Transformation of austenite to duplex austenite-ferrite assembly in annealed stainless steel 316L consolidated by laser melting

This work aims at the development of carbon steel AISI 1536 through the microalloying addition of boron. Three grades of this steel with different content of boron up to 0.0055% were melted in 100 kg induction furnace. The pro- duced steels were hardened at 960°C for 30 min., followed by tempering at different temperatures and durations. All hardened steels have martensite phase as illustrated with microstructures and X-ray diffraction. Hardness of all tem- pered steel samples was measured to calculate the activation energies of carbon migration through martensite phase. The results indicated that the activation energies of carbon migration through martensite phase decreases with the in- crease of boron content due to its positive effect on the crystallinity of martensite phase. Also, the results showed that the addition of boron up to 0.0023% can improve the steel properties at the lowest temperature and tempered time.

https://file.scirp.org/pdf/JMMCE20121000020_42105587.pdf

Influence of Boron Additions on Mechanical Properties of Carbon Steel

Additive manufacturing is revolutionizing the way of production and use of materials. The clear tendency for shifting from mass production to individual production of net-shape components has encou ...

/pdf/stainless-steels-fabricated-by-laser-melting-scaled-down-266od197uj.pdf

Stainless steels fabricated by laser melting : Scaled-down structural hierarchies and microstructural heterogeneities

This paper covers the effect of heat treatment on the mechanical properties of medium carbon steel. The main objective of this project is to investigate the hardness and impact properties of medium carbon steel treated at different heat treatment processes. Three types of heat treatment were performed in this project which are annealing, quenching and tempering. During annealing process, the specimens were heated at 900°C and soaked for 1 hour in the furnace. The specimens were then quenched in a medium of water and open air, respectively. The treatment was followed by tempering processes which were done at 300°C, 450°C, and 600°C with a soaking time of 2 hours for each temperature. After the heat treatment process completed, Rockwell hardness test and Charpy impact test were performed. The results collected from the Rockwell hardness test and Charpy impact test on the samples after quenching and tempering were compared and analysed. The fractured surfaces of the samples were also been examined by using Scanning Electron Microscope. It was observed that different heat treatment processes gave different hardness value and impact property to the steel. The specimen with the highest hardness was found in samples quenched in water. Besides, the microstructure obtained after tempering provided a good combination of mechanical properties due to the process reduce brittleness by increasing ductility and toughness.

https://iopscience.iop.org/article/10.1088/1757-899X/114/1/012108/pdf

The effect of heat treatment on the hardness and impact properties of medium carbon steel

Hot-working die steel should possess good high temperature strength, tempering resistance, ductility and reasonable cost. Thus, H13 is widely used for forging, extrusion and die casting. Resistance to surface wear of hot working die steel plays an important role in imparting good finish to the products. The properties required of hot die steel for a given application can be obtained by controlling heat treatment parameters which produces major changes in microstructure. This paper intends to find the impact of austenitizing temperature, tempering temperature and tempering time on the wear behavior of H13 die steel. After heat treating samples at austenitizing temperature of 1020, 1040 and 1060
 $$^{\circ }$$
 C; tempering temperature 540, 560 and 580
 $$^{\circ }$$
 C; tempering time 1, 2 and 3 h, experimentation on pin-on-disc tribotester is done to measure the H13 die steel sliding wear and coefficient of friction. Using Box–Behnken design a response surface method model is developed to find the impact of above heat treatment parameters and the adequacy of model is verified through the analysis of variance (ANOVA) technique. The optimized heat treatment set predicted by desirability function approach is verified experimentally and the results are found close to the predicted results.

Interpreting H13 steel wear behavior for austenitizing temperature, tempering time and temperature

Engineering materials, mostly steel, are heat treated under controlled sequence of heating and cooling to alter their physical and mechanical properties to meet desired engineering applications. In this study, the effect of heat treatment (annealing, normalising, hardening, and tempering) on the microstructure and some selected mechanical properties of NST 37-2 steel were studied. Sample of steel was purchased from local market and the spectrometry analysis was carried out. The steel samples were heat treated in an electric furnace at different temperature levels and holding times; and then cooled in different media. The mechanical properties (tensile yield strength, ultimate tensile strength, Young’s modulus, percentage reduction, percentage elongation, toughness and hardness) of the treated and untreated samples were determined using standard methods and the microstructure of the samples was examined using metallographic microscope equipped with camera. Results showed that the mechanical properties of NST 37-2 steel can be changed and improved by various heat treatments for a particular application. It was also found that the annealed samples with mainly ferrite structure gave the lowest tensile strength and hardness value and highest ductility and toughness value while hardened sample which comprise martensite gave the highest tensile strength and hardness value and lowest ductility and toughness value.

/pdf/effect-of-heat-treatment-on-mechanical-properties-and-10idgo05sk.pdf

Effect of Heat Treatment on Mechanical Properties and Microstructure of NST 37-2 Steel

The main purpose of the research primarily focused on the development of sustainable social indicators and to test their usefulness and applicability in the Nigerian textile sector in terms of social performance. The integrated Fuzzy Best-Worst method (FBWM) and Fuzzy inference system (FIS) was presented to aid in the evaluation of these indicators. The outcomes demonstrate that employee rights received the highest score of 0.206 in the study. Employee rights are regarded as the most crucial and critical factor. Furthermore, among the indicators, fair salary has the highest global weight. The case company's sustainability performance index was 0.248, which was in the "poor" performance category. A case study was conducted in a Nigerian textile industry to demonstrate the effectiveness and efficiency of the proposed method. These findings will assist managers and policymakers in the textile manufacturing industry, particularly in emerging economies such as Nigeria, in developing strategies to lay the groundwork for social sustainability and transition to truly sustainable textile manufacturing industry.

https://www.ajol.info/index.php/njtd/article/download/240346/227222

Assessing Social Sustainability Performance in Textile Industry using Integrated Fuzzy Best-Worst Method and Fuzzy Inference System

Given the significant scale of the textile industry, there has been rising global concern over the sustainability of this sector. Consumers’ satisfaction with textile materials plays a pivotal role in sustainable textile products in competitive markets. There have been limited studies on understanding customers preferences and the selection criteria for sustainable textile products in developing countries, where the uncertainties of demand and supply abound. The sustainability impact of textile products in developing countries has not been thoroughly investigated in previous studies. This study aims to examine sustainability criteria to evaluate the selection of sustainable textile products. Thus, using a case study of the textile industry in Nigeria, this paper provides a fuzzy decision support system to analyze the selection of sustainable textile products in the country's textile industry. The study employed an integrated fuzzy best-worst method and fuzzy inference systems to evaluate textile products. The fuzzy best-worst method was used to calculate the weight of each criterion while a fuzzy inference system was employed to select the best product. The proposed method was utilized in a real-world case study, and some managerial implications were determined. Based on three distinctive evaluative assessments, the proposed method was shown to be valid and robust.

T. G. Fadara

Papers

Effect of Heat Treatment on Mechanical Properties and Microstructure of NST 37-2 Steel

Assessing Social Sustainability Performance in Textile Industry using Integrated Fuzzy Best-Worst Method and Fuzzy Inference System

A decision support system for sustainable textile product assessment