Sponsered by: SMD Non-Ferrous Metals Committee and Light Metals Division
Program Organizer: Professor James G. Morris, Chemical & Materials Engineering, Director, Light Metals Research Labs., University of Kentucky, Lexington, KY 40506
Wednesday, AM Room: A2-3
February 6, 1996 Location: Anaheim Convention Center
Session Chairperson: Gyan Jha, ARCO Aluminum, Inc., 2900 First National Tower, P.O. Box 32860, Louisville, KY 40232
8:30 am Invited
THE INFLUENCE OF ALLOYING AND PROCESSING ON THE DEEP DRAWING PERFORMANCE OF FOOD CAN MATERIALS: S.E. Naess, Hydro Aluminium, N- 3080 Holmestrand, Norway
The effect of some variations of processing parameters as well as alloy selection on the stretch formability and earing behaviour are illustrated by using industrially fabricated cans. Stretch forming fracture problems may be experienced in the upper part of the corner region in the second step of two- step deep-drawn conical rectangular cans. Of the two alternative alloys, AA3005 and AA5050A, the problem was confined to the latter, even though this alloy has the best work hardening properties as sheet metal. However, by tensile testing, a much more pronounced decrease in the work hardening for the 5050A compared to 3005 was measured after the strong predeformation (first draw). Flange cracking may also be a problem with rectangular cans. The defect is avoided by using a material with not a too highly developed deformation texture. Round cans produced from Al- Mg- alloys may develop ears parallel to the rolling direction. By adding Mn, the Al- Mg alloys may change to low 45[[ring]] earing materials. The rivets of easy open ends are produced by biaxial stretchforming, and alloys from the 3000 series exhibit superior properties compared to 5000 series alloys.
9:00 am
COMPUTER ASSISTED METALLURGY FOR PACKAGING ALLOYS: C. Sigli, H. Vichery, Pechiney CRV, BP 27,38340 Voreppe, France
A software has been developed in order to predict the yield strength of 3000 and 5000 alloys as a function of the process parameters. The main subroutines perform the calculation of:
* microstructure in the as- cast, homogenized and hot rolled conditions,
* yield strength as a function of microstructure and cold rolling reduction,
* yield strength as a function of the baking treatment.
A graphic module enables to readily visualize the stress- strain curve and recovery kinetics of a given alloy. An inverse modeling module (simplex method) has also been implemented in order to perform backward calculation, i.e. to optimize alloy composition and rolling parameters as a function of the required properties. Several examples of application will be demonstrated.
9:20 am
NUCLEATION AND GROWTH OF RECRYSTALLIZATION IN AN Al- 1Mn ALLOY DURING THERMOMECHANICAL PROCESSING: P.L. Orsetti Rossi, C.V.G. Industria Venezolana de Aluminio, C.A., Zona Industrial Matanzas, PO BOX 302, Puerto Ordaz, Venezuela; C.M. Sellars, The University of Sheffield, Department of Engineering Materials, Mappin Street, Sheffield S1 3JD, UK
A procedure based on quantitative optical microscopy has been used to investigate nucleation and growth of recrystallization in hot rolled and annealed Al- 1Mn (AA3003) as a function of strain (0.4- 0.71) and temperature (420[[ring]] C and 460[[ring]] C) at a constant mean strain rate of about 5 s- l. Despite the experimental scatter, site saturation seems to be a reasonable approximation for modelling purposes. During recrystallisation, the average growth rate decreases continuously probably due to concurrent recovery in the unrecrystallised fraction although the magnitude of the reduction suggests that a non uniform distribution in stored energy and concurrent precipitation must also play an important role.
9:40 am
SINGLE STEP PREHEATING OF AA3104 CAN BODY STOCK INGOTS: Scott L. Palmer, Ravenswood Aluminum Corporation, P.O. Box 98, Ravenswood, WV 26164; Zhong Li, Light Metals Research Labs., Dept. of Chemical and Materials Engineering, University of Kentucky, 177 Anderson Hall, Lexington, KY 40506
Comparison of a single- step versus two- step (controlled cooling) preheating practice has been investigated for AA3104 can stock ingots. Earing and tensile tests performed on final gauge H19 sheet revealed that earing tendencies were very similar for both processes, while tensile properties were slightly lower for the single- step practice. The difference in tensile properties was correlated to a difference in Mn supersaturation. Manganese precipitated in the form of a fine (<1 um) second phase dispersion was found to be a more effective hardener than if it was retained in solid solution. Texture development in the single step preheated material followed a different path than the two step process, but with the same final earing result in the H19 sheet. Manganese dissolution curves were developed for a variety of thermal histories based on resistivity measurements.
10:00 am BREAK
10:20 am
A TECHNIQUE TO MEASURE INTERMETALLIC SIZE DISTRIBUTION IN ALUMINUM CAN BODY STOCK: X. Wang, Corporate R&D, Reynolds Metal Co., Muscle Shoals, AL 35661; R. G. Kamat, Corporate R&D, Reynolds Metals Co., Richmond, VA 23261
Quantification of the intermetallic constituents in aluminum alloys is important in evaluating the metal performance during fabrication of products. For example, in aluminum D&I can body alloys the intermetallics play an important role in cleaning aluminum build- up on the ironing dies during the can- making process. On the other hand, beyond a certain size these constituents could potentially contribute to the tool wear and/or tear- offs. Hence, optimizing the size distribution of the constituents is very important. Differentiating the intermetallics by conventional etching and metallographic techniques has drawbacks. This technique is time consuming and the results can be subjective due to poor etching response for color differentiation of particles. In this study, a technique for quantifying the intermetallics using a scanning electron microscope coupled with an energy dispersive X- ray spectrometer integrated with an image analyzer is described. The intermetallic phase distribution in aluminum can body alloys is measured in an efficient manner. Particularly, the [[alpha]]-Al12(Fe,Mn)3Si phase fractions and size distributions were determined. The technique has been successfully used for evaluation of industrial homogenization practices and for intermetallic particle distribution in can body sheets from various producers.
10:40 am
BUCKLE STRENGTH LOSS IN 202 DIAMETER BEVERAGE CAN ENDS: M. S. Nagorka, T. C. Sun, Kaiser Aluminum and Chemical Corp., Center for Technology, 6177 Sunol Blvd., Pleasanton, CA 94566
202 diameter beverage can ends show a significant time- dependent drop in buckle strength. This drop, which can be over 83 kPa (12 psi) after 30 days at 38[[ring]]C (100[[ring]]F), is of concern to beverage packagers. This presentation will examine the temperature dependence of the strength loss phenomenon and how different alloys affect the magnitude of the strength loss. The process appears to be thermally activated- - activation energies calculated from strength loss data obtained at different temperatures will be compared with those of mechanisms that might be responsible for the strength loss.
11:00 am
PERFORMANCE EVALUATION OF CANSTOCK ALLOYS USING THE DRAW BEAD SIMULATOR: Jean V. Reid, Rajeev G. Kamat, Corporate Research and development, Reynolds Metals Company, P. O. Box 27003, Richmond, VA 23261
The DBS test has been found useful to evaluate lubrication conditions in the
drawbead during sheet metal forming operations. A study was undertaken to
evaluate the usefulness of this test in differentiating metallurgical, surface
texture, and lubrication conditions for canstock. The test allows the
determination of a friction coefficient under plastic deformation conditions.
In addition, the frictional force can be separated from the deformation force.
In this study, performance in the test is based on friction coefficient and
forces generated during the test as well as an evaluation of drawbead and
sample galling. The performance data is correlated with canstock mechanical
properties, metallurgical structure, surface texture characterization and
lubrication mode.
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