Physical Modeling of Semi-continuous Casting for Developing an Industrial Technology of Producing Ingots From New Deformable Aluminum Alloys

A physical model of a semi-continuous casting unit (SCCU) has been manufactured and tested, designed to develop a technology for casting flat and cylindrical ingots from experimental aluminum alloys for subsequent metal forming. The SCCU includes two induction melting furnaces with a tilting mechanism, a rotary mixer, a metal path system, a vertical casting machine, a jib crane, water supply, power supply, monitoring and control systems. SCCU testing was carried out on six heats of alloy 1580 of the Al-Mg system with the addition of scandium. In the first three ingots the scandium content was 0.05% (wt.). In the second series of three heats ingots with 0.075% (wt.) scandium were cast. The ingots had a high surface quality, did not have casting defects, and there were no inclusions of primary intermetallic compounds Al3(Sc, Zr) in the structure of the ingots. The bottom and runner parts of the ingots were cut off, all faces were milled and subjected to homogenization annealing in a two-stage mode: the first heating at 350 °C, 3 h, the second heating for 1 h to 425 °C, 4 h. Then the billets were hot rolled from 40 to 5 mm, annealed at 380 °C, 1 h, rolled at room temperature to a thickness of 1 mm and annealed at 350 °C, 3 h. After that, tensile mechanical properties were tested. The results of modeling ingot casting were tested in industrial conditions when casting a large ingot with a cross section of 2100×500 mm. A template was cut from the ingot with the dimensions of a billet for rolling, as that obtained from an experimental ingot cast at the SCCU. The billet was subjected to hot and cold rolling according to the conditions used for rolling the experimental ingot. At the same time the modes of heat treatment of sheet semi-finished products were also repeated. The mechanical properties of sheets of alloy 1580 rolled from experimental and industrial ingots practically did not differ. This proves the reliability of casting modes for ingots obtained at the SCCU and tested for casting industrial ingots.

Simulation of Process Rolling Plates from Alloy of Al-Mg System Economically Doped with Scandium

The modes of hot and cold rolling of plates from an alloy of the Al-Mg system alloy, doped with scandium in the range of 0.10-0.12%, are modeled. At the first stage of work, using the DEFORM-3D software package, we simulated the process of hot sheet rolling at the Quarto 2800 mill, in order to obtain a billet for further cold rolling. Analysis of the simulation data showed that with the adopted compression mode, the metal forming and temperature conditions of rolling make it possible to obtain plates up to 45 mm thick, without defects, with rational power loading of the equipment. Further modeling of the regime of cold rolling of plates with a thickness of up to 31.5 mm showed that cold rolling can be carried out in 4 passes, provided that the stress and rolling force do not exceed the permissible values. At the second stage of work, we conducted an experimental verification of the obtained simulation results both in industrial and in laboratory conditions. It was found that the value of the total compression leading to the destruction of the samples, depending on the rolling conditions, should not exceed 21-30%. At this degree of deformation, the rolled metal from the alloy under study has high strength and plastic properties. Subsequent industrial verification of the research results confirmed that this alloy is quite advanced technologically, while it has high deformability, both during hot and cold rolling, which allows us to recommend it for sheet deformed semi-finished products in the manufacture of structural products for various purposes.

PENGARUH REDUKSI CANAI TERHADAP SIFAT MEKANIS BAJA KARBON RENDAH DENGAN SAMBUNGAN FLASH BUTT WELDING

Steel plate making can be produced by hot and cold rolling method. To obtain the optimal results, the production on the cold rolling mill (CRM) must be carried out continuously. This CRM is equipped with a flash butt welding machine to connect between one plate and anothers. The purpose of this research is to determine the effect of thickness reduction on mechanical properties of steel JIS 3141. The method used in this study is experimental, namely mechanical properties testing at weld area, heat affected zone (HAZ) and base material. The thickness reductions used in this research are 0%, 69,78%, 71,56% and 73,33%. The material characteristics observed were hardness, tensile strength, yield strength, elaongation and corrosion rate. From this study it is known that the thickness reduction 73.33% resulted the best mechanical properties. The values ​​of hardness, tensile strength, yield strength and corrosion rate were 82.26 HRB, 644 N / mm2, 501 N / mm2 and 1.3844 mpy, respectively.

Microstructure Evolution during the Production of Dual Phase and Transformation Induced Plasticity Steels Using Modified Strip Casting Simulated in The Laboratory

Instead of conventional steel making and continuous casting followed by hot and cold rolling, strip casting technology modified with the addition of a continuous annealing stage (namely, modified strip casting) is a promising short-route for producing ferrite-martensite dual-phase (DP) and multi-phase transformation-induced plasticity (TRIP) steels. However, at present, the multi-phase steels are not manufactured by the modified strip casting, due to insufficient knowledge about phase transformations occurring during in-line heat treatment. This study analysed the phase transformations, particularly the formation of ferrite, bainite and martensite and the retention of austenite, in one 0.17C-1.52Si-1.61Mn-0.195Cr (wt. %) steel subjected to the modified strip casting simulated in the laboratory. Through the adjustment of temperature and holding time, the characteristic microstructures for DP and TRIP steels have been obtained. The DP steel showed comparable tensile properties with industrial DP 590 and the TRIP steel had a lower strength but a higher ductility than those industrially produced TRIP steels. The strength could be further enhanced by the application of deformation and/or the addition of alloying elements. This study indicates that the modified strip casting technology is a promising new route to produce steels with multi-phase microstructures in the future.

Study of strength properties of semi-finished products from economically alloyed high-strength aluminium-scandium alloys for application in automobile transport and shipbuilding

The results of a study on the strength of rolled products from aluminium alloys doped with scandium under various processing conditions of hot and cold rolling are presented. The regularities of metal flow and the level of strength of deformed semi-finished products from aluminum-scandium alloys are established, depending on the total degree of deformation and the various modes of single reduction during rolling. It is shown that when using one heating of a cast billet to obtain high-quality semi-finished products, the temperature during the rolling process should not be lower than 350-370°, and the total degree of deformation does not exceed 50-60%. It was found that the semi-finished products from alloys with a content of scandium in the range 0.11-0.12% in the deformed state had elevated values of ultimate tensile strength and yield strength of the metal, which allows them to be recommended for industrial production of sheet metal products.

Physical Modeling Technological Regimes of Production Deformed Semi-Finished Products from Experimental Aluminium Alloys Alloyed by Scandium

The combination of weldability, corrosion resistance and sufficient strength make it possible to use deformed semi-finished products from the Al-Mg system alloys for sheathing ships' hulls, in car, aircraft and rocket construction, as well as in other areas of industry. To increase the strength characteristics, it is promising to alloy them with small additives of metals such as titanium, zirconium, scandium, and others. In this paper, studies were carried out to obtain deformed semi-finished products (strips, rods and wires) from aluminum alloys in which the scandium content varied from 0.1 to 0.25%. For this purpose, various metal treatment conditions simulated in the laboratory of School of Non-Ferrous Metals and Material Science in Siberian federal university. For the preparation of sheet semi-finished products regimes of hot and cold rolling of a cast billet simulated from a thickness of 40 mm to a thickness of 3 mm. For the preparation of sheet semi-finished products, the modes of hot and cold rolling of the cast billet from a thickness of 40 mm to a thickness of 1-3 mm have been modeled. To produce a welding wire with a size of 2×2 mm, a combined casting and rolling-extruding (CCRE) process was simulated to produce a 9 mm billet and its further rolling in square gauges. Rods with a diameter of 9 mm were produced on a combined processing unit, and wire on a rolling mill with a roll diameter of 130 mm. In accordance with the research program, the mechanical properties of hot-deformed, cold-deformed and annealed sheet semi-finished products were measured. Then the semi-finished products were welded together with the obtained wire and the quality and properties of the welded joint and their corrosion resistance were evaluated. Research results are currently used to develop industrial technologies for the production of sheets and plates from experimental alloys of the Al-Mg system doped with scandium.