Energy ◽  
High Velocity Compaction ◽  
The Impact

To enhance the impact energy of powder high-velocity compaction (HVC) and thus improve the green density and mechanical properties of the resulting compacts, a mechanical energy storage method using combination disc springs is proposed. The high impact energy is achieved by modifying existing equipment, and the hydraulic control system is developed to implement the automatic control of the energy produced from the disc springs. An interdisciplinary cosimulation platform is established using the ADAMS, AMESim, and LabVIEW software packages to perform the interactive control of the simulation process and the real-time feedback of the simulation results. A mechanical-hydraulic cosimulation of the energy control virtual prototype of the testing machine is conducted using this platform. The influence of the impact energy on the green density is studied according to the HVC experimental results of the iron-based powders, and then, the green compact with the higher relative density is produced. The experimental results indicate that the energy enhancement method using the combination disc springs is reasonable and that the hydraulic control scheme is reliable.

High Velocity Compaction : Overview of Materials, Applications and Potential

2007 ◽  
Vol 534-536 ◽  
pp. 293-296 ◽  
Author(s):  
Florence Dore ◽  
Ludovic Lazzarotto ◽  
Stephane Bourdin
Keyword(s):  
Impact Velocity ◽  
High Velocity ◽  
New Technology ◽  
Machining Process ◽  
Powder Materials ◽  
Component Shape ◽  
High Velocity Compaction ◽  
Set Up ◽  
The Impact ◽  
Sintered Materials

Since 2000, CETIM has been equipped with a High Velocity Press that can deliver up to 5 shots per second with each blow accurately set up (up to 20000J) thanks to the impact velocity regulation (up to 11m.s-1). Through different projects, CETIM and its scientific and industrial partners have evaluated the potential of this new technology in terms of materials and component shape. Various kinds of powder materials were studied: metals, ceramics and polymers. The HVC process was used with success to manufacture gears, large parts and multilevel components. More than, the green machining process that enables shapes to be produced that would otherwise be impossible to compact is improved by the high density of HVC parts and it is also an opportunity to produce components with very hard sintered materials.

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