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10Journal of Siberian Federal University. Engineering & Technologies 2 (2015 8) 176-179
УДК 621.777
Adaptation of Method Combined Rolling-Extruding for Production of Semi-Finished Products from Graded Waste Chip of Aluminum Alloys
Nikolai N. Zagirov*, Sergey B. Sidelnikov, Vadim M. Bespalov and Konstantin V. Burmistrov
Siberian Federal University 79 Svobodny, Krasnoyarsk, 660041, Russia
Received 24.12.2014, received in revised form 16.02.2015, accepted 04.03.2015
Was proposed a device for obtaining deformed semi-finished products from chip of aluminum alloys with use combined methods of treatment. Carried experiments to obtain rods and receipted data about their mechanical properties.
Keywords: chip, aluminum alloys, combined rolling-extruding, mechanical properties, rods, density.
Адаптация способа совмещенной прокатки-прессования для изготовления полуфабрикатов и изделий из сортной сыпучей стружки алюминиевых сплавов
Н.Н. Загиров, С.Б. Сидельников, В.М. Беспалов, К.В. Бурмистров
Сибирский федеральный университет Россия, 660041, Красноярск, пр. Свободный, 79
Предложено устройство для деформированных полуфабрикатов из стружки алюминиевых сплавов с применением методов совмещенной обработки. Проведены эксперименты по получению прутков и получены данные об их механических свойствах.
Ключевые слова: стружка, алюминиевые сплавы, совмещенная прокатка-прессование, механические свойства, прутки, плотность.
One of promising area of development continuous extruding technology based on installations of combined rolling-extruding is the use them for obtaining rods and wire from non-compact metallic materials of which occupies a special place graded granular chips of
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* Corresponding author E-mail address: [email protected]
non-ferrous metals and alloys. The above approach is aimed for solution a number of practical problems, the most significant of which can be consider the use of more rational, compared to the traditional melting redistribution, ways to involving to the production circulation generated in one form or another in particular production different types of waste chips. The effectiveness of the implementation of this method of processing waste chips provided a clear organization of work on their collection and storage, caused by a decline of deadweight losses of metal, lower cost of electricity for the metal production, and also the environmental conditions of production. In addition for maximum performance of processing waste chips important to create conditions of uninterrupted operation used for this purpose aggregates for a sufficiently long period of time.
Known a device for force feeding of non-compact material (powder) into the rolls of rolling mill and rolling it in horizontal direction as a metal strip [1], consisting of a bunker a container and auger with a drive and setpoint block. Due to the pressure generated by auger in the container, the device sequentially seals, and moves metal material and through setpoint block send it to the rolls located in a horizontal plane. However, this device allows obtaining only rolled sheet in the form of tapes, which significantly limits the range of products.
Partial solution to this problem other version of the device [2] used specifically to obtain the wire and profiles. The device includes two rolls one of which is made with a creek, the other - with a ledge, which together covered caliber at the output of which is set matrix with the ability to clamp it to the rolls, and roll to capture the non-compact material and its supply to the caliber. This device allows realizing process of combined rolling-extruding and obtaining press-articles of various forms from non-compact metallic materials (powders, chip, granules, etc.). However, the degree of compaction, which is created with an additional roll not always sufficient to obtain a relatively compact billet. In this regard it is difficult in consequence to capture and compress metal by rolls, which significantly affects the quality of study material and the formation of the required press-articles structure. Therefore, there is no way to get the wire and profiles of the non-compact materials with controlled structure and improved mechanical properties.
Improve efficient of the process obtaining wire and profiles from non-compact materials allows the design of the device, protected by a patent for an invention [3]. Device circuit is shown in Figure 1, includes a heated container 1, prechamber 2, drive auger 3 placed in a container 1, roll with a creek 4 and roll with a ledge 5 forming a closed box pass 6 at the output of which is set matrix 7 with hydraulic clamp 8. The matrix is equipped with heaters 9.
Non-compact metallic material (chip) continuously supplied to the container 1 and using rotating auger 3 moves to the tapered portion of prechamber 2. In process of creation the necessary pressure using rotating auger 3 material is compacted and the formation of a more or less compact billet in a rectangular plot of prechamber 2. And shape of the inner cavity and dimensions of prechamber 2 chosen so that compaction of billet takes place gradually with the transition from round section diameter D to rectangular with maximum dimensions hmax x b.
Next driven to rotate rolls 4, 5 and billet enters in formed by these rolls closed caliber 6, filling it, crimped by rolls, moving to a matrix 7 pursed to the rolls by hydro clamp 8, extruded and pressed in the form of press-articles with given shape, for example, profiles circular section diameter dn through the matrix 7.
The presence of an intermediate prechamber allows before rolling stage make preliminary briquetting rf non-cnsnpacf matesial and fofm in the prncaambef rectafgulan billet with alie; necessary degsee of compaction suffioient for subsequent dsformatkm by extruding metal by rolls through the holo of maerix. In this case, to rrduce rssittnnee iq deformadion of the matesial and dherefore efforts eatrucion prechambed onn br equippef waft additional heaters provide a stable tempeeature conditions in the deformation rentea
For sueSalnable process of compaction in the prechamber necessaey thrf coefficient of material compaction g ranges between 3 to 5 [l]t thfi^t is the ratio of the cross secfkinal area Fi w(irlsCng cavity of pcechnmber dlhmetes D by logging i3 to (he granulaq maferiU and crats sectional area F0 compacted rectangular billet output from it equal
F = k2 =l...t, (1)
2 n°
D2
where F-i = ; n°= b- h°.
Having expressed thue value F0 through the lie;ight of calib er in the smallest section hmm which implements the maximum compression e during rolling, get
Fo = b ■ hmm---. (2)
1 - u
Substituting formula (2) into equality ( 1) and taking into account that to ensure relizability of process combined rolling-extruding [4] compressio n in rolling should be at least 50 % (e = 0,5), obtain as a result that diameter of the prechamber on rhe border of the container, where beginr forming billet, must be chosen from the ratio
where b - width of closed caliber; hmin - height of closed caliber at the lowest section.
Checking of the proposed design of the device was carried out in laboratory conditions of department of metal forming Siberian federal univeesity. Given the deduced formula were designed and manufactured rolls with diameter 200 mm, that after mounting them on one cage rolling mill DUO used fo produce rods diameter of 7 and 9 mm. Caliber size in the smallest cross section was hmin x b = 7 x 15 mm, and the size of compacted billet output from prechamber were 14 x 14,5 mm. As the test material used granular chips of aluminum alloy АД31. When the diameter ot prechamber on the botder with the container D = 30 mm compaction of material at rhe outlet of the prechamber was about 50-60 %. Compression in a closed cavity tetween rolls on the stage of lolling provided further compaction to a relative deasity of 85-90 %% and a subsequent extrusion therugh the matrix rod density reac lied values 97-99 %>.
To estimate the lever of mechanical properties obtained press-articles from each of the rods were taken a few fragments from which were grind out the samples with a standard aspect ratio for tensile testing. Tests themselves were carried out on a universal testing machine LFM400 with fixation of the entire course of the deformation in a separate protocol. Processing of received data which was carried out for five samples for each size with the use of well-known formulas showed that: range of values the ultimate tensile strength сВ for rod 0 7 mm ranges from 190 to 200 MPa, for rod 0 9 mm - from 175 to 185 MPa; range of values relative elongation 5 for rod 0 7 mm is from 14 to 18 %, and for rod 0 9 mm - 16-20 %.
Set out the specific application area og rods and obtained from them by drawing wire from chips alloy АДЗ 1 quite difficuft. However, it can be assumed that, because of the relatively low cost of production and taking into account achieved mechanical properties they can be usedc tor example, consumer goods products, in particular, the strapping wire irtesponsible use. Fow fhese products me chanical properties are not sffictly regulated, but it is believed that in the solid (unannealed) state tensile strength tor rhem to be at least S40-160 MPa, and elongttion - ar least 5-10 %.
[1] Vinogradov G.A., Katashinsky V.P. Theory of sheet rolling metal powders and granules. M.: Metallurgy, 1979.
[2] Sidelnikov S.B., Kornilov V.N., Dovzhenko N.N. and others. Patent 1692739 RF. Device to get the wire and profiles / IPC B 22 F 3/18, B21B 1/10. Publ. 23.11.91. Bul. № 43.
[3] Sidelnikov S.B., Zagirov N.N., Ivanov E.V., Bespalov V.M. Patent 2429943 RF. Device to get the wire and profiles from non-compact materials / IPC B 22 F 3/18, B 21 B 1/10. Publ. 27.09.2011. Bul. № 27.
[4] Sidelnikov S.B., Dovzhenko N.N., Zagirov N.N.. Combined methods of treatments of non-ferrous metals and alloys: a monograph. M.: MAKS Press, 2005.
(3)
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