Tribological Testing of Graphite and Boron Nitride Lubricant Formulations for High Temperature Aluminum Sheet Forming Processes

2007 ◽  
Author(s):  
M. David Hanna ◽  
Paul E. Krajewsk ◽  
James G. Schroth
Keyword(s):  
High Temperature ◽  
Boron Nitride ◽  
Superplastic Forming ◽  
Solid Lubricants ◽  
Sheet Forming ◽  
Aluminum Sheet ◽  
Plastic Forming ◽  
Quick Plastic Forming ◽  
Performance And Evaluation

The tribological behavior of AA5083 aluminum sheet sliding against tool steel impacts the quality of components manufactured with the elevated temperature metal forming processes such as Quick Plastic Forming (QPF), Superplastic Forming (SPF), or warm forming. This study focuses on the tribological performance and evaluation of alternative solid lubricants using a flat-on-flat tribo-tester to simulate sheet forming at high temperature applications. Improved lubricant formulations containing boron nitride with graphite additions were found to enhance lubricity while maintaining good adherence to the surface of the aluminum blank at a temperature of 450°C.

The Effect of Boron Nitride Lubricant Thickness and Steel Surface Condition on Tribological Behavior of P20 Steel/5083 Aluminum Sliding Pairs at High Temperature

2008 ◽  
Author(s):  
M. David Hanna ◽  
Vjekoslav Franetovic
Keyword(s):  
Boron Nitride ◽  
Tribological Behavior ◽  
Surface Condition ◽  
Lubricant Thickness ◽  
Test Technique ◽  
Uncoated Steel ◽  
Plastic Forming ◽  
Quick Plastic Forming ◽  
Speed Method

The tribological behavior of AA5083 aluminum sheet sliding against tool steel impacts the quality of components manufactured with the Quick Plastic Forming (QPF) process. The effect of boron nitride lubricant thickness on the tribological performance of different coated steel/AA5083 pairs utilizing a recently developed reciprocating flat-on-flat tribological test technique was investigated. In most cases of coated and uncoated steel, the time-to-contact increased by a factor of ten when the BN thickness was increased from 8.4 μm to 14.5 μm. The tribological tests with a low sliding speed method (0.1 Hz) confirmed the previous observations conducted at 0.5 Hz in which nitrocarburizing of the tool surface decreased adhesion of aluminum to the steel during sliding contact.

Hot Tensile Behavior of Superplastic and Commercial AA5083 Sheets at High Temperature and Strain Rate

2013 ◽  
Vol 554-557 ◽  
pp. 63-70 ◽  
Author(s):  
Stefania Bruschi ◽  
Andrea Ghiotti ◽  
Francesco Michieletto
Keyword(s):  
High Temperature ◽  
Strain Rate ◽  
Automotive Industry ◽  
Hot Stamping ◽  
Superplastic Forming ◽  
Tensile Behavior ◽  
Tensile Behaviour ◽  
Fine Grained ◽  
Plastic Forming ◽  
Quick Plastic Forming

Since the last two decades, the automotive industry has dedicated an increasing attention to the manufacturing of sheet components made of high-resistant aluminium alloys; the superplastic AA5083 grade is currently utilized in both the conventional superplastic forming and the recently patented quick plastic forming, which assures higher productivity compared to that of superplastic forming, while the commercial AA5083 grade is rarely employed. The objective of the paper is to compare the hot tensile behaviour of commercial and fine-grained AA5083 sheets when processed at high temperature and strain rate, which are typical of hot stamping processes. The results are presented and commented in terms of flow stress, anisotropy, strain at failure, microstructural and hardness features as a function of temperature and strain rate. On the basis of the obtained results, the set of optimal forming conditions for the two grades is identified.

A New Technique for the Investigation of Tribological Behavior of Sliding Pairs Used in Hot Forming Processes

2008 ◽  
Author(s):  
Vjekoslav Franetovic
Keyword(s):  
Tribological Behavior ◽  
Hot Forming ◽  
New Technique ◽  
Aluminum Sheet ◽  
Forming Process ◽  
The Real ◽  
Plastic Forming ◽  
Quick Plastic Forming ◽  
A New Technique ◽  
Interacting Surfaces

Hot forming of aluminum sheet is highly influenced by the tribological behavior of the interacting surfaces of sliding pairs. Here we describe a new technique to investigate tribo-pair candidates for Quick Plastic Forming (QPF) and warm forming processes. This technique represents a bench type simulation of the real forming process where the sheet and tool interact by sliding against each other in a single motion (slide/stroke).

Sheet Orientation Effects on the Hot Formability Limits of Lightweight Alloys

2011 ◽  
Vol 133 (6) ◽  
Author(s):  
Fadi Abu-Farha ◽  
Louis G. Hector
Keyword(s):  
Rolling Direction ◽  
Superplastic Forming ◽  
Strain Ratio ◽  
Forming Limit ◽  
Specific Strain ◽  
Plastic Forming ◽  
Lightweight Alloys ◽  
Quick Plastic Forming ◽  
The Relationship ◽  
5083 Aluminum Alloy

The formability curves of AZ31B magnesium and 5083 aluminum alloy sheets were constructed using the pneumatic stretching test at two different sets of forming conditions. The test best resembles the conditions encountered in actual hydro/pneumatic forming operations, such as the superplastic forming (SPF) and quick plastic forming (QPF) techniques. Sheet samples were deformed at (400 °C and 1 × 10−3 s−1) and (450 °C and 5 × 10−3 s−1), by free pneumatic bulging into a set of progressive elliptical die inserts. The material in each of the formed domes was forced to undergo biaxial stretching at a specific strain ratio, which is simply controlled by the geometry (aspect ratio) of the selected die insert. Material deformation was quantified using circle grid analysis (CGA), and the recorded planar strains were used to construct the forming limit curves of the two alloys. The aforementioned was carried out with the sheet oriented either along or across the direction of major strains in order to establish the relationship between the material’s rolling direction and the corresponding limiting strains. Great disparities in limiting strains were found in the two orientations for both alloys; hence, a “composite FLD” is introduced as an improved means for characterizing material formability limits.

Grinding Capability of the Indigenous Polymer-Based Solid Lubricant Coating Wheels Used in Dry Grinding

2011 ◽  
Vol 697-698 ◽  
pp. 80-83
Author(s):  
L.Y. Ding ◽  
Hong Hua Su ◽  
H.J. Xu ◽  
M. Fan
Keyword(s):  
Boron Nitride ◽  
Surface Quality ◽  
Solid Lubricant ◽  
Hexagonal Boron Nitride ◽  
Solid Lubricants ◽  
Grinding Temperature ◽  
Solid Lubricant Coating ◽  
Lubricant Coating ◽  
Dry Grinding

It is essential to control the heat generated in the cutting zone in order to ensure the workpiece quality after grinding. This article deals with an investigation in using graphite and hexagonal boron nitride as solid lubricants to reduce friction and thereby improve the surface integrity of Ti-6Al-4V alloy. The polymer-based solid lubricant coating wheels have been prepared. Grinding experiments have been conducted to study the effect of the graphite and hexagonal boron nitride lubricants on the grinding temperature and the surface quality of the workpiece while grinding Ti-6Al-4V. Results indicate that there is a considerable improvement in the performance of grinding Ti-6Al-4V using graphite and hexagonal boron nitride as solid lubricants in dry grinding in terms of grinding temperature and surface quality of the work piece. The indigenous polymer-based solid lubricant coatings are effective in dry grinding.

High-Temperature Forming of a Vehicle Closure Component in Fine-Grained Aluminum Alloy AA5083: Finite Element Simulations and Experiments

2010 ◽  
Vol 433 ◽  
pp. 197-209 ◽  
Author(s):  
Louis G. Hector ◽  
Paul E. Krajewski ◽  
Eric M. Taleff ◽  
Jon T. Carter
Keyword(s):  
Finite Element ◽  
High Temperature ◽  
Sheet Thickness ◽  
Alloy Sheet ◽  
Forming Process ◽  
Material Models ◽  
Fine Grained ◽  
Plastic Forming ◽  
Quick Plastic Forming ◽  
Forming Defects

Fine-grained AA5083 aluminum-magnesium alloy sheet can be formed into complex closure components with the Quick Plastic Forming process at high temperature (450oC). Material models that account for both the deformation mechanisms active during forming and the effect of stress state on material response are required to accurately predict final sheet thickness profiles, the locations of potential forming defects and forming cycle time. This study compares Finite Element (FE) predictions for forming of an automobile decklid inner panel in fine-grained AA5083 using two different material models. These are: the no-threshold, two-mechanism (NTTM) model and the Zhao. The effect of sheet/die friction is evaluated with five different sheet/die friction coefficients. Comparisons of predicted sheet thickness profiles with those obtained from a formed AA5083 panel shows that the NTTM model provides the most accurate predictions.

Forming Limit Diagrams for AA5083 under SPF and QPF Conditions

2007 ◽  
Vol 551-552 ◽  
pp. 129-134 ◽  
Author(s):  
Mary Anne Kulas ◽  
Paul E. Krajewski ◽  
John R. Bradley ◽  
Eric M. Taleff
Keyword(s):  
Strain Rate ◽  
Plane Strain ◽  
Superplastic Forming ◽  
Forming Limit ◽  
Forming Limit Diagrams ◽  
Commercial Grade ◽  
Bulge Testing ◽  
Macroscopic Fracture ◽  
Plastic Forming ◽  
Quick Plastic Forming

Forming Limit Diagrams (FLD’s) for AA5083 aluminum sheet were established under both Superplastic Forming (SPF) and Quick Plastic Forming (QPF) conditions. SPF conditions consisted of a strain rate of 0.0001/s at 500°C, while QPF conditions consisted of a strain rate of 0.01/s at 450°C. The forming limit diagrams were generated using uniaxial tension, biaxial bulge, and plane strain bulge testing. Forming limits were defined using two criteria: (1) macroscopic fracture and (2) greater than 2% cavitation. Very little difference was observed between the plane strain limits in the SPF and QPF conditions indicating comparable formability between the two processes with a commercial grade AA5083 material.

Improved Tribological Performance of Tribo-Pairs by Optimization of Sliding Speed: Implications for Hot Forming Processes

2008 ◽  
Author(s):  
Vjekoslav Franetovic
Keyword(s):  
Cost Effectiveness ◽  
Friction Coefficient ◽  
Tribological Performance ◽  
Hot Forming ◽  
Sliding Speed ◽  
Plastic Forming ◽  
Quick Plastic Forming ◽  
Aluminum Panels ◽  
The Cost

The tribology of hot forming processes is highly critical for the quality of formed aluminum panels and the cost-effectiveness of hot forming. In this report a flat-on-flat experimental technique for tribological evaluation of a single stroke was used to investigate the effect of sliding speed on the operative friction coefficient (FC) and tribological failure of the tribo-pairs used in Quick Plastic Forming (QPF) and warm forming processes.

INFLUENCE OF FORCED CONVECTION IN LIQUID INSIDE THE TIN ON DURATION OF STERILIZATION IN THE COURSE OF FISH PROCESSING

2017 ◽  
pp. 137-144
Author(s):  
Gennadiy Valentinovich Alexeev ◽  
Elena Igorevna Verboloz
Keyword(s):  
High Temperature ◽  
Liquid Phase ◽  
Forced Convection ◽  
Thermal Process ◽  
Processing Time ◽  
Fish Processing ◽  
Study Results ◽  
Equipment Modernization ◽  
Bottom To Top

The article focuses on the process of intensive mixing of liquid phase in the tin during high-temperature sterilization, i.e. sterilization when temperature of the heat carrier reaches 150-160°C. It has been stated that for intensification of the thermal process during sterilization of tinned fish with liquid filling it is preferable to turn a tin from bottom to top. This operation helps to increase the driving power of the process and to shorten warming time. Besides, high-temperature sterilization carried out according to experimental modes, where the number of tin turnovers is calculated, greatly shortens processing time and improves quality of the product. In this case there is no superheating, all tins are evenly heated. The study results will contribute to equipment modernization and to preserving valuable food qualities.

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