Hydrostatic Extrusion With Controlled Follower Block Clearance

1975 ◽  
Vol 97 (1) ◽  
pp. 25-31 ◽  
Author(s):  
K. M. Kulkarni ◽  
J. A. Schey
Keyword(s):  
Ambient Temperature ◽  
Surface Finish ◽  
Extrusion Ratio ◽  
Hydrostatic Extrusion ◽  
Extrusion Force ◽  
Processing Conditions ◽  
Surface Processing ◽  
Specimen Diameter ◽  
Lubricant Viscosity ◽  
Breakthrough Pressure

Hydrostatic extrusion of annealed 1100 aluminum was investigated experimentally at ambient temperature. The principal variables studied were lubricant viscosity which was varied from less than 100 to over 76,000 SUS at 100 deg F and the diametral clearance between the follower block and the extrusion cylinder which ranged from 0.0005 to 0.0030 in. for the 1.026 in. dia. cylinder. The specimen diameter was 0.97 or 1.00 in. corresponding to an extrusion ratio of 4.75 or 5.00, respectively. The included die angle was either 60 deg or 90 deg. The results show that with a proper combination of the lubricant viscosity and the follower block clearance, hydrostatic extrusion can be accomplished without the necessity of any sealing of the container on the follower block side. The optimum clearance for minimum breakthrough pressure increases as the lubricant viscosity increases. The extrusion force increases with die angle. The paper discusses the various factors that affect the magnitude of the breakthrough pressure and the occasional uneven bamboo-type appearance of the surface. Processing conditions must be selected carefully since the lowest extrusion force does not necessarily lead to a product with the best surface finish.

The effect of surface processing conditions on the junction properties of CuIn[sub x]Ga[sub 1−x]Se[sub 2] solar cells

1997 ◽  
Author(s):  
S. Zafar ◽  
J. D’Amico ◽  
S. Karthikeyan ◽  
R. Narayanaswamy ◽  
P. Panse ◽  
...  
Keyword(s):  
Solar Cells ◽  
Processing Conditions ◽  
Surface Processing ◽  
Effect Of Surface

Investigation of Friction Using Non-Newtonian Lubricant Model in Hydrostatic Extrusion of Tungsten Alloy

2015 ◽  
Vol 813-814 ◽  
pp. 541-549
Author(s):  
Pankaj Tomar
Keyword(s):  
Extrusion Process ◽  
Friction Model ◽  
Hydrostatic Extrusion ◽  
Work Zone ◽  
Tungsten Alloy ◽  
Contact Friction ◽  
Hard Material ◽  
Lubricating Layer ◽  
Lubricant Viscosity

Friction at die/billet interface is a complex phenomenon affected by various operating and process parameters in metal forming industries. In presence of lubricating layer at the interfacial contact friction effect is reduced and enhances tool life and surface quality of product. The lubricant viscosity is strongly dependent on pressure and temperature during deformation of hard material and an accurate prediction of lubricants viscosity leads to realistic results in the work zone. Therefore, the paper incorporates numerical simulation of friction at the die/billet interface in hydrostatic extrusion of tungsten alloy 93W for three different lubricants whose rheology is represented by a Non-Newtonian friction model. The billet heating effect is incorporated in the investigation and results show that the co-efficient of friction varies in a range (0.058 to 0.062) along the work zone for various lubricating conditions in hydrostatic extrusion process.

The Microstructures and Mechanical Properties of Hot-Processed Magnesium Casting Alloys

2006 ◽  
Vol 503-504 ◽  
pp. 775-780 ◽  
Author(s):  
Takeshi Yamaguchi ◽  
Tadayoshi Tsukeda ◽  
Ken Saito ◽  
Yoshihito Kawamura
Keyword(s):  
Mechanical Properties ◽  
Magnesium Alloy ◽  
Extrusion Direction ◽  
High Strength ◽  
Extrusion Ratio ◽  
Extrusion Temperature ◽  
Tensile Yield Strength ◽  
Extrusion Force ◽  
Casting Alloys ◽  
Magnesium Casting

In order to make the effect of processing clear, AM50A magnesium casting alloys were extruded at various extrusion conditions such as extrusion temperature and extrusion ratio. The mechanical properties of AM50A alloy increased with decreasing extrusion temperature. Tensile yield strength and tensile strength of extruded AM50A alloy were 389MPa and 420MPa respectively when the extrusion temperature was 348K. The microstructure of the extruded magnesium alloy showed large grains stretched to the extrusion direction and fine recrystallized grains. Decreased extrusion temperature resulted in improved strength and decreased elongation with increasing of the degree of work hardens and extrusion force. When the extrusion ratio is high, improvement of strength is prevented by rycrystallization and it was observed as crystal orientation by XRD. The elongation of the extrusion increased with the recrystallization of grains. Every magnesium alloy extruded at low temperature has high strength.

IN VITRO EVALUATION OF PROCESSING CONDITIONS FOR THERMOAMMONIATION OF CORN STOVER

1979 ◽  
Vol 59 (4) ◽  
pp. 813-816 ◽  
Author(s):  
U. I. OJI ◽  
D. N. MOWAT ◽  
J. E. WINCH
Keyword(s):  
Moisture Content ◽  
Ambient Temperature ◽  
Corn Stover ◽  
Elevated Temperatures ◽  
In Vitro Digestion ◽  
Processing Conditions ◽  
In Vitro Evaluation ◽  
Optimum Processing

Thermoammoniation of corn stover increased rate and extent of in vitro digestion over ammoniation at ambient temperature. Increasing moisture content up to at least 60% improved response to ammoniation. Processing at elevated temperatures did not reduce the amount of NH3 required. Optimum processing conditions appear to be 3 to 4% NH3, 60% H2O and 90 °C for 6 to 12 h.

SIMULATION OF FINAL DIRECT EXTRUSION STAGE FOR LARGE RODS WITH LOW EXTRUSION RATIO

2018 ◽  
pp. 48-55
Author(s):  
V. R. Kargin ◽  
A. Yu. Deryabin
Keyword(s):  
Defect Formation ◽  
Cone Angle ◽  
Metal Flow ◽  
Joint Effect ◽  
Extrusion Ratio ◽  
Contact Friction ◽  
Extrusion Force ◽  
Direct Extrusion ◽  
Negative Effect ◽  
Edge Temperature

The direct extrusion of large 7075 alloy bars 188, 214, 252, 283, 326, 560 mm in diameter was simulated with 0 and 0,5 friction coefficients, 80° and 90° die cone angles from the 800 mm diameter container at the 200 MN press using the DEFORM-2D software package. It provided the distribution of metal flow radial velocities on the dummy block working surface versus the contact friction value, die cone angle and extrusion ratio factor at the main and final stages of extrusion. Butt-end height at the beginning of back-end extrusion defect formation was taken equal to a distance between the dummy block plane and the plane of extruded metal feeding into flat or cone die openings. The joint effect of the extrusion ratio factor, friction coefficient and die cone angle on the butt-end height, extrusion force, deformation and stress intensity factors, and die opening edge temperature was studied. Numerical experiments were performed based on the 23 complete factorial design for the following parameter variability intervals: Х1 = 3÷9, Х2 = 0÷0,5, Х3 = 80÷90°. Friction between the tool and the blank at the final extrusion stage has a negative effect due to a noticeable radial velocity reduction. This leads to the earlier initiation of central back-end extrusion defect formation. Extrusion into the conical die and increasing the extrusion ratio factor, on the contrary, speeds up radial flow velocity and ensures that the back-end extrusion defect starts forming later. The main factor that determines butt-end height is the extrusion ratio factor. A mathematical model is proposed to select the butt-end thickness for specific conditions of extruding large bars with low extrusion ratios.

The Surface Deformation of Aluminum Compressed With Viscous Lubricants

1974 ◽  
Vol 96 (4) ◽  
pp. 591-594 ◽  
Author(s):  
D. D. Ratnagar ◽  
H. S. Cheng ◽  
J. A. Schey
Keyword(s):  
Aluminum Alloy ◽  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Surface Finish ◽  
Surface Deformation ◽  
Surface Roughening ◽  
6061 Aluminum Alloy ◽  
Clear Delineation ◽  
Lubricant Viscosity ◽  
Scanning Electron

The influences of lubricant viscosity and loading velocity on the surface finish of plastically compressed 6061 aluminum alloy cylinders were studied. Specimens with polished end faces were subjected to compression between two flat, chromium plated dies, with lubricants of a viscosity ranging from 42 cp to 1207 cp at 38 deg C. The deformed surfaces were studied under a scanning electron microscope and by stylus tracings and CLA readings. With the lighter lubricants surface roughening resulted from preferential yielding leading to a clear delineation of grain boundaries and slip lines. With the heavier lubricants, localized “hydrodynamic pockets” formed in addition to the above features. The depth of pockets increased with viscosity and/or velocity.

The Effect of Lubricant Viscosity in Cold Work Forward Extrusion

2014 ◽  
Vol 554 ◽  
pp. 291-295
Author(s):  
Samion Syahrullail ◽  
Shunpei Kamitani ◽  
Kenji Nakanishi
Keyword(s):  
Sliding Friction ◽  
Pure Aluminum ◽  
Cold Work ◽  
Metal Flow ◽  
Extrusion Process ◽  
High Viscosity ◽  
Extrusion Force ◽  
Workpiece Surface ◽  
Forward Extrusion ◽  
Lubricant Viscosity

In cold work extrusion, lubricants play an important role in lubricating the tool and workpiece surfaces, preventing metal-to-metal contact and reducing sliding friction, so that the workpiece can be extruded smoothly without severe wear due to lubricant starvation. In this paper, the influence of lubricant viscosity in cold work forward extrusion was investigated. The lubricants were additive-free, paraffinic mineral oil, which may have low, medium or high viscosity. The workpiece material was pure aluminum A1100, extruded with extrusion ratio of 3. The analysis focused on extrusion force, workpiece surface roughness after the extrusion process and the metal flow in the deformation zone of the workpiece. Using the visioplasticity method, the sliding velocity was calculated from the metal flow. Results showed that, the higher the lubricant viscosity, the lower the extrusion force generated. However, a high-viscosity lubricant produces coarser workpiece surface conditions after the extrusion process.

scholarly journals The Application of Taguchi Approach to Optimise the Processing Conditions on Bonnet Polishing of CoCr

2011 ◽  
Vol 496 ◽  
pp. 235-240 ◽  
Author(s):  
Sheng Yue Zeng ◽  
Liam Blunt ◽  
Xiang Qian Jiang
Keyword(s):  
Surface Roughness ◽  
Optimal Condition ◽  
Process Optimization ◽  
Surface Finish ◽  
Taguchi Approach ◽  
Processing Conditions ◽  
Optimal Processing ◽  
Tool Offset ◽  
Cocr Alloy ◽  
Diamond Paste

This paper applied the Taguchi approach to investigate the effects of polishing parameters to obtain the optimal processing conditions for CoCr alloy polishing using a multiaxis CNC controlled corrective polishing machine. The polishing medium used was 1m diamond paste with a Microcloth(polishing cloth). Surface finish parameter Sa was chosen as the criterion for process optimization. The experimental results indicate that the optimal polishing conditions for CoCr alloy polishing is 50 precess angle, 800 rpm head speed, 0.2mm tool offset and 1.5 bar tool pressure. With this optimal condition, a confirmatory experiment was conducted. The surface roughness Sa reduced from an initial 24nm to 7nm and reduction ratio was 70.8% which was very close to the estimated ratio of 64%.

Researches on a Composite Extrusion Approach Based on FEM Method and Experiments

2011 ◽  
Vol 686 ◽  
pp. 305-309 ◽  
Author(s):  
Ding Fei Zhang ◽  
Jun Ping Zhang ◽  
Hong Jun Hu
Keyword(s):  
Mechanical Properties ◽  
Element Model ◽  
Az31 Alloy ◽  
Extrusion Ratio ◽  
Extrusion Force ◽  
Direct Extrusion ◽  
Fem Method ◽  
Shear Process ◽  
Different Temperatures ◽  
Microstructures And Mechanical Properties

This paper deals with a finite element model (FEM) for the extrusion of AZ31 alloy and extrusion experiments at different temperatures. The simulation is utilized to predict the extrusion force and strain at different temperatures. ES (extrusion-shear) process and direct extrusion are investigated at 370, 400 and 420°C to discuss the effects of different temperatures on the microstructures and mechanical properties with the extrusion ratio of 11.56. The simulation results obtained show that the extrusion force of ES process is much larger than direct extrusion because of the two corners. ES process could effectively refine the grains, especially the microstructure of the central region compared with direct extrusion. The bar extruded at 370°C shows the best microstructures and mechanical properties.

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