Alloy design is a challenging multi-objective optimisation problem, which consists of finding the optimal processing parameters and the corresponding chemical compositions to achieve certain pre-defined mechanical properties of steels. In this paper, we combine fuzzy modelling and Particle Swarm Optimisation (PSO) to address the multi-objective optimal alloy design problem. An adaptive weighted...

It is well known that inclusions and clusters, which are formed in liquid steel during ladle treatment, have harmful effects on the casting process (clogging problems) as well as on the final mechanical properties of a steel product. Especially, steels deoxidized or alloyed with rare earth metals (REM) are difficult to produce due to the high tendency of REM-oxides to form cluster and clog the ...

Developments in computer-aided engineering and the rapid growth of computational power have made simulation-driven process and product development efficient and useful since it enables detailed evaluation of product designs and their manufacturing processes. In the context of a sheet metal component, it is vital to predict possible failure both during its forming process and its subsequent usag...

One of the attractive low activation steels is the austenitic Mn-Cr steel from the view point of waste disposal because of few long-lived nuclides. In this paper, three types of Mn-Cr austenitic steels were fabricated by vacuum induction furnace. Then plates with 10 mm thickness were fabricated by hot-rolling. The physical metallurgy of these steels was studied by the corrected Schaeffler diagr...

Experimental results and explanations for the transition temperature from upper to lower bainites in carbon steels containing from 0.20 to 1.80 wt%C were presented metallographically and kinematically. The experimental results are summarized as follows: I) Lower bainite is not formed in steels with less than 0.35 wt%C and no transition from upper to lower bainite occurs. 2) The transition tempe...

Austenitization is an inevitable occurrence during the heat treatment of steels. Despite this consideration, less attention has been paid so far to the study of the formation of austenite as compared with the vast amount of research on its decomposition. That is because the steel properties depend basically on the transformation processes following austenitization. However, the initial austenit...

Carbon steels are widely used in the oil and gas industry from downhole tubing to transport trunk lines. Microbes form biofilms, some of which cause the so-called microbiologically influenced corrosion (MIC) of carbon steels. MIC by sulfate reducing bacteria (SRB) is often a leading cause in MIC failures. Electrogenic SRB sessile cells harvest extracellular electrons from elemental iron oxidati...

Metastable ω phase is common in body-centred cubic (bcc) metals and alloys, including high-alloying steels. Recent theoretical calculations also suggest that the ω structure may act as an intermediate phase for face-centred cubic (fcc)-to-bcc transformation. Thus far, the role of the ω phase played in fcc-bcc martensitic transformation in carbon steels has not been reported. In previous investi...

As the upper temperature for use of reduced activation ferritic/martensitic (RAFM) steels is presently limited by a drop in mechanical strength at about 550°C, Europe, Japan and the US are actively researching steels with high strength at higher operating temperatures, mainly using stable oxide dispersion. In addition, the numerous interfaces between matrix and oxide particles are expected to a...

Three low-carbon bainitic steels were designed to investigate the effects of Cr and Al addition on bainitic transformation, microstructures, and properties by metallographic method and dilatometry. The results show that compared with the base steel without Cr and Al addition, only Cr addition is effective for improving the strength of low-carbon bainitic steel by increasing the amount of bainit...