Métallurgie

Nombre total de résultats : 186
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Simulation and Modeling of Uncertainties in the Calibration of a Fluorescence Chemical Spectrometer (FRX)

S. Djemili, A. HAMOUDA, D. BERDJANE, B. Maalem (2018)
Article de conférence

Sensitivity analysis and uncertainty estimation are of major importance for the declaration of conformity of finished products. Models must be sought to analyze the test data. The main objective of this work is to establish reliable models to analyze our experimental data and validate them. So we have studied and used the Monte Carlo and Bootstrap simulation methods, we have been able to realize programs that calculate the uncertainty according to the ISO 8466 standard on X-ray fluorescence spectrometer samples from the URASM CRTI chemical analysis laboratory. Programs and interfaces are made with Matlab (GUI).Voir les détails

Mots clés : Simulation; uncertainties; Monte carlo; Bootstrap; calibration

Microstructural Analysis of the deformed 316Ti and 904L StainlessSteel

L. Rabahi, N. KHERROUBA, I. Hadji, B. Mehdi, R. Badji (2018)
Article de conférence

ch are used in the petroleum industry. The two steels have been cold rolled with two widthreductions of 50 and 95%. Results of the microhardness measurements performed on the twosteels indicated that the 316L stainless steel is harder than the 904L stainless steel. In addition,the higher the deformation amount the higher the microhardness values for the two steels. X-raydiffraction analysis based on the Rietveld refinement method has been conducted and revealed adecrease of the size of the coherent domain of diffraction as a function of the deformation. Thisdecrease is accompanied by an increase of the dislocation density. A correlation withmicrohardness and a comparative discussion between the two steels is presented in this sudy.Voir les détails

Mots clés : Cold rolling, 316Ti, 904L, Micro-hardness, Dislocation density.

Contribution to the improvement of the quality of continuous casting steels at Sider El-Hadjar-Annaba

K.HAMLAOUI, H.Bendjama, H.TAYOUB, KH.SLIMANI (2018)
Article de conférence

Continuous casting is the process between steel making and rolling. It consists of turning liquid steel into slabs, blooms, or billets. The molten steel comes into contact with the mold, it will solidify and the first phases of the steel will form. This study confirms the need to check the steel quality and the continuous casting parameters such as; casting speed, extraction rate, oscillation of the mold and lubrication during primary cooling. The main objective is to build a thermal model that is an important task for predicting temperature profiles on different sides and edges of the product, in order to optimize the crust of steel.Voir les détails

Mots clés : continuous casting - steel - mold - primary cooling – slab.

Contribution to the improvement of the quality of continuous casting steel at Sider El-Hadjar-Annaba

HAMLAOUI Katib, BENDJAMA Hocine, TAYOUB Hadjira, SLIMANI Khair-Eddine (2018)
Article de conférence

Continuous casting is the process between steel making and rolling. It consists of turning liquid steel into slabs, blooms, or billets. The molten steel comes into contact with the mold, it will solidify and the first phases of the steel will form. This study confirms the need to check the steel quality and the continuous casting parameters such as; casting speed, extraction rate, oscillation of the mold and lubrication during primary cooling. The main objective is to build a thermal model that is an important task for predicting temperature profiles on different sides and edges of the product, in order to optimize the crust of steel.Voir les détails

Mots clés : continuous casting - steel - mold - primary cooling – slab

Effect of root pass filler metal on microstructure and mechanicalproperties in the multi-pass welding of duplex stainless steels

Ahmed KELLAI, Azzedine Lounis, Sami KAHLA, Brahim IDIR (2018)
Article de journal

This paper is focused on the estimation of the effect of root pass chemical composition, in multi-pass GTA Weldments, onmicrostructure and mechanical properties of duplex stainless steel welds.We used two different fillermetals, the super duplex ER2594 and duplex ER 2209. Microstructures of different passes of welded joints are investigated using optical microscope andscanning electron microscope. The relationship between mechanical properties, corrosion resistance, and microstructure ofwelded joints is evaluated. It is found that the tensile and toughness properties of the first weldment, employing the combinationof ER 2594 in the root pass and ER 2209 in the remaining, are better than that of the second weldment employing ER 2209 allpasses, due to the root pass grains refinement and its alloy elements content as chromium Cr and nitrogen N. The microstructureindicates the presence of austenite in different forms on the weld zone of ER 2209, same in the case of ER 2594, but with highercontent and finer grains size, in particularWidmanstätten austeniteWA. Potentiodynamic polarization tests of the first weld metalevaluated in 3.5% NaCl solution at room temperature have been demonstrated a corrosion resistance higher than that of thesecond weld metal. This work addressed the improvement of the corrosion resistance using appropriate filler metal withoutgetting any structural heterogeneity and detrimental changes in the mechanical properties.Voir les détails

Mots clés : Gas tungsten arc welding (GTAW), duplex stainless steel, Root pass, Filler metal, Microstructure and mechanical properties

BEHAVIOURS OF DEFORMATION AND RECRYSTALLIZATION OF 3% SILICON STEEL USING WEDGE-SHAPE SPECIMEN

R. Benchouieb, S. Achouri, W. Ghelloudj, S. TLILI (2018)
Article de conférence

Hot deformation and static recrystallization behaviours of a low carbon 3% Silicon steel, which is ferritic structure at high temperatures, has been investigated using wedge-shape specimen with a single-pass hot rolling experiments. The hot-rolling tests were carried out at temperature of 900?C to 9mm thickness followed by holding at the same temperature (900oC). The volume fraction recrystallized increased with the increase in rolling reduction and holding time after rolling, although a plateau was observed in the relationship between the volume fraction recrystallized and the effective strain. The preferential area for the recrystallization was the previous grain boundaries, particularly triple points of boundaries where the strain was concentrated. An inhomogeneity of recrystallization in the transverse sections through the thickness of the deformed wedges was observed. It was concluded that in this fine grain size material of 3% Silicon steel, the knowledge of deformation and recrystallization behaviors needs better control of strain and temperature under wedge-shape material.Voir les détails

Mots clés : 3% Silicon steel, wedge-shape specimen, hot rolling, deformation variables, dynamic recovery, static recovery, static recrystallization.

Application of the Algerian diatomite in adsorption of diclofenac

Ouafia Ghabeche1, 2, Skander Boukhezar1, Mohamed Boulkra1, Hazem Meradi1, Sihem Benayeche1, Hinda Gueroui1, Naima Touati1, Kotbia Labiod1, Fayçal Aouadja1, Ouafia Ghabeche, Skander Boukhezer, Mohamed BOULKRA, Hazem MERADI, Sihem BENAYACHE, Hinda Gueroui, Naima Touati, kotbia LABIOD (2018)
Article de conférence

Mesoporous amorphous silica of non-toxic nature has interesting properties, in particular, its relatively large surface area, pores with adjustable diameter and abundant Si-OH bonds. The functionalization of this silica transforms it into an ideal candidate for biological applications such as cell marking, gene transfection or as contrast agents in MRI and especially in drug delivery systems. In this study, we try to use a natural amorphous silica: Algerian diatomite, for encapsulation and carrier of Diclofenac (DS), in this order, diatomite must be purified; the choice of purification mode plays an important role in the organization and volume pore of the final product. We use hydrochloric acid HCl (1%, 10%, 20%) for oxide removal, and then we test the treated diatomite in the absorption of the DS.Voir les détails

Mots clés : diatomite, mesoporous, absorption, diclofenac sodic, drug carrier, encapsulation

CONTRIBUTION TO CHARACTERIZATION OF NATURAL DIATOMITE

H. MERADI, L. ATOUI, K. LABIOD (2018)
Article de conférence

With the complex examination of raw material from a Sig deposit in Algeria in the region of Mascara area, physical, chemical and mineralogical properties of diatomite have been defined. It has been found that it is a dominantly amorphous material, sedimentary rock of the type silica-diatomite. The raw material consists of approximately 60% SiO2. Of the physical properties, more significant is porosity, which is higher than 60%. The raw material has a wide spectrum of possibilities for practical application: intensive absorbent for several types of liquids and chemical properties of the soil, natural insecticide, and filter water etc. For determination of the chemical contents, properties and origin of the raw material the following methods have been used, such as, chemical analysis, XRD analysis, optical microscopy and thermal analysis.Voir les détails

Mots clés : diatomite, X-ray, XRD, Sig.

Risk of Contamination of the Littoral lands by the mill scale in Annaba City-Algeria

B. Maalem, A. BALASKA, D. BERDJANE, L. Tairi, S. Djemili (2018)
Article de conférence

A significant amount of scale is produced during casting of ingots and processing of hot-rolled products. In the El Hadjar steel complex, during the various rolling operations, the amount of scale produced is approximately 0.1% of the annual production of the rolling mills. The quality of the thin sheet during rolling is affected by the behavior of the iron oxide layers formed on their surfaces. For this reason, acids and oils are used for the descaling of slabs and billets by means of pressurized water. The calamine, contaminated by these various acids and used oils, is rejected and stored involuntarily on important areas and pollutes soil and groundwater. Micrographic observations as well as x-ray diffraction analysis have shown that calamine consists mainly of iron oxides. Hematite and magnetite become the main components for oxidation times greater than 1 hour. Characterization tests have shown that calamine is dense (ρ = 4.8 g/cm3), its particle size is variable depending on the degree of oxidation (from 0.5 to 10 mm). Simultaneous thermal analysis showed that an increase in mass of the calamine sample with a release of heat. Studies are underway for the physico-chemical characterization of the soils of the storage areas.Voir les détails

Mots clés : Scale, Risks, soil, thermal analysis, granulometry, X-ray diffraction

Contribution à la détection des défauts dans les aciers au cours de leur solidification

TAYOUB Hadjira, BENDJAMA Hocine, HAMLAOUI Katib (2018)
Article de conférence

Le procédé de coulée continue occupe aujourd’hui une place importante dans l’industrie sidérurgique. Ce procédé se situe entre l’élaboration de l’acier et le laminage. Il est responsable principalement de la production de l’acier. Partant d’un acier liquide contenu dans une poche qui est coulé ensuite dans une lingotière sans fond, on obtient en sortie de machine de l’acier solide sous le format de brames, blooms ou billettes. Sous la lingotière sont disposés des rouleaux extracteurs qui font avancer le produit dans la machine. Entre ces rouleaux, un système de refroidissement est constitué de jets d’eau (refroidissement secondaire), pendant que la coulée progresse, l’épaisseur de la couche solidifiée augmente pour obtenir un produit complètement solidifié et qui admet des défauts (criques, ségrégations,...). Donc la qualité du produit obtenu est fortement dépendante du réglage du refroidissement secondaire. Pour cette raison, le présent travail consiste à étudier la présence des défauts dans les produits coulés lors de son passage en refroidissement secondaire.Voir les détails

Mots clés : acier, Coulé continue, refroidissement secondaire, défauts, solidification