PROPERTIES OF AUSTENITE STAINLESS STEEL MICROALLOYED WITH TELLURIUM AND ZIRCONIUM

Stainless steel X8CrNiS18-9 (standard EN 10088-3: 2005) is the most commonly used austenitic stainless steel due to its good machinability. This steel has high mechanical and working properties thanks to a complex alloying, primarily with the elements such as chromium and nickel. The content of sulphur present in the steel from 0.15 to 0.35% improves machinability. Microalloying with tellurium and zirconium (individually and in combination) in most cases leads to improved properties of this stainless steel, compared to melt without alloying additives, e.g. the melt microalloyed with tellurium and especially melt microalloyed with zirconium and tellurium has significantly better machinability compared to the melt without alloying elementsThe addition of sulphur, which is the cheapest available additive for free machining, will impair not only the transverse strength and toughness but also the corrosion resistance. However, while sulphur improves machinability at the same time decreases the mechanical properties particularly toughness. This work aims to test machinability, corrosion resistance, and mechanical properties of the mentioned steel, as well as the chemical composition of non-metallic inclusion

INFLUENCE OF BORON, ZIRCONIUM, AND TELLURIUM ON THE IMPACT TOUGHNESS OF X8CrNiS18-9 STEEL

Steel X8CrNiS18-9 (standard EN 10088-3: 2005) is the most commonly used from the group of austenitic stainless steel in terms of machinability. The content of sulphur present in the steel from 0,15 to 0,35% has the exclusive task to improve the machinability. However, while sulphur improves machinability it simultaneously reduces the resistance of steel to corrosion but also affects the decrease in mechanical properties particularly steel toughness. Due to its harmful effect on the steel, as well as the fact that the non-metallic inclusions are insufficiently tested for this type of high-alloy steel the aim of this study is to determine the appropriate microalloying possibility to modify the non-metallic inclusions. The aim of this work is that explore the influence of boron, zirconium, and tellurium on the impact toughness of the mentioned steel. Change of impact toughness, depending on the chemical composition of the steel is simulated with the Matlab program

Radiological and physico-chemical characterization of red mud as an Al-containing precursor in inorganic binders for the building industry

The potential re-use of red mud in the building and construction industry has been the subject of research of many scientists. The presented research is a contribution to the potential solution of this environmental issue through the synthesis of potential construction materials based on red mud. A promising way of recycling these secondary raw materials is the synthesis of alkali-activated binders or alkali activated materials. Alkali-activated materials or inorganic binders based on red mud are a new class of materials obtained by activation of inorganic precursors mainly constituted by silica, alumina and low content of calcium oxide. Since red mud contains radioactive elements like 226Ra and 232Th, this may be a problem for its further utilization. The content of naturally occurring radionuclides in manufactured material products with potential application in the building and construction industry is important from the standpoint of radiation protection. Gamma radiation of the primordial radionuclides, 40K and members of the uranium and thorium series, increases the external gamma dose rate. However, more and more precedence is being given to limiting the radiological dose originating from building materials on the population these days. The aim of this research was to investigate the possible influence of alkali activation-polymerization processes on the natural radioactivity of alkali activated materials synthesized by red mud (BOKSIT a. d. Milići, Zvornik, Bosnia and Herzegovina) and their structural properties. This research confirmed that during the polymerization process the natural radioactivity was reduced, and that the process of alkali activation of raw materials has an influence on natural radioactivity of synthesized materials

Manual for use of Al-containing residues in low-carbon mineral binders

Our society can no longer be imagined without its modern infrastructure, which is inevitably based on the use of various mineral and metallic materials and requires a high energy consumption. Parallel to the production of materials, as well as the production of electricity, huge amounts of various industrial and mining residues (waste/by-product) are generated and many of them are sent to landfill. The European Union (EU) aims to increase resource efficiency and the supply of ”secondary raw materials“ through recycling [1], inventory of waste from extractive industries [2], and waste prevention, waste re-use and material recycling [3]. Much of the industrial and mining waste is enriched with aluminium (Al) and therefore has a potential to replace natural sources of Al in mineral binders with a high Al demand. However, the use of industrial residue in mineral binders requires an extensive knowledge of its chemical composition, including potential hazardous components (e.g. mercury), mineral composition, organic content, radioactivity and physical properties (moisture content, density, etc.). This manual addresses the legislative aspects, governing the use of secondary raw materials in construction products, description of the most common Al-containing industrial and mining residue (bauxite deposits, red mud, ferrous slag, ash and some other by products from industry), potentiality for their reutilisation and its economic aspects, potential requirements/barriers for the use of secondary raw materials in the cement industry and a description of belite-sulfoaluminate cements, which are a promising solution for implementing the circular economy through the use of large amounts of landfilled Al-rich industrial residue and mining waste cement clinker raw mixture. This manual was prepared by partners of the RIS-ALiCE project. It provides a popular content, which targets relevant stakeholders as well as the wider society. Moreover, it offers education material for undergraduate, master and PhD students.Other links: [http://www.zag.si/dl/manual-alice.pdf