Topic Review
Innovative Application of Metallic PCMs in Metal Casting
Phase Change Materials (PCMs) are materials that release or absorb sufficient latent heat at a constant temperature or a relatively narrow temperature range during their solid/liquid transformation to be used for heating or cooling purposes. Although the use of PCMs has increased significantly in recent years, their major applications are limited to Latent Heat Storage (LHS) applications, especially in solar energy systems and buildings. Metallic PCMs appear to be the best alternative to salts and organic materials due to their high conductivity, high latent heat storage capacity and wide-ranging phase change temperature. Recent studies indicate that besides their conventional applications, metallic PCMs can be used in casting design to control the solidification microstructure as well as the feedability and defect formation in castings. Use of metallic PCM-fitted chillers is believed to open new horizons in smart control of the casting structure.
  • 147
  • 23 Jun 2022
Topic Review
Chloride-Induced Corrosion of Carbon Steel in Cracked Concrete
Corrosion is an electrochemical reaction consisting of anodic and cathodic half-cell reactions. Micro-cell corrosion refers to the situation where active dissolution and the corresponding cathodic half-cell reaction occur in adjacent parts of the same metal. For a steel reinforcing bar in concrete, the surface of the corroding steel can act as a mixed electrode containing both anode and cathode regions connected by the bar itself. Macro-cell corrosion can also form on a single bar exposed to different environments within the concrete or where part of the bar extends outside the concrete. In both cases, the concrete pore solution functions as an electrolyte.
  • 71
  • 16 Jun 2022
Topic Review
Basic Oxygen Furnace (BOF) steelmaking is, worldwide, the most frequently applied process. According to the world steel organization statistical report, 2021, it saw a total production share of 73.2%, or 1371.2 million tons per year of the world steel production in 2020. The rest is produced in Electric Arc Furnace (EAF)-based steel mills (26.3%), and only a very few open-hearth and induction furnace-based steel mills. The BOF technology remains the leading technology applied based on its undoubted advantages in productivity and liquid steel composition control. The BOF technology started as the LD process 70 years ago, with the first heat applied in November 1952 in a steel mill in Linz, Austria. The name LD was formed from the first letters of the two sites with the first industrial scale plants, Linz and Donawitz, both in Austria. The history and development of the process have been honored in multiple anniversary publications over the last few decades. Nevertheless, the focus of the steel industry worldwide is significantly changing following a social and political trend and the requirement for fossil-free energy generation and industrial production to be in accordance with the world climate targets committed to in relation to the decades leading up to 2050.
  • 305
  • 09 Jun 2022
Topic Review
Continuous Casting Practices for Steel
Continuous casting practices for steelmaking have been constantly evolving ever since the early 1930s, when Junghans was first researching ways to pour liquid steel into an open-bottomed, water-cooled mold, to withdraw the partially solidified steel out of it, continuously, in the form of a round or square billet or slab. He envisioned that once these continuously cast shapes had become fully frozen, their solidified ends could be cut off for further processing. In this way, they could be transformed into “rebar” to reinforce concrete, or into bars from which nails, bolts, tire cord wire, etc., could be fashioned, etc. However, long before that, Sir Henry Bessemer had proposed a far more elegant approach, involving two, contra-rotating rolls, into which liquid steel is poured, to produce a thin solidified sheet of steel directly, within a few milliseconds. This is referred to as a Near Net Shape Casting Process. After 150 years of trying, CASTRIP, a subsidiary of NUCOR, BHP, and IHI, made this process a commercial success, where many previous attempts had failed. However, there is an even better NNSC process, referred to as HSBC, or "Horizontal Single Belt Casting", that has also been commercially successful. The HSBC process is capable of casting many different grades of steel, unlike the Bessemer CASTRIP process, by casting ~10 - 15mm thick strips, that can then be rolled down to a final sheet ~1.5 - 0.5mm. thickness, in a one-step continuous process.  
  • 426
  • 06 Jun 2022
Topic Review
Material Extrusion Additive Manufacturing of Metal
Material extrusion additive manufacturing of metal (metal MEX), which is one of the 3D printing processes, has gained more interests because of its simplicity and economics. Metal MEX process is similar to the conventional metal injection moulding (MIM) process, consisting of feedstock preparation of metal powder and polymer binders, layer-by-layer 3D printing (metal MEX) or injection (MIM) to create green parts, debinding to remove the binders and sintering to create the consolidated metallic parts.
  • 726
  • 02 Jun 2022
Topic Review
Beneficiation of Rare Earth Elements
The rapid depletion of high-grade rare earth elements (REE) resources implies that future supplies may be augmented with low-grade ores, tailings, and other unconventional resources to meet cut-off grades and, subsequently, supply demands. There are distinct differences in the beneficiation response of REE and gangue minerals in the tailings. Gravity, wet magnetic, and froth flotation separation methods produced significantly varying REE recoveries and upgrades. Tabling presented a better potential for REE minerals upgrade compared to the Knelson Concentrator (KC). However, wet magnetic separation produced two REE “rich” preconcentrates. The two REE preconcentrates were subsequently upgraded via froth flotation. In terms of recovery, the best result was achieved during the multistage flotation process carried out on the tailings “feed” in the presence of hydroxamic acid and depressants. With high recoveries obtained using such readily available conventional separation methods, the tailings provide additional REE value to the primary commodities.
  • 136
  • 24 May 2022
Topic Review
Critical MIM + SH Processing Parameters
Metal injection molding (MIM) combined with the use of a space holder (SH) is a very attractive route for the fabrication of highly porous titanium and titanium alloy components for biomedical applications. This approach allows fine control of the morphology, architecture, and purity of very complex net-shaped components.
  • 146
  • 13 May 2022
Topic Review
Influencing Factors on Al Alloys Superplasticity
Aluminum alloys can be used in the fabrication of intricate geometry and curved parts for a wide range of uses in aerospace and automotive sectors, where high stiffness and low weight are necessitated.  Superplasticity is a process in which polycrystalline materials undergo several hundred to several thousand percent of tensile elongation at an appropriate temperature and strain rate. It is greatly effective in reducing the weight and production cost by minimizing the processing steps of machining and joining. 
  • 125
  • 10 May 2022
Topic Review
Trends and Challenges in the Indian Steel Industry
India is the 4th largest iron ore producer and the 3rd largest coal producer in the world. Coal is also identified as one of the major sectors of “Make in India”, which is an initiative by the Government of India launched by the prime minister. India is also the world’s largest producer of sponge iron: about 37 million tons per annum. 
  • 139
  • 22 Apr 2022
Topic Review
Possibilities and Opportunities in the Indian Steel Industry
Demand for iron ore has been increasing with the increased production of iron and steel in developing countries such as India and China. However, the quality of iron ore has deteriorated over the years globally due to long-term mining. The low-grade iron requires beneficiation before agglomerating for use in the iron-making process. The iron ore interlocked with silica and alumina has to be liberated for efficient beneficiation.
  • 202
  • 22 Apr 2022
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