Application of Al-Ti-B Wire in the New High Strength Wear Resistant Piston Materials

The combination of the conventional forming processes rolling and extruding enables the continuous production of cross-sectional aluminum long products. Regarding power consumption and resulting material specifications, the combined process offers various advantages in comparison to its conventional alternatives [1, 2]. The combined rolling and extrusion process is in an early stage of maturity. The production of pure aluminum wire is state of the art. The material flow within the process can partially reproduced by the use of numerical simulations [3]. Some process specific characteristics need to be understood and controlled to obtain a better process design and to enable the future production of complex cross-sectional products. This paper describes the results of experimental and numerical investigations regarding the combined rolling and extrusion process. The test specimen of a visioplastic examination on an industrial scale plant [3] was examined by the use of metallography. Those results where compared to a numerical simulation of the industrial experiment. The comparison of these results where then linked to some specific characteristics of the process. The existence of a dead zone with a shape comparable to the conventional indirect extrusion process was proved. The deformation zone of the combined process was divided into four zones which can be differentiated in the experimental as well as the numerical results. General design rules were derived from this differentiation. These design rules were used to optimize the forming geometry of an industrial scale plant. Critical process forces where reduces and resulting scrap material was minimized.

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Characteristics of the Combined Rolling and Extrusion Process

The results of experimental studies on the development of a method for obtaining titanium-containing bar ligature, the study of its structure and modifying ability are presented. The distinctive features of the new technology are the use of titanium sponge and/or titanium shavings as titanium raw materials, the primary alloying of aluminum with titanium, and then boron, the introduction of titanium in two stages: initially, 2/3 of the titanium metal raw materials are dissolved in the aluminum melt, and the remaining amount is introduced after the reduction of potassium tetrafluoroborate. Pre-impregnation of the titanium sponge with halide-containing flux and the use of a briquetted mixture of KBF4 + Al-powder are also provided. The experimental technology for the preparation of the Al–Ti–B melt is described, the extraction of titanium and boron into the ligature is calculated, its microstructure is investigated, and the chemical and molecular compositions of the resulting slags are determined. Deformation treatment for the production of bar ligature was carried out by the method of direct extrolling which made it possible to level the defects of the cast structure. It is established that the use of high-speed crystallization-deformation in the implementation of the combined direct extrolling process makes it possible to obtain alloying bars of a given diameter at minimal energy consumption with the required complex of mechanical and operational properties. A quantitative assessment of the modifying ability of the experimental cast-iron ligature and the deformed cast-iron rod obtained by the direct extrolling method was carried out in comparison with the mass-produced cast-iron ligature produced by KBM Affilips (the Netherlands/Belgium). Based on theoretical and experimental studies, the composition and technology for producing Al–Ti–B modifying ligature using titanium sponge and/or shavings and potassium tetrafluoroborate with a content of 3.0 ± 0.3% titanium and 1.0 ± 0.2% boron as alloying additives have been developed, which meets the requirements for the composition of aluminum ligatures.

Development of Technology for Obtaining Titanium-Containing Bar Alloy for Modifying Aluminum Alloys

Based on the finite element analysis for the combined rolling-extrusion process, the stress-strain state, force on the tool, and the moments on the rolls are calculated as a function of the tool temperature and the rotational speed of the rolls. The calculations are performed for an Al – Ti – B system alloy containing 5% titanium and 1% boron, widely used in the industry for melt modification when casting ingots of aluminum alloys. The authors proposed ligature rods from this alloy to be produced by the method of combined rolling-extruding (CRE), which has significant advantages in comparison with the traditional technologies of continuous casting-rolling and discrete extruding. Therefore, for the design of technology and equipment for combined processing, it is necessary to have preliminary design data on the temperature-velocity conditions and energy-force parameters of the metal deformation process. For 3D modeling in a software package SolidWorks® the model of the combined rolling-extruding process was created, which was imported into the package DEFORMTM. The simulation process of producing a rod diameter of 9.5 mm by installing rolls with diameters of 462 mm and a protrusion stream 394 mm with rolling reduction of 50% drawing ratio during extruding 6.2 at the rotation speed of 9 rpm data obtained by the temperature distribution metal, strain rates, normal contact stresses on the tool and internal stresses in the metal. In addition, graphs of the change in the forces and moments of rolling acting on the rolls are plotted, depending on the rotational speed of the rolls and the required power of the drive motor is calculated. The obtained data were used in the design of new industrial equipment for combined rollingextruding of aluminum alloys and experimental studies, which confirmed the adequacy of the obtained modeling results.

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N. N. Dovzhenko

Papers

3D modeling of combined rolling-extrusion of alloying rods of Al – Ti – B