Duplex stainless steels are often used today in the oil and gas industry because of theirhigh strength and good corrosion resistance. New developments in arctic conditions and athigh pressure require the qualification of these materials at very low temperatures. Thispaper will present the results of an extensive test program dedicated to assessing thelow-temperature behavior of various heavy-wall duplex stainless steel forgings, hotisostatically-pressed (HIP) connectors and hot extruded pipes at temperatures down to –60°C. Several welding processes were also evaluated. The implications for thedesign of duplex stainless steel production facilities will be discussed.

In order to explain and simulate the behaviour of real, complex gas-solid reactive systems, we developed a new kinetic model which describes the coupled phenomena of chemical reaction, diffusion, heat transfer and porosity evolution. The model was successfully applied to the hydrofluorination of uranium dioxide. The difference in reactivity between two dioxides has been related to their initial pore structure and its evolution.

The major objective of this research is to develop a 3-D FEM simulationtechnique in order to analyze the deformation behavior of surfacedefects on hot rolling. The developed technique will be applied toquantify the relationship between rolling condition and the processparameters, and the rolling pattern will be tested to verify and validatethe simulation technique. This technique will allow us to quantify theshrinkage of slab width at the head and tail, width spread after thehorizontal rolling, dog-bone shape, position change of the slab corneras the slab is being rolled, strain distributions. And the shape changeof surface defects in hot rolling was investigated using the 3-D rollingsimulation technique. The proposed prediction method of surfacedefect can be utilized to make defect free products in rolling.

Frequently, it is desired to preserve the original tones of copper, brass and bronze surfaces which are used in decorative areas. This can be achieved by applying clear protective coatings, acting as weather barriers and surface protections against mechanical aggressions. The performance of two clear coatings and a hard coating is evaluated, using a linear scratch test and abrasion tests. The hybrid sol-gel coating greatly improves the wear resistance of brass. The corrosion-resistant varnish tested has very poor wear resistance. Too thin and porous hard-coating layers have poor corrosion and abrasion resistance. The hybrid sol-gel coating gives the best compromise in terms of aspect, properties and cost.

The paper presents a review of the current knowledge on the influence of gaseous atmospheres, and primarily ambient air, on fatigue crack propagation in metallic alloys. Experimental evidence of the effect of exposure to ambient air or any moist environment on fatigue crack propagation in steels is first proposed. The different interacting processes are analyzed so as to clearly uncouple the influence of the various factors on crack growth resistance. Two distinct mechanisms are identified : the adsorption of vapour molecules and hydrogen assisted fracture at crack tip.

The efficiency of automatic flatness control systems in hot rolling mills is based mainly on the capability of the installed instrumentation to provide accurate flatness measurements, on accurate prediction models, and on the selection of an optimum control concept. BFI, together with Thyssen Krupp Stahl, has recently developed a new topometric flatness measurement device (called TopPlan) and advanced flatness control strategies (providing time delay compensation, systematic analysis of shape errors and exact distribution of shape coefficients to be controlled by actuator sets) that offer advantages over conventional techniques and lead to significant improvements in hot rolling processes and strip shape. The present article aims to demonstrate the principles and advantages of these technologies.

The Australian Pilbara blend lump ore, which entered the Chinese market in 2007, is aspecial blending ore. To master its behavior and effect in a BF adequately, themetallurgical properties and high temperature reactivity of the Pilbara blend lump ore andsix other kinds of lump ore were researched. The reasonable proportion and mixing patternof the Pilbara blend lump ore was studied by carrying out softening and dropping propertytests, and this provides technological support for practical production.

Mechanisms of deformation in an age-hardenable Ni-Mo-Cr alloy containing large precipitates of the coherent ordered phase were investigated. The dominant deformation mechanism in the examined alloy depended on the applied amount of strain: for low strains micro-twinning within the ordered precipitates and dislocation slip in the matrix prevailed; at higher strains the f.c.c. twinning became the major deformation mechanism. Micro-twinning within the ordered phase was size related - micro-twins occur in large precipitates at relatively small strains. Twinning within the ordered precipitates may occur in all possible twin systems. Ten out of twelve possible twinning systems lead to the formation of true twins, and the long range order is preserved in the twinned regions. Formation of shear bands at high strains destroys the long range order.

A new technology for lubricating the work rolls during hot rolling has been successfullytested in the finishing mill of ArcelorMittal Dunkirk. This new technology allows sprayingvery low quantities of pure oil on the work rolls to reduce the rolling forces by up to20% and with an increased efficiency of 50% compared with emulsions. The lubricant was apure natural oil without any additives.

The growth velocity during solidification of an undercooled melt of a Co-Cu alloyprocessed by electromagnetic levitation was measured using a high speed video camera.Applying a model of local non-equilibrium solidification, theoretical predictions ofdendrite growth velocity and dendritic growth radii are compared with high-accuracymeasurements of the growth kinetics. As the undercooling ΔT reaches a critical valueconsistent with the dendrite growth velocity being equal to the atomic diffusion speedVD in bulk liquid,ΔT =ΔT(VD),the velocity-undercooling relationship exhibits a break-point. A distinct change in thedendritic growth mechanism exists with the onset of complete solute trapping andchemically partitionless solidification of the core of the main stems of the dendritesoccurs. A complete transition to the thermally controlled growth of dendrites occurs atΔT =ΔT(VD)that leads to essential changes in the microstructure of dendritic patterns The phenomenonof dendritic fragmentation in Co-Cu melts, solidifying at ΔT <ΔT(VD),is discussed.

This Bessemer lecture is a unique occasion for the author to look at some of the issues to which he has been close professionally, with a perspective spanning over three centuries, something that one does not so often have the leisure to do in the Steel Industry. The author speaks first briefly about Sir Henry Bessemer and the dynamic 19th century of which he was such an active player. Then the author skips over 100 years to 1970 and recollects some of the endeavours and achievements of the Steel Industry of the late 20th century, which he witnessed at first hand. There were deep changes of course, but also intriguing continuity with Bessemer's time. Finally, as Technological Forecasting or rather Prospective, the author projects what kind of path the Steel Industry might tread in the future and why. This is done from the viewpoint of an engineer and based on the idea that the core of the Steel Technology is the archetype of a Cumulative Technology rather than a mature, saturated and somewhat passé activity.

During the Bronze and Iron Ages, seven metals and about ten alloys were employed in the Western world. The manufacturing processes used by craftsmen (casting, hammering, finishing) for the copper base alloys are examined and discussed from the archaeological and metallurgical points of view. Some results obtained in Burgundy, dating from the 1st century BC to the 3rd century AD, permit tentative conclusions to be drawn regarding workshop organization and mass production.

Based on the balance equations of mass, partial mass,momentum and thermal energy, the pyrolysis processof non-coking coals using a counter-rotating twin screwreactor (TSR) is modelled by means of commercial CFDcode PhoenicsTM. In favour of good convergence of themathematical solution, a structured, cylindrical-polar gridis chosen. Variable filling and intermeshing degrees aretaken into account by blocking numerical cells in gasdomain and intermeshing domain instead of performingtwo-phase calculations in a body-fitted co-ordinate system.Viscous behaviour of the granular coals is expressed bymeans of a generalised Newtonian fluid and chemicaldecomposition is implemented with aid of distributedactivation energies.

Improvements have been made to slab, bloom, billet and thin slab caster secondary cooling systems giving better control of strand surface temperature and quality. This has been achieved by a combination of laboratory-based tests of spray characteristics and heat transfer coefficient (htc), innovative mathematical modelling and detailed on-plant measurements of temperatures and spray conditions.

This paper is mainly devoted to the presentation and the illustration of chemical microananalysis methods. Four basic techniques will be successively presented: the energy dispersive X-rays spectroscopy (EDS), the wave dispersive spectroscopy of X-rays (WDS), the electron energy loss spectroscopy (EELS) and the Auger spectroscopy (AES). For each of them, the limitations and advantages will be presented.

Les aciers inoxydables austénitiques non sensibilisés peuvent subir dans l’acide nitrique un type de corrosion intergranulaire (CIG) particulier. Un modèle d’estimation de la durée de vie de ces matériaux dans ces milieux est proposé. Il reproduit de manière fiable les cinétiques de corrosion obtenues expérimentalement.

In the last few years, CPM developed a first generation of charging model for coke ovens to improve the uniformity of oven filling and to reduce charging emissions. A new charging model has been recently built to simulate all kinds of charging process with 3, 4 or 5 charging holes and to obtain a more reliable representation of the levelling operation. More particularly, coal accumulation in each compartment of the leveller bar is represented, in order to have a better idea of the gas free space during the levelling operation. By using this model, it is now possible to suppress or reduce coal accumulation in the oven free space during the levelling operation and to obtain a constant and uniform coal profile at the end of charging, without gas emissions.

Industrial trials were carried out at the ArcelorMittal Isbergues slab continuous caster with the HJN (Hollow Jet Nozzle) previously developed at CRM at the pilot stage. This nozzle allows the addition of fine metallic powders in molten steel right before its solidification. These tests showed the possibility to implement the nozzle in an industrial stainless steel slab caster. It was observed a full melting of the injected elements (Fe and Fe-Ti), a homogeneous distribution of titanium element in slabs and a drastic improvement of the addition yield of titanium.

Physical model experiments were performed to clarify the influence of orifice configuration on the volumetric mass transfer coefficient during ladle purging. Bubble behavior was recorded by a high speed video camera in the present study. And carbon dioxide desorption from an aqueous NaOH solution was used to measure the volumetric mass transfer coefficient. It is found that bubbles for multi-hole orifice are generally smaller than those for 1-hole orifice. However, when the hole distance in the multi-hole orifice is too short to avoid bubble coalescence, large bubbles will be formed. It is shown that there is a decreasing tendency of the volumetric mass transfer coefficient when the hole diameter increases. The volumetric mass transfer coefficient firstly increases with increasing the hole distance and hole number. Thereafter, it remains approximately constant with further increase in the hole distance and hole number.