New Four-Die Forging Devices (FDFD) Design Solutions and Open-Die Forging Technologies
Viktor Lazorkin,
Dmitriy Lazorkin,
Sergey Kuralekh
Issue:
Volume 7, Issue 1, March 2018
Pages:
1-8
Received:
18 August 2017
Accepted:
6 February 2018
Published:
6 February 2018
Abstract: Employment of four-die forging devices (FDFD) under various industrial environment on a variety of hydraulic presses differing in terms of design features and automation degree proved that in every particular case and with a view to particular production needs an individual approach is required to select both the proper FDFD design and the proper forging technology. Presented in this paper are various design solutions of FDFDs and various forging technologies based on employment of these specialized devices. The main selection criteria for proper device design and forging technology are: high production output, which should be significantly higher as compared to existing production technology output; improved metal quality and quality of products (in terms of dimensional accuracy and surface quality); cutback of the whole production cycle extent due to reduction of forging cycle, heating period and auxiliary operations duration, and higher good metal yield. The paper illustrates new FDFD design solutions and new technologies which meet these criteria for solving various technological tasks, and it also shows what changes to technological process can be eventually required to gain the maximum benefit from using the FDFD.
Abstract: Employment of four-die forging devices (FDFD) under various industrial environment on a variety of hydraulic presses differing in terms of design features and automation degree proved that in every particular case and with a view to particular production needs an individual approach is required to select both the proper FDFD design and the proper f...
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Reactivity of Glass Powder in Aqueous Medium
Monique Tohoué Tognonvi,
Léon Koffi Konan,
Séka Simplice Kouassi,
Hervé Bi Irié Gouré Doubi,
Ablam Zidol,
David Harbec,
Arezki Tagnit-Hamou
Issue:
Volume 7, Issue 1, March 2018
Pages:
9-14
Received:
12 February 2018
Accepted:
6 March 2018
Published:
27 March 2018
Abstract: Recycled glass powder (GP) has recently been widely used as a complementary cementitious material to replace a part of the Portland cement in concrete. However, unlike the chemistry of the Portland cement hydration, more studied and mastered, the mechanism of GP reaction that occurs in-situ during the mixture hydration, is less studied. To overcome this, a first study was focused on the reactivity of the anhydrous glass powder surface over time and its effect on physico-chemical and mechanical properties of concrete. The results showed a very good stability of GP surface. Actually, Portland cement mortars incorporating 20% GP at different ages exhibited the same required properties. The second step, which is the subject of this paper, consists of studying the behavior of GP alone in water and identifying species likely to involve in the hydration reaction in presence of the cement. pH of suspensions and chemical composition of leachates were monitored respectively by pH-meter and inductively coupled plasma mass spectrometry (ICP-MS) as a function of contact time, water-to-solid mass ratio (W/S) and GP particle size. Results reveal an instantaneous increase of pH after mixing GP with water resulting in the passage of surface alkali ions in the solution. Moreover, an enhancement of silicon content in solution is observed suggesting a partial dissolution of the glass network. The dissolution rate increases with increasing W/S ratio and decreasing particle size. Thus, dissolved silica species would react with portlandite from cement hydration explaining good mechanical properties generally observed in concrete containing GP at long term. Accordingly, due to its high amorphous silica content, GP could be an excellent alternative for conventional supplementary cementitious materials such as fly ashes which are not locally available.
Abstract: Recycled glass powder (GP) has recently been widely used as a complementary cementitious material to replace a part of the Portland cement in concrete. However, unlike the chemistry of the Portland cement hydration, more studied and mastered, the mechanism of GP reaction that occurs in-situ during the mixture hydration, is less studied. To overcome...
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