Byproducts/wastes of iron-and steelmaking processes and steel scrap are the main sources of iron units recycled in the steel plants. Direct recycling of the iron oxide wastes (dusts and sludge) in the blast furnace (BF) is however hampered by its chemistry (.0 . 1%Zn in the charge). Vaporisation, condensation, oxidation and circulation of zinc may collectively lead to the accumulation in the furnace. Very fine particles are deposited on other particles that have high surface areas which diminish BF refractory life and impair the quality of high quality pig iron produced. For effective continuous recycling of iron units, it is necessary to identify their sources, determine their composition and evolve device and appropriate technology for the treatment of zinc bearing units. The present paper analyses the process of zinc accumulation in the BF and derives an algebraic model to determine the extent of the accumulation. On the basis of analysis of zinc base formation, its recirculation in the furnace and other related productive units, a homograph (alignment chart) of zinc accumulation is designed. The paper also outlines the feasible processes of zinc removal from the close-looped system (sinter plant-BF-sinter plant).

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Studies on the effect of steel dust (EAF dust) addition on the mechanical properties of 6063 Aluminium alloy have been carried out. The cast composite samples contain steel dust from 2–20 wt% produced in sand mould. These cast samples were homogenized, cold rolled, and solution-treated. The solution treated samples were normalized in still air, some quenched in water while some were tempered after quenching. Tensile and hardness responses were determined in all these processed samples. The results obtained reveal that 10 wt% steel dust in aluminium 6063 improved the ultimate tensile strength to 111.09 MPa and a corresponding hardness of 51.2 HV. Microstructural analysis shows iron containing intermetallics which are well distributed in the matrix with its morphology depending on the heat treatment and deformation imposed on them. Tensile strength and hardness of the composites was also found to depend on the volume fraction of intermetallics in the matrix.

This paper presents the effect of deformation on the tensile strength, toughness, hardness and electrical resistance of aluminum 6063 alloy. Cast samples were cold rolled in the range of 0-24 percent thickness reduction and subjected to mechanical (static, dynamic) and electrical resistance tests. Results show significant improvement in hardness and electrical resistance properties of the alloy. The nature, amount and distribution of the secondary phase, Mg 2 Si, particles precipitated within the matrix which was influenced by the extent of cold-work, are responsible for the observed behaviour. The resistance of the alloy also depends on the degree of cold work carried out prior to use.

In the black world cup-shaped utensils cast or deep drawn are usually used for cooking purpose. The utensils are made from deep drawn aluminum alloy of the 1xxx series and for cast 6xxx series. The cylindrical shape utensil is subjected to domestic heating cycles and after a while, tiny hole-like features termed pits will appear. This development will eventually shorten the service life of aluminum cooking utensils. This article examines the chemical response of deep drawn and cast utensils made from 1017 and 6063 aluminum alloys, respectively, in solution of Lycopersicum esculentum at a temperature other than ambient temperature. The results show that cast cylindrical utensils pit much more readily than deep drawn utensils. This occurrence is traceable to the presence of microcracks as a result of hydrogen embrittlement phase, precipitation of brittle second phase particles and the fine texture in cast utensils. The aluminum alloy can fail by cracking along grain boundaries when exposed to specific environments.

Carbide precipitates in Thin Wall Ductile Iron (TWDI) used for automotive applications needs to be eliminated or reduced for improved strength, ductility, crack propagation resistance and good machinability. Ductile iron thin section profiles (≤3 mm) present danger of massive carbide precipitations in the as-cast sample. Precipitated carbide phase is brittle and negatively affects the mechanical properties of the iron matrix. The suppression of carbide formation is associated with the nucleating properties of the nodularizer and innoculant alloys. This treatment is vital in ensuring that carbide precipitation, flake graphite structure and non-nodular graphite phases are reduced or completely eliminated in the TWDI castings. Therefore, the temperature and technique of treatment would influence the yield of the process, and ultimately the mechanical properties. In this study, the effect of nodularization and inoculation treatment temperature on the microstructure and mechanical properties of TWDI castings is examined. The results indicate that good nodularity and nodule count with better percent elongations are achieved using low treatment temperatures in descending order of 1490˚C, 1470˚C and 1450˚C, but have negative effect at lower treatment temperature of 1430˚C. However, TWDI castings have superior properties in terms of nodule counts and nodularity at 1450˚C. Treatment temperature does not produce significant influence on ultimate tensile strength (UTS) and hardness of TWDI castings. TWDI castings show poor nodularity, nodule count and ductility at higher inoculation treatment temperatures of 1550˚C, 1530˚C and 1510˚C.

The production of quality high-yield reinforcing steel bars continues to receive attention from researchers across the globe due to its importance and contribution to a country GDP. In most of the developing countries, particularly Nigeria, empirical studies have shown that bars produced through conventional rolling requires appropriate modification of its chemical composition in order to obtain the desired mechanical properties such as strength. However, the high cost factor involved in composition adjustment makes such approach unattractive. Rather, the application of the combination of systems of controlled rolling and controlled cooling proves to be the best option. This system however, requires some variations in processing parameters to suit individual plant production peculiarities. In this paper attempt is made to study the production challenges and opportunities the steel millers are facing in Nigeria. Previous works in this area are also reviewed with a view to charting the way forward. Experimental studies and process monitoring were carried out at some designated rolling mills in Nigeria.