This paper addresses issues of material flows in a selection of modern steel plants,especially the generation of wastes, from a social sciences perspective. I analyse keyfactors structuring waste management decisions through the case of “problem” wastesarising at a steel company’s plants. I discuss how some materials come to be construed asmore problematical than others from a material and technological point of view, but alsoby taking into account organisational and legislative issues, in order to show that theconstruction of the “waste” category needs to be envisioned as resulting from a matrix ofsocio-material causes.

This paper presents a probabilistic method for fatigue life estimation within thefrequency domain for structural elements subjected to multiaxial random loadings.Multivariate Monte Carlo Simulation is used to account for the correlation between thestress components and their different probability of occurrence and, moreover, enablesstochastics during damage analysis to be allowed for and, at the same time, uses anysuitable, material dependent multiaxial fatigue criterion known from the time domain.Comparison of the evaluated fatigue damage with experimental results from vibration testson a demonstrator, chosen from common application fields in the automobile industry, showsgood correlation.

Segregation is an important phenomenon which heavily affects the final mechanicalproperties of steel products. The presence of several complex physical phenomena resultingin final segregation pattern in as-cast products makes the quantitative prediction ofmacro-segregation for industrially relevant casting processes extremely difficult. In thepresent work, a reliable prediction of important rolled product quality (in terms ofmechanical and Charpy impact properties) which are linked to segregation is achieved forplate rolled pipeline steels by exploiting data related to the as-cast structure andcaster operational data (including casting machine condition) through the application ofneural networks. In particular, a hierarchical approach is proposed for the prediction ofthe Charpy Impact Value, in order to reflect the physical link between this quantity andthe Ultimate Tensile Strength. The neural predictor has been developed by exploiting realindustrial data and its performance can improve through time by enlarging the databasethat is used for its training.

A novel rheo-rolling process for producing A356 alloy sheet was developed. The influenceof parameters on the microstructure of A356 alloy sheets was investigated. The eutecticfraction and primary α globule size increase with the increment in theroll speed. The globule size and eutectic fraction of A356 alloy sheet increase with theincrement in the casting temperature. The primary α globule sizedecreases and the solid fraction increases with the increment in vibration frequency from30 Hz to 80 Hz. With a roll speed of 0.069 m.s-1, a casting temperature of 660°C, and a vibration frequency of 80 Hz, A356 alloy sheet with a cross-sectionsize of 4 × 160 mm was prepared. The microstructure is mainly composed of fine sphericalor rosette α globules, and the average α globule size is20.5 μm. The ultimate tensile strength of the A356 alloy sheet was 260MPa, and the elongation to failure was 7.9%, which were 2.5 and 3.7 times greater thanthose of the as-cast material.

Formation of deposits inside the submerged entry nozzles used in continuous casting ofespecially low-silicon Al-killed mild steels may often cause nozzle clogging and castingdisorder. Technological experience has shown that the application of Ca-treatment beforecasting usually eliminates this phenomenon. In order to understand deposit formation andthe way it can be avoided, we have carried out detailed mineralogical analyses of thedeposits formed on the inner and outer surfaces of the nozzles by different techniques.Results obtained from deposits formed during the casting of only Al-killed andsubsequently Ca-treated steels show that the results obtained from deposits formed duringthe casting of only Al-killed and subsequently Ca-treated steels show that the aluminainclusions carried to the wall of the nozzle form the matrix of the dangerous deposits.Application of Ca-treatment resulted in mostly liquid aluminates compounds and almostnegligible deposit formation. The outer surface of the nozzles however showed similardeposit formation because of possible reoxidation of dissolved aluminium.