International Journal of Iron & Steel Society of Iran
Year:2023 | Volume:20 | Issue:1|Papers Count:10

Ferroalloys are compounds of iron with other elements that have many applications in various industries. The production of ferroalloys is usually done in electric arc furnaces and by the carbothermic process. In this method, metal oxides are reduced by different carbon materials, and the type of carbon material used can affect the way the process is carried out and the quality of the product. Metallurgical coke is the most common reducing agent in the production of ferroalloys, but due to its increasing shortage, high price, and relatively high content of harmful impurities, manufacturers are looking for other options. Charcoal has less ash than other carbon materials, but due to environmental problems, its use is not common. Coal with the highest reactivity is not considered among the main options due to its high sulfur content and low compressive strength. Recently, semi-coke, which is prepared at a lower temperature than coke, has gained attention in the ferroalloys industry due to its unique characteristics (high fixed carbon, high specific resistance, high chemical activity, low ash, and low sulfur). Semi-coke improves the quality of ferroalloy and reduces energy consumption and production costs. So far, semi-coke has been used in the process of iron and ferroalloy production in a limited way, and their results show the advantages of the presence of semi-coke. Therefore, in this research, the carbon materials used in the production of ferroalloys, the advantages of semi-coke, and the production method of semi-coke are discussed.

Selective laser melting (SLM) is a manufacturing technique that can be used to create products with complex geometries and materials. This study investigated the microstructure and electrochemical behavior of SLM-processed 316L stainless steel (SLM-fabricated 316L SS) and a commercially wrought counterpart in a concrete pore solution. The results showed that SLMed 316L SS had a finer microstructure with ultrafine cellular/columnar grains than the wrought counterpart. This was due to the high cooling rate of the SLM process. The SLM sample also had a higher charge transfer resistance and lower corrosion current densities than the wrought counterpart, indicating better corrosion performance in alkaline media. This could be attributed to the fabrication method of the SLM- fabricated sample, which prevents the formation of harmful phases and defects. These properties indicate an improved corrosion performance of the SLM sample over the wrought counterpart. As a result, SLM can be a promising fabrication method for producing corrosion-resistant materials.

Double girder cranes are mostlyture or some specific parts of this crane go under Double girder cranes are mostly used for heavy loads. The steel structure or some specific parts of this crane go under extra load during the crane operation. The crane condition depends on many variables that change over time randomly. The current standards of Europe have not solved the effects of the forces on the fatigue damage. In this paper, reasons for the skewing of the crane from the main path, and wear of the wheels and rails of it, and the effect of the lateral and thermal forces on the double girder crane are presented. Experimental measurements and computer simulations are used for the analysis. The existence of symmetry in the crane design and operation period is very important. The carriage location influences the amount of force. The results show that for preventing movement difficulties in the rail and crane, it is recommended to cover the structure with the heat shield and insulation materials, especially those parts in exposure to the hot billet. Creating the expansion gap in rails of the crane needs to be obeyed according to the standards. Also, using the rail guide is very good to reduce the skewing of the crane. Furthermore, heat treatment and hardening of the  used for heavy loads. The steel strucwheels must be completely obeyed.

Considering the various pollutions caused by human activity, especially in the industry, which has led to the destruction of the environment and the reduction of the quality of human life, it has prompted human societies and governments to consider the issue of the environment as a concern and The important challenge in today's post-industrial age should be given more attention. Manufacturing companies and industries such as steel should also design and implement their production approach based on environmental standards to reduce this concern. One of the environmental factors in the steel industry is the choice of a green supplier, the present study is carried out using fuzzy Vicor multi-criteria decision-making processes in order to evaluate the environmental performance of suppliers. A supplier with the highest score is ranked number one. This means that the supplier has the highest environmental performance. Vicor technique selects and ranks the best supplier from among the options available in the supply chain. The total size of the statistical population is 30 people from the West Asia Steel Company, all of whom were given their opinion by completing the questionnaire. are According to the findings of the research, the ranking Finally, according to the collected data, the ranking of suppliers based on the fuzzy score is S3>S2>S1.

Steel Supply Chain (SSC) is a interpretative segment in Steel's value-creation process for ensuring on-time delivery of the right quality of raw materials, Work In Process (WIP), other goods and services to manufacturing sites, and finished products to the ultimate consumers. Graph theory provides a real-time, end-to-end view of the Steel supply chain, from suppliers to customers. By representing the supply chain as a network of interconnected nodes, graph theory provides a visual representation of the relationships between nodes including: suppliers, manufacturers, distributors, and customers. The main purpose of this study is to focus on Iran’s Steel Supply Chain (ISSC) based on complex adaptive network analysis and graph theory. Data collection performed by steel industry monitoring reports produced by relevant organizations. By mapping the Iranian SSC to the network in the Gephi environment (0.9.2), the graph theory applied to analyze node-level and network-level indices. This hypothesis tested that the corresponding network of the target SSC contained a Complex Adaptive System (CAS) which is an inception to combining social science insights to develop systems-level models and insights that allow for phase transitions and emergent behavior.

This study investigated the effects of varying laser power on the microstructure and tensile properties of DP590 steel joints. Three joints were prepared using three different laser power levels (400W, 450W, and 500W), while keeping all other factors constant. The results indicated that laser welding resulted in the formation of martensite in the fusion zone, leading to a notable increase in hardness. However, with increasing the laser power, the hardness increment decreased due to the presence of acicular ferrite and Widmanstatten ferrite alongside martensite. The heat-affected zone (HAZ) of all welds exhibited a region where hardness dropped below that of the base metal (BM) due to partial tempering of martensite. This softening effect intensified with higher laser power. The sample welded with a laser power of 400W failed early in the tensile test due to lack of penetration. Conversely, the other two samples failed within the softened zone, showing yield strength values similar to the BM and high joint efficiency values (92.5% for 450W and 89.5% for 500W) but with a noticeable reduction in elongation. Both DP590 steel and welded joints exhibited a two-stage work hardening behavior consisting of a transient stage followed by a stage III hardening.

In this study, effect of laser power on the microstructure and tensile properties of dissimilar joints between DP590 steel and AISI 1012 steel were investigated. For this propose, three joints were prepared by laser welding using the laser powers of 400, 450 and 500 W. Results showed the formation of a mixture of Widmanstätten ferrite (WF), polygonal ferrite and ferrite-carbide aggregate in the fusion zone (FZ). Although no trace of martensite phase was detected in the FZ and heat affected zone (HAZ) of the AISI 1012 steel side, but Formation of martensite in the HAZ of the DP590 steel side resulted in the local hardening, while tempering of the pre-existing martensite in the subcritical HAZ of the DP590 steel side led to the formation of a softened zone. Furthermore, the hardness gradually increased from the AISI 1012 steel base metal (BM) to the FZ due to grain refinement and formation of WF. The sample welded with a laser power of 400 W failed from the FZ at early stages of tensile testing due to a lack of penetration defect, while the samples welded with laser powers of 450 and 500 W exhibited ultimate tensile strength values slightly above that of the AISI 1012 steel, and a significantly reduced total elongation value compared to both BMs.

TiO2 nanoparticle coatings have beneficial antifungal and anti-bacterial properties, which make them a reliable alternatives to resist against the occurrence and growth of viral, bacterial, parasitic or fungal infections. In this article, we have successfully produced a unique TiO2 coating on mild steel substrate by using sol-gel deposition technique to improve its corrosion resistance and anti-fungal properties. The coating was deposited on a mild steel substrate by a dip coating technique followed by three different type of cooling rates: 1, 3 and 6 ˚C/min. The phase morphology, micro-structure and composition of the coatings were studied by X-ray diffraction and field emission scanning electron microscopy characterization techniques. Bio-corrosion behaviour was evaluated by conducting electrochemical impedance spectroscopy and potentiodynamic polarization tests in 0.9 wt % NaCl solution at 37 ˚C to simulate aggressive environment. The antifungal performances of the coating have been studied on Aspergillus nigger and Aspergillus flavus. The specimens Reduction of corrosion current intensity for coated specimens varies from 15.8 to 0.8 µA/〖cm〗^2and shifting open circuit potential (Eocp) from -1550 mV to -391 mV, for heating and cooling rate 6 and 1 ˚C/min, respectively. Shifting Eocp towards more positive values by decreasing heating and cooling rate of heat treatment, enhanced corrosion resistance by reducing porosities and cracks in the coating. It is worthy to note that the antifungal properties TiO2 nanostructured coating on Aspergillus nigger and Aspergillus flavus are 50 and 30 % after 2 months, respectively.

One of the most crucial factors influencing the strength and quality of steels is the presence of non-metallic inclusions. Studies demonstrated that non-metallic inclusions in industrial parts diminish their fatigue strength. On the other hand, their hardness is another influential parameter affecting the fatigue strength of steels. Therefore, this research investigated the impact of non-metallic inclusions on the fatigue strength of AISI 304 steel with three hardness of 170, 250, and 330 Vickers. This research revealed that as the hardness decreases, the fatigue strength of the part also decreases. Additionally, an examination of the failure surfaces of the parts using scanning electron microscopy (SEM) indicates that non-metallic inclusions are the root cause of fatigue failure in the samples. Finally, employing Murakami relations, parameters such as stress intensity factor and critical inclusion size were determined for steel with hardness levels of 170, 250, and 330 Vickers. The critical inclusion size for steel with hardness levels of 170, 250, and 330 Vickers was calculated as 32.7, 24.8, and 15 micrometers, respectively.

In recent years, attempts have been made to put aside the hard chromium coating due to environmental damage to its plating baths. Due to their low toxicity, the Cr, Ni-Cr, and Cr-Ni coatings produced in the baths containing Cr 3+ ions are perfect substitutes for the hard chromium coatings. In this study, Ni-Cr coatings were created using electroplating, and the effect of formic acid concentration as complexing agents was investigated. Cyclic voltammetry tests studied the electrodeposition mechanism of coatings. The SEM and XRD methods were used to investigate the coatings' microstructure. The pinch-on-disk and potentiodynamic polarization tests were used to study coatings' wear and corrosion behavior. The results of the cyclic voltammetry test showed that increasing the concentration of formic acid resulted in increasing deposition of chromium ions during electrodeposition. Increasing the formic acid concentration in the bath to 30 g/L increased the micro-hardness of coatings to values similar to that obtained for the conventional hard chromium coating. It was due to the formation of chromium carbides during the electrodeposition process, as revealed in XRD patterns of coatings. In this case, the chromium content of the coating increases to 86 weight percent, and the grain size of the coatings is reduced to 40 nm. The coatings' best corrosion and wear resistance was obtained at 30 g/L formic acid in the bath due to the coatings' high hardness and crack-free microstructure.