Sponsored by: SMD Titanium Committee, MDMD Shaping and Forming Committee
Program Organizers: Prof. Isaac Weiss, Prof. Raghavan Srinivasan, Mechanical and Materials Engineering Dept., Wright State University, Dayton, OH 45435; Dr. Paul Bania, Timet Corporation, Timet-Henderson Technical Laboratory, P.O. Box 2128, Henderson, NV 89009; Prof. Daniel Eylon, Graduate Materials Engineering, University of Dayton, Dayton, OH 45409
Tuesday, AM Room: B5-6
February 6, 1996 Location: Anaheim Convention Center
Session Chairpersons: P. Allen, Timet Corporation, Timet-Henderson Technical Laboratory, P.O. Box 2128, Henderson, NV 89009; D. Musi, NEFM International Inc. Monaca, PA 15601
8:30 am Invited
COLD FORMING OF BETA TITANIUM ROUNDS AND FLATS: Charles Pepka, Renton Coil Spring Co., 325 Burnett N., PO BOX 880, Renton WA 98057
The manufacture of springs and sheet metal components at Renton coil spring has changed throughout the years. The exotic materials of the late 70's is common place in today's manufacturing. Just in time production has brought additional demands requiring faster setup times and more accurate work to be done. Cold formability of titanium has allowed the material to become financially competitive to stainless and steel material. The considerations of weight and corrosion resistance have allowed titanium materials to dominate in many venues. The paper will cover forming of beta titanium rounds and flats in many sizes. Cold forming of spring wire and stamp and form parts from sheet materials will be discussed.
9:00 am
Ti-6Al-2Sn-4Zr-2Mo ALLOY FOILS COLD ROLLED FROM STRIP CAST BY THE PLASMA MELT OVERFLOW PROCESS: I. M. Sukonnik, Texas Instruments, MS 10-28, Attleboro, MA 02703; T. A. Gaspar, Ribbon Technology Corporation, P.O. Box 30758, Columbus, OH 43230; W. D. Brewer, R. K. Bird, NASA Langley Research Center, MS 188A, Hampton, VA 23665
The combination of direct strip casting and cold rolling to produce titanium alloy foils offers many economic and metallurgical advantages over conventional ingot metallurgy practices. A Ti-6Al-2Sn-4Zr-2Mo alloy strip, 0.5-mm-thick and 100-mm-wide, cast by the plasma melt overflow process was cold rolled to a 0.07-mm-thick, fully dense foil. The microstructure of the direct cast + cold rolled foil was more isotropic than ingot metallurgy foil. The chemical composition, gas content, microhardness and tensile properties of the direct cast + cold rolled foil was measured and found to meet or exceed MIL specifications.
9:20 am
THE RELATIONSHIP BETWEEN TEXTURE AND ANISOTROPY OF MECHANICAL PROPERTIES IN TITANIUM ALLOYS: Susan M. Kazanjian, Hinrich Hargarter and E. A. Starke, Jr., Department of Materials Science and Engineering, University of Virginia, Charlottesville, VA 22901
The texture of a material is the primary basis of its anisotropic behavior. Consequently, texture development during various processing steps is important in order to understand and optimize processing parameters to develop the desired isotropy of mechanical properties and to obtain an insight into the mechanisms associated with deformation and fracture. A well known example of the importance of texture is in deep drawing where a high r-value and low planar anisotropy is necessary to prevent tearing. During the past twenty years significant advances have been made in the characterization of textures in a very quantitative way by the introduction of the orientation distribution function (ODF) which can be calculated from several pole figures. This talk will describe texture measurements of two titanium alloys and the correlation of parameters determined from the ODF's with mechanical properties.
9:40 am
ADIABATIC SHEAR BANDS FORMED BY PUNCHING IN Ti-6Al-4V ALLOY: Y. Kosaka, J. Kosin, Oregon Metallurgical Corporation, 530 34th Ave., Albany OR 97321
It is generally understood that the formation of adiabatic shear bands (ASB) is closely correlated to shock or dynamic loading. In this study, the formation of ASB along fracture surface was investigated by punching test with moderate cross-head speeds in Ti-6Al-4V alloys. Microstructure and strength of specimens were changed by heat treatment which includes mill anneal, recrystallize anneal, beta anneal, and solution treatment and aging. ASB was observed along fracture surface in any specimens. The width of ASB was in a range of 10 to 20 micrometers. Shear strength of samples heat-treated at beta appeared to be lower than that of alpha/beta processed samples. These values will be discussed in conjunction with their microstructures and other metallurgical factors.
10:00 am
THE EFFECTS OF RESIDUAL WORK ON THE AGEING RESPONSE OF BETA ALLOYS: P. J. Bania, P. G. Allen, Timet Corporation, Timet-Henderson Technical Laboratory, P.O. Box 2128, Henderson, NV 89009
When metastable beta alloys undergo deformation processing, particularly at elevated temperatures, the stored residual work is usually utilized to drive subsequent recrystallization. However, due to other considerations such as, for example, grain size, the recrystallization process may not always be driven to near completion. Also, at times an intermediate step of subgrain formation or polygonization is developed. Whether it is simple incomplete recrystallization or sub-grain formation/polygonization, the lack of complete recrystallization leaves added driving force that can significantly influence the precipitation process during ageing. This paper will review some experiences with metastable beta alloys relating to the effects of incomplete recrystallization on ageing behavior.
10:20 am
COLD WORKING OF LCB TITANIUM ALLOY: I. Weiss, R. Srinivasan, M. Saqib, N. Stefansson, S. LeClair, Mechanical and Materials Engineering Dept. Wright State University, Dayton, OH 45435; A. Jackson, Manufacturing Technology Branch, Wright Laboratories/Materials Directorate, Wright Patterson AFB, OH 45433
A study was undertaken to evaluate the cold forming characteristics of the low cost beta titanium alloy (LCB-Titanium) containing iron and molybdenum. Room temperature compression tests were conducted at strain rates in the range of 0.01s-1 to 5s-1. The material work hardens at slow strain rates, while deformation heating and localization causes the material to flow soften at fast strain rates. The deformation behavior of the alloy will be discussed in terms of the microstructure of the alloy and changes in the mode of deformation observed by optical and transmission electron microscopy.
10:40 am BREAK
10:50 am
DEFORMATION BEHAVIOR OF BETA21S SHEET: J. Reshad, I. Weiss, Mechanical and Materials Engineering Dept., Wright State University, Dayton, OH 45435; T. F. Broderick, S.L.Semiatin, Processing Science Group, Wright Laboratory, Materials Directorate, Wright Patterson AFB, OH 45433
The general bending and stretching characteristics of .060" beta21S sheet will be presented. In particular, the sensitivity of the material to fail by localized necking will be discussed relative to strain hardening and rate sensitivity behavior. As the alloy is heat treatable, the influence of pre-conditioning heat treatments on deformation and failure will also be presented.
11:10 am
FLOWFORMING AND SPINNING OF TITANIUM AND ITS ALLOYS TO PRODUCE LOW COST INDUSTRIAL COMPONENTS: D.M. Zimmermann, Spin Forge International, El Segundo, CA 90245
The use of titanium and its alloys is usually justified for aerospace applications on the basis of using a cost premium to save weight compared to steel and other materials. Most industrial applications do not offer similar cost vs. weight trade off calculations in order to decide bill of materials. Flowforming and spinning technology has recently been applied to produce a number of parts in the industrial sector with reasonable success. The advantage of limited machine cycle (spinning) times, reduced scrap generation, and higher input to application yield weight has reduced costs to attractive levels. In some components, titanium can even be less expensive than steel. Several different applications are reviewed: temperature probe casing, micro-tunneling bands, small pressure tanks, and nuclear waste cannisters. Alloys reviewed include commercially pure titanium, beta titanium alloys, and Ti-6Al-4V.
11:30 am
HYDROGEN TECHNOLOGY OF SEMIPRODUCTS AND PRODUCTS PRODUCTION FROM HIGH STRENGTH TITANIUM ALLOYS: A.A. Ilyin, V.K. Nosov, A.M. Mamonov, V.N. Uvarov, A.V. Alexandrova, Moscow State University of Aviation Technology after K. Tsilkovsky, Metals Science Dep., Petrovka St. 27, K-31, Moscow, Russia, 103767
High strength titanium alloys such as Ti-10-2-3 and VT22 are processed by hot forging. New treatment technology of titanium alloys base on reversible hydrogen alloying give the possibility the use of deformation process at the room temperature (cold deformation). In the paper, the scientific basis and technological schemes for the production of sheets, foils and wire from Ti-10-23 and VT22I high strength titanium alloys by means of cold rolling are described. Products, such as, hemispheres and "cups" produced by cold sheet forming are presented in material. Alloying with hydrogen not only gives the opportunity to produce shapes and semiproducts at the room temperature, but also, allows the development of special texture, such as, {111} <110> and {111}<211>, in the ß phase titanium alloys. This type of texture is favorable for further cold deformation and for decreasing anisotropy in the mechanical properties of the deformed products. The application of hydrogen technology in this manner permits high strength to be developed in the products without quenching and ageing. Obtaining the high strength level of this alloys under vacuum annealing is important for sheet and foil products.
11:50 pm
MANUFACTURE OF TITANIUM ALLOY FASTENERS: Viacheslav A. Volodin, Igor A. Vorobiov, Normal Corporation, 74 Litvinova St., Nizhny Novgorod, 603600, Russia
Titanium and its alloys, which are very attractive for commerical
applications, are used in aerospace structural and engine components where
weight is important, and in chemical, oil and gas, nautical and medical
applications, where corrosion resistance is required. Titanium has also been
used in consumer products, such as sporting goods and jewelry. Russian industry
produces a wide range of titanium alloys for use as fasteners. This paper
discusses the application of cold headed fasteners in several applications
which meet DIN and ISO standards. One of the best Russian alloys is BT-16,
containing a small amount of Al and relatively large amounts of Mo and V, which
can be heat treated to strengths up to 1470 MPa. This alloy is compared with
Ti-6Al-4V for various applications. The application of titanium alloys for
fastening fragile composite and glass-fiber plastic materials will also be
discussed.
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