Steel Raw Materials Research Articles

Steel grades classification and heating defects detection of bearing steel bars via pulse eddy current testing

Nondestructive examination of bearing steel raw material is a crucial step in ensuring the production of bearing rings. Traditional nondestructive examination methods struggle with real-time sorting, leading to potential production risks. This study proposes a pulse eddy current testing (PECT) approach combined multidimensional features and classification algorithm, to realize the recognition of steel grades and heating defects of bearing steel bars. Firstly, the two-probes differential PECT system was established. Subsequently, pulse signals were collected, and 27 features in the time domain, and frequency domain were extracted and analyzed. Finally, two classification algorithms, BP neural networking and Rindom Forest, are used to classify bearing steel. Experimental results demonstrate the approach proposed can sort bearing steel, die steel, and high-speed steel bars. Furthermore, it is capable of distinguishing between various types (brand, heat number) of bearing steel bars and identifying their overheated or burnt conditions.

Green supply chain for steel raw materials under price and demand uncertainty

The scientific formulation of procurement and inventory plans is an important topic in the steel industry, when considering both economic and environmental impacts in an uncertain market environment. Robust optimization methods offer an effective solution to this problem. This study has investigated a multi-echelon and multi-period front-end supply chain centered on a steel enterprise under uncertain purchase prices and demand. The goal is to minimize the costs associated with mining, processing, transportation, procurement, and inventory along with the corresponding carbon emission costs. To address this issue, we present a robust rolling horizon model (RRHM) that considers the inventory capacity constraints of steel enterprise and incorporates ore grade requirements. Subsequently, the RRHM was reformulated into a solvable mixed-integer linear programming model, and the relationship between the robust model and a specific deterministic model was established. Finally, the model was validated by generating instances based on real scenarios. The results demonstrate that the robust rolling horizon model proposed in this paper outperforms both the Sample Average Approximation (SAA) strategy and the (s, S) strategy in terms of cost and robustness. In addition, a sensitivity analysis of the key parameters was conducted. The findings reveal that the unit inventory, mining, and carbon emission costs have a limited impact on the total cost, highlighting the robustness of the model. These findings provide valuable insights into the green and sustainable development of the steel industry, enabling the formulation of effective strategies to mitigate the impacts of uncertainties.

Supplier Selection Modeling and Analysis in the Metal Casting Industry Using Analytical Hierarchy Process

This study presents a supplier selection problem of a raw material using an analytical hierarchy process. In the existing process, the delivery of raw materials experienced delays and impacted the production process. Therefore, this paper aims to determine the criteria for supplier selection and provide recommendations for the best vendor to be selected from the last request for quotation document. Analytical Hierarchy Process (AHP), as a multi-criteria approach, was utilized in this research, starting from determining criteria, the weight of criteria, and the final score for each supplier. Through discussions with the company’s expert, procurement department, and users, as well as a review of the previous studies, this research defined three criteria, each consisting of three sub-criteria. The AHP approach was utilized to evaluate and determine the weights for the three criteria, yielding the following results: quality (62%), price (28%), and delivery (10%). The identified criteria, sub-criteria, and respective weights are subsequently utilized in a supplier selection scenario. Three suppliers of mild steel raw materials were evaluated using the weights of the criteria and sub-criteria obtained. Supplier 1 was selected because of having the higher alternative value of 0.602. The use of AHP in supplier selection is often impractical and contains subjectivity. Therefore, further research can be performed by integrating AHP with other methods, such as weighted scoring, to facilitate further the vendor selection process and integration with other methods, such as fuzzy logic, to reduce subjectivity.

Reduction of natrojarosite and laterite nickel ore leaching residue composite using palm kernel shell reducing agents at temperatures of 1300-1450℃

Lateritic nickel ore processing through hydrometallurgical route generates a significant amount of residue from the leaching stage. Two examples of hydrometallurgical process residues, namely natrojarosite and leaching residue can potentially be used as secondary raw materials for the iron and steel industry. A relatively high sulfur content of up to 12% is a severe issue because the sulfur threshold value for steel raw materials is 1%. Therefore, it is necessary to reduce the sulfur content in natrojarosite and leaching residue to meet the standards as a secondary raw material for the iron and steel industry. In this research, reduction of natrojarosite, laterite nickel ore leaching residue, and palm kernel shell reducing agents composite was conducted in varying amounts of palm kernel shell reductant of 25-100% using a non-isothermal method at an initial temperature of 1000°C with a final temperature of 1300-1450°C and an isothermal method of 1000°C, 1300°C, and 1450°C for 2 hours. The results showed that an excessive amount of reductant (≥25%) would inhibit the formation of iron metal at macrosize (above 0.35 mm). Reduction, both by non-isothermal and isothermal methods, results in decreasing sulfur content in the metal phase as the reduction temperature increases, but a sulfur-rich matte phase is still observed in all experimental conditions. The proportion of the metal phase produced is getting higher and more separated from the slag phase as the temperature increases. The optimum condition was obtained at a non-isothermal reduction of 1450°C using a 25% reducing agent which resulted in iron and sulfur content in the metal phase of 88.53% and 0.49%, respectively, with a metal-matte phase proportion of 65.56%. In this case, slag was dominated by liquid phase with a FeO content of 7.64% and a viscosity of 7.313 PaS.

Perbandingan Pengadaan Persediaan Bahan Baku Dengan Menggunakan Metode EOQ dan Min Max pada PT XYZ

PT XYZ is an industrial company that produces vehicle spare parts. So far, raw material inventory planning has been carried out based on estimates of past needs, methods like this will result in uncertainty raw material needs which will cause total inventory costs to increase, stockouts, and overstocks. This research aims to evaluate the company's raw material inventory procurement, to obtain optimal raw material inventory procurement. The research methods used are normality tests, forecasting, and comparison of the EOQ & Min method where the best method is proposed to be applied in the company. The data collection techniques used were observation, interviews, and documentation. The research results show that companies should use the EOQ method for steel raw materials and Min Max for copper raw materials, which will save inventory costs by 25.16% or IDR 9,340,698. Apart from that, the safety stock value, maximum inventory, and reorder point are also known to avoid stockouts and overstocks. By implementing inventory procurement methods, companies can find out the maximum inventory that should be in the warehouse, expedite production operational activities, and save space usage which of course benefits the company.

Investigating the surface roughness of 3D printed metal parts in case of thin 20 µm build layer thickness

In the case of the laser powder bed fusion technology of metals, the surface quality often does not meet the requirements for use. In addition, the surface can be characterized by different values on different surfaces of the part, depending on the preparation of the workpiece and the technology. The parameters affecting the surface roughness and their effect are also explored in the case of different raw materials and technological settings. In this research, the knowledge was expanded in the case of one of the thinnest layer thicknesses under various conditions. The effect of the angle of orientation during the preparation for the upskin and downskin surfaces of the component, in different directions on the surface of the components were determined in the case of titanium and stainless steel raw materials. In addition, the roughness-reducing effect of the shot peening process was also investigated.Graphical abstract

CIRCULARITY IN THE STEEL PACKAGING SECTOR: AN ANALYSIS OF THE MAIN BARRIERS AND OPPORTUNITIES

AbstractPaper aims: Map the life cycle of metal packaging, investigate the barriers and enablers to the adoption of circular practices in the steel packaging sector in Brazil.subject of study: Consist of adoption of a circular model of production and consumption, in which post-consumer raw materials are reintegrated into their respective value chains.Research method: A literature review is combined with qualitative research involving key sector experts to examine how the Brazilian steel packaging sector can transition to a more circular value chain.Main findings: This research indicate that steel packaging has the potential to join a group of products with closed-loop production cycles and that steel can be recycled indefinitely without losing the original properties. Implications for theory and practice: If endless recycling of steel raw materials, there will be no need to mine new ore for new steel packaging.

Pengaruh Variasi Holding Time pada Proses Pack Carburizing dengan Arang Tempurung Kelapa Barium Carbonat Terhadap Sifat Fisik dan Mekanik Baja ST 42

Iron-based production machine components are chosen to support productivity. Steel is a metal material that is easily found on the market, but it has not fulfilled the desires of consumers in the market. This steel can be hardened by heat treatment (heat treatment). The surface treatment process is carried out to obtain the desired hardness, this can be done by increasing the carbon (C) element in the steel material, the carbon content in the standard steel structure is 0.3% - 0.59% the carbon content will have an effect. on hardness, one way to increase the element carbon (C) in steel and increase the hardness on its surface is by carburizing. This research will examine the hardness level of low carbon steel by using a pack carburizing process with different times of 2; 2.5 and 3 hours and the quenching process with pure water media.. The purpose of this study was to determine the effect of holding time on the pack carburizing process with coconut shell charcoal - barium carbonat on the hardness value of ST 42 steel. Besides that for effect of holding time on the pack carburizing process with coconut shell charcoal on the microstructure. There are differences in the surface hardness and microstructure values ​​ before and after the carburizing process. Where the highest hardness value occurs at a holding time of 3 hours with a hardness value of 872.9 HVN or an increase of 382% of the raw material and is supported by the dominance of the martensite phase which is more and more evenly distributed. Compared to the ST 42 steel raw material before the pack carburizing process was carried out, the hardness value was 174.8 HVN. A dominant microstructure consisting of a ferrite phase and a little bit of pearlite dominance.

COMPARISON OF EFFECTIVENESS INVENTORY CONTROL OF EOQ METHOD WITH COMPANY METHOD IN STEEL MATERIAL FABRICATION KRAKATAU POSCO

PT. Krakatau Posco, is the largest steel manufacturing company in Southeast Asia that produces slabs and plates. This study aims to compare the effectiveness of controlling inventory of steel material fabrication workshop with the EOQ method and compared with the current method of the company in an effort to prevent the unavailability of such steel material fabrication. Inventory control using the EOQ method is expected to provide solutions for inventory control, and optimal ordering in order to obtain savings for inventory costs (Total Inventory Cost) at PT. Krakatau Posco. The method used is an interview and take the necessary data, then conduct an initial analysis using the ABC method to clarify the data that has been carried out at PT. Krakatau Posco, controls inventory using EOQ, determines safety stock, ROP and maximum inventory. By controlling the ordering and inventory also expected to provide significant savings for the company, by reducing inventory costs (Total Inventory Cost). The conclusion of this research is the EOQ method is the right method for controlling steel raw material fabrication to meet the production and repair processes at PT. Krakatau Posco and with this method the results of total inventory costs are also more efficient.

A Novel Named Entity Recognition Scheme for Steel E-Commerce Platforms Using a Lite BERT

In the era of big data, E-commerce plays an increasingly important role, and steel E-commerce certainly occupies a positive position. However, it is very difficult to choose satisfactory steel raw materials from diverse steel commodities online on steel E-commerce platforms in the purchase of staffs. In order to improve the efficiency of purchasers searching for commodities on the steel E-commerce platforms, we propose a novel deep learning-based loss function for named entity recognition (NER). Considering the impacts of small sample and imbalanced data, in our NER scheme, the focal loss, the label smoothing, and the cross entropy are incorporated into a lite bidirectional encoder representations from transformers (BERT) model to avoid the over-fitting. Moreover, through the analysis of different classic annotation techniques used to tag data, an ideal one is chosen for the training model in our proposed scheme. Experiments are conducted on Chinese steel E-commerce datasets. The experimental results show that the training time of a lite BERT (ALBERT)-based method is much shorter than that of BERT-based models, while achieving the similar computational performance in terms of metrics precision, recall, and F1 with BERT-based models. Meanwhile, our proposed approach performs much better than that of combining Word2Vec, bidirectional long short-term memory (Bi-LSTM), and conditional random field (CRF) models, in consideration of training time and F1.

PENGARUH VARIASI ARUS PENGELASAN SMAW TERHADAP KEKERASAN LOGAM INDUK DAN LOGAM LAS

Construction of substantial components in a building, both static and dynamic, is the construction that is supported by connection elements. The connection element serves to connect one structure to another. Welding is a metal joining method that takes advantage of the penetration of heat or heat produced. The problem of selecting the type of current (Amper) also determines the amount of heat input required in metal melting. This study aims to present the trend of the hardness of the joints (weld metal and parent metal) to changes in current strength, which in this case is represented by the hardness factor caused by welding temperature. The method used is the experimental method, which is supported by the SMAW welding method and hardness testing on HAZ and weld metal using the Rockwell HRD-150 type hardness tester. The results showed that the average hardness value of ST 37 steel raw material obtained from the test results was 48.6 HRB. The hardness value of the weld metal for the welding process 70 Ampere, 90 Ampere, and 110 Ampere is lower than the hardness value of the raw material. Based on these conditions, there was an increase in the HAZ hardness value in all specimens for the 110 Ampere welding process with a hardness value of 50.2 HRB or 1.9% compared to the raw material hardness value.

Effect of gas pressure on conduit plasma atomization for fabricating spherical stainless steel powder

In this study, spherical stainless steel powders are produced using the conduit plasma atomization. Parameters of the conduit plasma atomization process with gas variations of 1.5 bar pressure, 2 bar pressure, 2.5 bar pressure with 316L stainless steel raw material with a current of 25 Amperes, feed speed of 2 mm3/s. The results of stainless steel powders were observed using a digital microscope (Dino-Lite AM4115), scanning electron microscopy (SEM-FEI-Inspect F50), and energy dispersive spectroscopy (EDS). To ensure the purity of the resulting 316L stainless steel spherical powder, EDS was used for qualitative and quantitative elemental analysis. The results showed that the 316L stainless steel spherical powder particles varied in size from 35 µm to 140 µm, making them ideal for powders metallurgy application. The effect of gas pressure on the powder weight percentages for particle sizes 50 µm – 100 µm for 1.5 bar pressure, 2.0 bar pressure, and 2.5 bar pressure were 67.14%, 78.71%, and 81.73%, respectively. It is possible that this could happen because to break down molten metal into smaller size droplets, it is needed the kinetic energy of larger gas pressure. So that large gas pressure can produce more small particle size compared to small gas pressure.

COMPARISON OF EFFECTIVENESS INVENTORY CONTROL OF EOQ METHOD WITH COMPANY METHOD IN STEEL MATERIAL FABRICATION KRAKATAU POSCO

PT. Krakatau Posco, is the largest steel manufacturing company in Southeast Asia that produces slabs and plates. This study aims to compare the effectiveness of controlling inventory of steel material fabrication workshop with the EOQ method and compared with the current method of the company in an effort to prevent the unavailability of such steel material fabrication. Inventory control using the EOQ method is expected to provide solutions for inventory control, and optimal ordering in order to obtain savings for inventory costs (Total Inventory Cost) at PT. Krakatau Posco. The method used is an interview and take the necessary data, then conduct an initial analysis using the ABC method to clarify the data that has been carried out at PT. Krakatau Posco, controls inventory using EOQ, determines safety stock, ROP and maximum inventory. By controlling the ordering and inventory also expected to provide significant savings for the company, by reducing inventory costs (Total Inventory Cost). The conclusion of this research is the EOQ method is the right method for controlling steel raw material fabrication to meet the production and repair processes at PT. Krakatau Posco and with this method the results of total inventory costs are also more efficient.

Rancang Bangun Sistem Informasi Penjualan Bahan Baku Gypsum dan Baja Berbasis Web

Abstract - CV Gypsum Griya Indah is a market leader distributor company in the industry of gypsum and mild steel raw materials. The sales system at this company is still manually felt to be less effective in attracting customers. By implementing information systems at Griya Indah CV Gypsum which is engaged in sales and wants to expand its marketing area through an E-commerce website. Aside from being a means of promotion, E-commerce websites can simplify the process of ordering and purchasing goods. E-commerce websites do not only act as information media but can also expand sales areas to reach all of Indonesia and internationally. For consumers, websites simplify the process of purchasing goods needed. In this study the method used is the waterfall method which describes a systematic and sequential approach to software development, starting with the specification of user needs and then continuing through several stages as follows planning, modeling, construction, and the delivery of the system to customers / users, then end with complete software support generated. By using webset as a media. 
 Keywords: E-commerce Website, Gypsum Raw Material, Light Steel

ANALYSIS OF THE PROCESS OF IRON SAND PROCESSING INTO SPONGE IRON IN ORDER TO SUPPORT THE DEFENSE INDUSTRY OF STEEL RAW MATERIALS

<p>The number of iron sand reserves is mostly spread in the coastal waters of Indonesia, from the coast of Sumatra, the southern of Java to Bali, the beaches of Sulawesi, beaches in East Nusa Tenggara (NTT), and the northern coast of Papua. Total reserves for ore are 173,810,612 tons and metal as much as 25,412,652.62 tons. But its utilization was not optimal because PT. Krakatau Steel, and PT. Krakatau Posco has produced steel plates only 24,000 to 36,000 tons per year. While the need for steel plates for the shipping industry each year requires 900,000 tons per year. With the need for raw material for steel plates in the form of iron sponges with Fe ≥ 60%, PT. Krakatau Steel is still imported from abroad. The proof is PT. Krakatau Steel before and during the year 2000 still imported Iron Ore Pellets from the countries of Sweden, Chille and Brazil for 3,500,000 tons per year. This condition is the cause of the national steel industry unable to compete with the foreign steel industry because imported raw materials are subject to import duties. This is an opportunity to build a steel raw material company because all this time the steel raw material industry in Indonesia has only two companies. This condition encourages the manufacture of iron sponges, with the process of making iron sponges with technology adapted to installed production capacity. This study analysed the manufacture of iron sponges using Cipatujah iron sand, as raw material for the manufacture of iron sponges, with the results obtained in the form of iron sponges with the highest levels of Fe ≥60.44%. This can be used for the purposes of raw materials for steel making PT. Krakatau Steel (PT. KS), because so far PT. KS claims that Fe <60% local sponge iron products. This can encourage the independence of steel raw materials, which impacts on the independence of the defence industry. But the government must also protect and prioritize steel raw materials for national production for national steel production. With the national government steel industry, the consortium of vendors supplying raw material (iron sponge) to maintain the quality and supply of continuous sponge iron.</p><p><strong>Keywords</strong>: iron sand, iron pellet, iron sponge</p>

Platts introduces daily newsletter focused on steel raw materials markets

Platts introduces daily newsletter focused on steel raw materials markets

Study and Design of Chromium Ore Smelting Reduction Process for Producing Stainless Steel in a Converter

This paper describes the concept of the construction of steelmaking shop, which is carried out as part of a modernization plan aimed at creating a 21st century environmental-friendly iron and steel works, designs the smelting reduction process of producing stainless steel crude melts in a 150 t converter and presents an outline of the equipment specifications and the conditions of operation, according to the blowing conditions of 185 t smelting reduction converter of No.4 steelmaking shop in Chiba Works of JFE Steel. In the future, a rational production system will be constructed by flexible selection of raw materials in response to changing stainless steel raw material prices and further improvement in productivity and quality, making the maximum use of functions of the equipment.

The Effect of Texture on Friction of AlSl304 Stainless Steel

Polycrystalline materials develop texture as a result of various manufacturing processes. In this paper the effect of texture of material on wear resistance and friction coefficient of AISI304 stainless steel samples was studied. Three different types of surface textures were produced from the same stainless steel raw material. Texture measurements were performed to obtain information from the specimen surface. Friction tests were performed using a Micro Scratch tester with the capability of monitoring acoustic emission and frictional force during scratch tests.

Single Planetary Mill Rolling Method of High Grade High alloy Steels

It has been known that producing good quality hot strips with ductile micro structure of high grade high alloy steels having big single weight by hot rolling is very difficult.However on the base of the results obtained after a long years' study of hot rolling of high grade high alloy steels by single planetary mill, quite a few merits of the said mill can be effectively available in case of rolling various high alloy steels and also they, comparatively, can be rolled with ease.Even a high speed steel that can hardly be processed could also be hot rolled into an ductile hot strip by 400φ single planetary mill.In this case, the underwritten conditions are necessary:1. The workrolls are to be thick.2. To use an assembly of 8 piece planetary workroll.3. To hot roll a slab as thin as approx 70% of high carbon steel raw material into a strip.4. The ratio between “t” of plate thickness and “l'” of length of touching arc is to be more than 0.60Also a correct calculation method of “l'” is being introduced.