Cover Caption: The cover image is a schematic for the utilization of hot metal up to 75% of the charge into an industrial scale 150 ton/ch DC-EAF. The steelmaking process parameters are significantly changed with the addition of large amounts of high carbon containing hot metal into the furnace. Oxygen lancing, power input, and tap-to-tap times are some of the essential process parameters that require optimization. For further details see the article by Il Sohn and co-workers on page 302.

The influence of small casting speed variations (715–735 mm min⁻¹) on the metallurgical length in steel continuous casting is numerically investigated. The numerical simulations are based on an Eulerian two-phase solidification model. For a given casting configuration, the effects of strand surface bulging, shrinkage feeding, and mechanical softreduction are considered in different simulation cases.

A mathematical model for the combined top and bottom blowing VOD refining of stainless steel is proposed. It is applied to 20 heats of 409L-grade steel refining in a 120 t VOD vessel, good results are obtained. The influences of the related factors and the optimization of blowing technology are examined from the model predictions.

A novel approach, which combines CFD-modeling and regression analysis is applied to examine slag droplet distribution and generation rate with different steel flow velocities. Three phase CFD calculations are carried out for determining the shape of the distributions and then Rossin–Rammler–Sperling distribution function is fitted to the data, which enable estimating the birthrates of the emulsified droplets.

Cementite is commonly failure causing phase in steel alloys, in particular in high manganese steel. The new ladle treatment technology is used for treating molten Hadfield steel by iron base modifiers with (Mg +CaSi). Pseudo-eutectic is forming between austenite and cementite as a result of the ladle treatment. A new eutectic is well dispersed throughout the austenite matrix, and accordingly supplies the steel with high toughness accompanied with excellent abrasion resistance without high energy heat treatment process.

Inter-critical annealing treatments are conducted on hot-rolled weathering steel aiming at improving its mechanical and formality properties by generating DP microstructures. The developed DP-weathering steels achieve 23–25% increase in strength compared to the ferrite/pearlite weathering steel. Generating DP microstructure improve the formability to a large extent and accelerate the nucleation of the characteristic (atmospheric corrosion resistance) FeOOH layer.

The relationships of the compounds in the Mg–Ti–Al–O system in equilibrium with molten iron are clarified at temperatures ranging from 1873 to 1973 K, and the thermodynamic calculations are conducted in avoiding Al₂O₃ or spinel MgAl₂O₄ formation and for inclusion control. It is shown that the equilibrium relations between those compounds and the composition of solutes in steel at 1973 K.

The present study shows that good combination of high tensile strength and relatively high ductility of a microalloyed carbon steel have been attained by quenching–partitioning–tempering process. The experimental results show that the sample partition-tempered for 30 s exhibits best comprehensive mechanical properties, which result from the integrated effect of carbide precipitation, conservation of certain amount of retained austenite and softening of the martensite matrix during the partition–tempering process.

The manufacturing of micro lubrication pockets in stainless steel AISI 304 by hot micro-coining is investigated conducting finite element simulations and complementing experiments. Suitable process parameters and process limits are determined in this work. Process limits occurred for the coining of high strength materials at low process temperatures due to plastic deformation of the die.

In this study, a classification model is developed for real-time prediction of various kinds of mill scales at typical hot rolling mill (HRM). In order to obtain input data, the automatic surface inspection system (ASIS) is used together with its classification model. Thereafter, novel procedure is introduced for further boosting of the accuracy of predictions by the use of hybrid classification concept.

M₂₃C₆ particles size, number and dissolution velocity were deduced for tempering of a X20 steel at 800 to 550 °C. The dissolution of small particles increases the particle spacing for above one order of magnitude more than particles coarsening. By creep tests above 550 °C, particles spacing and creep rate are increased significantly by dissolution of small particles.

Composition evolution and number density of oxide inclusions in austenitic stainless steel during continuous casting are demonstrated by plant data as well as mathematical modeling. Origin of the inclusions is argon oxygen decaburization (AOD) slag, and the inclusions grow by subsequent oxide formation due to decrease of solubility limit of O, Al, Mn, Si, etc, during casting. A simple mathematical model is presented to account for the composition evolution.

A novel method to synthesize Mo₂NiB₂ boride cermet coating on Q235 steel substrate, consisting of Mo₂NiB₂-type ternary boride as a reinforced phase and a γ-(Fe, Ni) base binder, is realized with laser cladding technique. The wear resistance of the Q235 substrate is greatly improved. As compared to 304 stainless steel, lower corrosion rate is obtained for the coating and pitting corrosion disappeare in particular.

Hot metal additions into a 150 ton DC-EAF is studied. 1700 kWh of accumulated power consumption is decreased for every ton of hot metal utilized. Oxygen lancing practices is modified with hot metal additions in the EAF without increasing the tap-to-tap times. At hot metal additions of above 0.6, the decarburization rate linearly increases with oxygen lancing.