INVESTIGATION OF MICRO-PITS FORMATION ON BILLET SURFACES IN PLANE STRAIN EXTRUSION

2016 ◽  
Vol 78 (10-2) ◽  
Author(s):  
I. M. Izhan ◽  
S. Syahrullail ◽  
S. Y. Yong ◽  
M. A. Nurul
Keyword(s):  
Surface Roughness ◽  
Cross Section ◽  
Room Temperature ◽  
Palm Stearin ◽  
Mineral Oil ◽  
Tribological Performance ◽  
Work Piece ◽  
Half Angle ◽  
Plain Strain ◽  
Taper Die

Extrusion is a process of pushing a material through a die to yield a desired cross-section product. The application of surface texture has become well known for enhancing tribological performance. In this research, the effect of micro-pits embedded on a work piece lubricated with vegetable oil using plain strain extrusion were studied and compared with those seen with mineral-based oil lubricant. The experiments were conducted at room temperature (around 27℃). A taper die with a 60 die half-angle, with micro-pits array, was prepared. Test lubricants used were paraffinic mineral oil (PMO) VG460 and VG95 and refined, bleached and deodorized (RBD) palm stearin. The results were analysed to determine the extrusion load and the billet’s surface roughness and plastic deformation. RBD palm stearin was recorded as having the highest extrusion load (83.15 kN).

THE EFFECTS OF THE DIE HALF ANGLE OF TAPER DIE ON PLANE STRAIN EXTRUSION

2016 ◽  
Vol 78 (9-2) ◽  
Author(s):  
A. M. S. Zuan ◽  
S. Y. Yong ◽  
M. A. Nurul ◽  
S. Syahrullail ◽  
E. A. Rahim
Keyword(s):  
Surface Roughness ◽  
Relative Velocity ◽  
Palm Stearin ◽  
Extrusion Process ◽  
Mineral Oil ◽  
Comparison Study ◽  
Taper Angle ◽  
Workpiece Surface ◽  
Half Angle ◽  
Taper Die

In this research, a study of the effect of a die half angle on the extrusion process has been performed. The experiments were conducted at room temperature around 27 °C. Two types of taper die with different die half angles (45° and 60°) were prepared. The test lubricants used were paraffinic mineral oil VG460 and Refined, Bleached and Deodorized (RBD) Palm stearin. The material of the workpiece (billet) was annealed with A1100 aluminium. The experimental results were focused on the extrusion load, tool and workpiece surface roughness and plastic deformation of the workpiece. The resultant relative velocity was calculated using a visioplasticity method. The results shows that a taper angle of 60° recorded higher resultant relative velocity with a lower extrusion load and surface roughness compare to the taper angle of 45°. The comparison study between Paraffinic Mineral Oil and RBD Palm Stearin shows no significant effect in both taper angles tested.

Experimental Researching of Thermal - Assisted Milling with Induction on Surface Roughness of SKD11 Steel

2019 ◽  
Vol 889 ◽  
pp. 190-196
Author(s):  
Mac Thi Bich ◽  
Pham Thi Hoa ◽  
Banh Tien Long ◽  
Nguyen Duc Toan
Keyword(s):  
Surface Roughness ◽  
Room Temperature ◽  
Elevated Temperatures ◽  
End Milling ◽  
Heating Process ◽  
Work Piece ◽  
Technical Parameters ◽  
Roughness Model ◽  
Good Agreement

This paper presents experimental studied results about surface roughness during end milling SKD11 steel under room temperature and work-piece preheated condition. Conventional samples were first performed. The samples which are same technical parameters were then performed at elevated temperatures to evaluate effective of heating process on the surface roughness. Orthogonal array Taguchi method was used to experimental design. The results showed that the surface quality of product was significantly improved under thermal - assisted milling. The surface roughness model during machining at room and elevated temperatures were evaluated and showed a good agreement with result of experiments.

Study of Alternative Lubricants for Cold Extrusion Process of A1100 Pure Aluminum

2014 ◽  
Vol 71 (2) ◽  
Author(s):  
A. Nurul M. ◽  
Syahrullail S.
Keyword(s):  
Renewable Resources ◽  
Pure Aluminum ◽  
Cold Work ◽  
Palm Kernel ◽  
Palm Stearin ◽  
Mineral Oil ◽  
Cold Extrusion ◽  
Film Material ◽  
Ability To Act ◽  
Taper Die

Lubrication in metal forming process is very important to control wear and friction at the interface between interacting surfaces. Non-renewable resources, such as mineral oil are widely used since a beginning due to its ability to act as a supplier to the wearing contact which functions as a film material or sustains chemical transformation to become a film material. Since it is will not last for a few more decades, renewable resources had been studied in order to find an alternative lubricant with presents similar results in terms of extrusion load and product quality. Two renewable lubricants were analyzed (Palm Kernel and Palm Stearin) together with additive free paraffinic mineral oil VG460 will act as a comparison lubricant. The experiment used a cold work plane strain extrusion apparatus consisting of a pair of taper die and a symmetrical work piece (billet). The billet material was annealed pure aluminum A1100 with radius of 5mm at the deformation area. It was found that palm Palm Kernel and Palm Stearin performed slightly high extrusion load, however they show no severe wear on product surface. Based on the results, it is proven that renewable based lubricants can be considered as a substitute to common mineral based lubricants used in the industry.

scholarly journals OPTIMALISASI PROSES GERINDA UNTUK PERMUKAAN

2012 ◽  
Vol 11 (1) ◽  
pp. 26
Author(s):  
ARYA MAHENDRA SAKTI
Keyword(s):  
Surface Roughness ◽  
Room Temperature ◽  
Heat Energy ◽  
Work Piece ◽  
Air Cooling ◽  
Grinding Temperature ◽  
Cooling Method ◽  
Surface Work ◽  
Grinding Machine ◽  
Table Speed

Basically, surface grinding is mechanical process that result high temperature and chemicalreaction on surface work piece. On this process, the heat energy has been released along ofthe surface. A part of the energy would be transferred to chip and the other would be continuedto the environment by grinder and work piece. Use of coolant on the surface of the object will befunction as lubricant, which can reduce friction between grinder and the object. Moreover, ingrinding process, cooling can effect on temperature and surface roughness. This research usedfactorial design 2x3x3 to evaluate the effect some variables process such as table speed, depthof cut also cooling method on temperature and surface roughness. High pressure air and air inroom temperature are kinds of cooling method in the process, the result of experiment would beanalysis by ANAVA. The experiment shows that temperature in air cooling method it is lowerthan by air of room temperature cooling method. The surface roughness of the work piece in aircooling method is the lowest. The faster table speed of grinding machine caused that the lowerof the grinding temperature and the work piece surface roughness. Moreover, the higher depthof cut would cause the higher grinding temperature and surface roughness.

HREM observation of dislocations near room temperature fractures in silicon

1988 ◽  
Vol 46 ◽  
pp. 892-893
Author(s):  
M. H. Rhee ◽  
W. A. Coghlan
Keyword(s):  
Cross Section ◽  
Room Temperature ◽  
Single Crystal Silicon ◽  
Dislocation Nucleation ◽  
Back Side ◽  
Ion Milling ◽  
Crystal Silicon ◽  
Flat Surfaces ◽  
Induced Fractures ◽  
Vicker’S Microhardness

Silicon is believed to be an almost perfectly brittle material with cleavage occurring on {111} planes. In such a material at room temperature cleavage is expected to occur prior to any dislocation nucleation. This behavior suggests that cleavage fracture may be used to produce usable flat surfaces. Attempts to show this have failed. Such fractures produced in semiconductor silicon tend to occur on planes of variable orientation resulting in surfaces with a poor surface finish. In order to learn more about the mechanisms involved in fracture of silicon we began a HREM study of hardness indent induced fractures in thin samples of oxidized silicon.Samples of single crystal silicon were oxidized in air for 100 hours at 1000°C. Two pieces of this material were glued together and 500 μm thick cross-section samples were cut from the combined piece. The cross-section samples were indented using a Vicker's microhardness tester to produce cracks. The cracks in the samples were preserved by thinning from the back side using a combination of mechanical grinding and ion milling.

scholarly journals Photoelectric absorption cross section of silicon near the bandgap from room temperature to sub-Kelvin temperature

AIP Advances ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 025120
Author(s):  
C. Stanford ◽  
M. J. Wilson ◽  
B. Cabrera ◽  
M. Diamond ◽  
N. A. Kurinsky ◽  
...  
Keyword(s):  
Cross Section ◽  
Absorption Cross Section ◽  
Room Temperature ◽  
Absorption Cross ◽  
Photoelectric Absorption

scholarly journals Temperature-Dependent Stimulated Emission Cross-Section in Nd3+:YLF Crystal

Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 431
Author(s):  
Giorgio Turri ◽  
Scott Webster ◽  
Michael Bass ◽  
Alessandra Toncelli
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Room Temperature ◽  
Radiative Decay ◽  
Emission Cross Section ◽  
Spectroscopic Properties ◽  
Stimulated Emission ◽  
Different Temperatures ◽  
Stimulated Emission Cross Section ◽  
Semi Empirical

Spectroscopic properties of neodymium-doped yttrium lithium fluoride were measured at different temperatures from 35 K to 350 K in specimens with 1 at% Nd3+ concentration. The absorption spectrum was measured at room temperature from 400 to 900 nm. The decay dynamics of the 4F3/2 multiplet was investigated by measuring the fluorescence lifetime as a function of the sample temperature, and the radiative decay time was derived by extrapolation to 0 K. The stimulated-emission cross-sections of the transitions from the 4F3/2 to the 4I9/2, 4I11/2, and 4I13/2 levels were obtained from the fluorescence spectrum measured at different temperatures, using the Aull–Jenssen technique. The results show consistency with most results previously published at room temperature, extending them over a broader range of temperatures. A semi-empirical formula for the magnitude of the stimulated-emission cross-section as a function of temperature in the 250 K to 350 K temperature range, is presented for the most intense transitions to the 4I11/2 and 4I13/2 levels.

scholarly journals Experimental and Numerical Investigation of the ECAP Processed Copper: Microstructural Evolution, Crystallographic Texture and Hardness Homogeneity

Metals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 607
Author(s):  
A. I. Alateyah ◽  
Mohamed M. Z. Ahmed ◽  
Yasser Zedan ◽  
H. Abd El-Hafez ◽  
Majed O. Alawad ◽  
...  
Keyword(s):  
Grain Size ◽  
Equal Channel Angular Pressing ◽  
Cross Section ◽  
Room Temperature ◽  
Pure Copper ◽  
High Density ◽  
Ecap Processing ◽  
Heterogeneous Distribution ◽  
Angular Pressing ◽  
Average Grain Size

The current study presents a detailed investigation for the equal channel angular pressing of pure copper through two regimes. The first was equal channel angular pressing (ECAP) processing at room temperature and the second was ECAP processing at 200 °C for up to 4-passes of route Bc. The grain structure and texture was investigated using electron back scattering diffraction (EBSD) across the whole sample cross-section and also the hardness and the tensile properties. The microstructure obtained after 1-pass at room temperature revealed finer equiaxed grains of about 3.89 µm down to submicrons with a high density of twin compared to the starting material. Additionally, a notable increase in the low angle grain boundaries (LAGBs) density was observed. This microstructure was found to be homogenous through the sample cross section. Further straining up to 2-passes showed a significant reduction of the average grain size to 2.97 µm with observable heterogeneous distribution of grains size. On the other hand, increasing the strain up to 4-passes enhanced the homogeneity of grain size distribution. The texture after 4-passes resembled the simple shear texture with about 7 times random. Conducting the ECAP processing at 200 °C resulted in a severely deformed microstructure with the highest fraction of submicron grains and high density of substructures was also observed. ECAP processing through 4-passes at room temperature experienced a significant increase in both hardness and tensile strength up to 180% and 124%, respectively.

Modifications Required for Palm Oil to be Qualified as a Mechanical Lubricant

2019 ◽  
Vol 9 (1) ◽  
pp. 50-66
Author(s):  
Muhammad Sharil Yahayaa ◽  
Nurliyana Abdul Raof ◽  
Zulkifli Ibrahim ◽  
Azniza Ahmad ◽  
Chandima Gomes
Keyword(s):  
Palm Oil ◽  
Carbon Materials ◽  
Hexagonal Boron Nitride ◽  
Mineral Oil ◽  
Tribological Performance ◽  
Chemical Modifications ◽  
Environmental Friendly ◽  
Metal Metal ◽  
Nano Additives ◽  
Dialkyl Dithiophosphate

Adaptation of apt chemical modifications and incorporation of suitable additives, especially, nano-additives, could improve the properties of bio-lubricants derived from palm oil. This makes it one of the best alternatives to mineral oil lubricants. Possible chemical modifications are hydrogenation, esterification/ transesterification, epoxidation and metathesis. Feasible additives and nano-additives available in the market for minimizing the drawbacks of palm oil as a lubricant are ionic liquids, phosphorus, sulphur, zinc dialkyl dithiophosphate, metal, metal oxides, metal sulphides, carbonates, borates, carbon materials, organic materials, hexagonal boron nitride, alumina, CaO, CuO, ZnO, TiO2 and lanthanum borates. Few of them may not be environmental friendly. In line with market potentials and demand, it could be predicted that ROI of funding for the research and development of palm oil as a bio-lubricant may be significantly high. The study addresses tribological performance and properties, chemical modifications and formulation with additives of palm oil as a bio-lubricant.

Role of Rubber Stiffness and Surface Roughness in the Tribological Performance on Ice

2017 ◽  
Vol 61 (2) ◽  
pp. 295-303 ◽  
Author(s):  
Nihat A. Isitman ◽  
András Kriston ◽  
Tibor Fülöp
Keyword(s):  
Surface Roughness ◽  
Tribological Performance
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