An experiment of continuous casting with ultra-high frequency electromagnetic field was carried out at No. 4 commercial caster at Kobe Works. It was confirmed that the durability of a slit mould was sufficient for long casting, and meniscus level was controlled precisely enough for stable casting by the level control technology using the inductance change in the magnetic system. The improvement of billet surface quality and the lubrication between the mould and the solidified shell are discussed.

In September 1998, the Sollac Florange HSM started up its second reheating furnace, with nearly the same size and thermal power as the first furnace built in 1983. This equipment has introduced new techniques, such as pulse width modulation on lower zones in order to control thermal power, or gas characteristics fine tuning with the correctometer using a furnace with only one burner, etc. Using two furnaces instead of one and a higher reheating capacity means some significant changes for the other tools of the HSM.

In May 1998, Muroran Works installed a near-net shape casting and compact high reduction (NCR) process in its steelmaking plant. The No.3 continuous casting machine was rearranged to cast middle cross section blooms, and a reheating furnace and a 2-passes high reduction breakdown mill were newly equipped. No.3 CCM casts square 220 mm mould size blooms and the breakdown mill reduces their cross section to square 162 mm. This combined process improved the quality of the cast billets and achieved high productivity.

Raman microspectrometry is particularly suitable for the study of artefacts surface. This article outlines the advantages of this vibrational technique. Its capability for identification is illustrated by applications on wall paintings and dyed textiles, and their historical implications are mentioned.

This paper describes innovative solutions developed by VOEST-ALPINE Industrieanlagenbau (VAI) for bar and wire-rod mills and concerning mechanical equipment as well as automation systems. Among them, the Precision Rolling System (PRS) was first implemented at Chaparral Steel (USA) and the Minimum Tension Control is applied at BMZ (Belarus). Benefits are: improved product quality, greater mill availability, increased flexibility and productivity.

A neural network model, trained by a genetic algorithm, has been developed to study the thickened ends of the pipes rolled by means of two stretch-reducing mills. The forecasting of the model showed a good performance that avoids other complicated developments based on precise structural approaches that generally take a great amount of elaboration time. The neural network can be applied to build an automatic procedure for the definition of the production parameters to minimize the discarded material of the pipe that is not in the limits imposed by the geometrical specifications.

For a HIP operation, conventional control of the process variables (T, P) is the current mode used. The process variables follow a prespecified trajectory (schedule) assumed to lead to the final quality of product. A second mode is advanced control, where on-line measurements of a product state variable enable to monitor the evolution of the product variables and if necessary to compute corrections to the schedule in order to obtain the desired quality of the final product. HIP advanced process control requires continuous monitoring of the sample density during all stages of the process and the on-line identification a process model. To this end, a dilatometer has been built for in situ monitoring densification during a HIP operation, the Ashby process model has been validated and on-line identification has been demonstrated. It is shown that advanced process control of a HIP operation can be performed in two steps : on-line identification of the process model and subsequent process path replanning. The first step can only be performed during the process variables plateau of the preset temperature-pressure cycle, and process path replanning consists of a new temperature-pressure plateau.

The understanding of the molecular aspects of adhesion needs the determination of the molecular order of macromolecular chains at the polymer/metal interface. Thin supported polymer films are studied by FTIR reflectance analysis (IRRAS). It is shown that the development of specific acid-base interactions at the interface is able to strongly organize and order macromolecular chains at the vicinity of the interface. Microstructural parameters of the polymer are shown to influence both interfacial organization and adhesion.

Laser irradiation may alter the colour of certain pigments used in artworks. Owing to the increasing use of lasers in artwork conservation, this problem becomes extremely crucial especially in the case of a polychromy covered by environmental encrustation. X-ray diffraction analysis and optical microscopy were used to study the crystalline structure of selected irradiated pigments in order to identify the changes that take place upon laser irradiation. Two representative pigments were studied, cinnabar (HgS) and lead white (Pb(OH)2 2PbCO3). The results revealed a change in the crystalline phase or chemical composition, respectively, which can be barely detected owing to its superficial character, which is of a sub-micrometer scale.

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.

To reduce roll wear and chatter vibrations in its hot strip mill, Eko Stahl carried out roll gap lubrication trials. The trial equipment, the lubricant and the trials themselves are described. Rolling force and consequently electric energy consumption were reduced by 8 to 34 % . The automation system reacted without difficulties to sudden rolling force changes. Three types of torque changes due to roll gap lubrication have been observed. Chatter vibrations have been suppressed efficiently during lubrication. Roll wear decreased. Strip thickness and profile tolerances were affected positively, other quality parameters did not change significantly.

"Martensite-retained austenite" constituents play an important role on Heat Affected Zone (HAZ) toughness in the welding of structural steels. The influence of thermal cycles - especially in the case of multipass welding - and of steel composition on the presence of such constituents is discussed here. Fracture initiation mechanisms related to these constituents are also examined.

The Mardyck hot-dip galvanizing line began operations on July 2, 1998. The line is devoted to supply the very demanding market of the automotive industry. The main products have pure zinc or zinc-iron coatings and correspond to steels with a wide range of mechanical properties. The first tons for unexposed parts were produced less than one month after the start-up of the line, and tons suitable for exposed parts as early as the beginning of October.

Ferritic warm rolling associated with cold rolling and annealing should be a promising and cost effective route for the production of DQ and DDQ qualities of thin strip. In the case of non-recrystallization warm rolling, warm and cold rolling contribute both to the development of the work-hardened structure and of the texture before annealing. Laboratory simulations have tried to determine how flexible this processing route could be. For a given total ferritic reduction, the cold rolling texture and the recrystallized grain size depend on the fraction of this reduction which is made by warm rolling. The final texture and the mechanical properties are however relatively insensitive to this fraction.

The instrumentation of an industrial vacuum arc refining furnace (VAR process) has allowed for the first time to visualize the electric arc during the remelting of a zirconium alloy. This device, recording fast video observations in synchronization with the high frequency voltage changes of the arc, has been applied to the study of the behaviour of the arc and of the transfer mechanisms of the liquid metal to the ingot. Results are given for current densities of about 10 to 20 A/cm2 and arc lengths smaller than 6 cm.

This paper describes how an optimization of the rolling conditions (roll lubrication, strip chilling) and the use of new roll qualities on the 2050 mm hot strip mill at Iscor Vanderbijlpark, allowed to realize the full potential of HSS rolls. Based on development work and laboratory studies on oxidation behaviour, these improvements benefit both to Hi-Cr and HSS rolls. The full implementation of HSS in stands F1 to F4 during year 2000 will allow to increase the mill availability by eliminating the intermediate roll change and reduce the work load in the roll shop.

The objective of the study is to determine the influence of forming on the adherence properties of sheet steel laminates. Drawing is then decomposed in different deformation modes: stretching (or biaxial tension), plane strain tension, uniaxial tension and shear deformation. Two adherence tests are used -the torsion shear test (napkin-ring) and the wedge test - in order to evaluate the metal/polymer adhesion before and after deformation.

It is economically important for manufacturers of high-temperature machines to be able to measure creep damage so they can predict residual service life more accurately. This paper describes and refines an image analysis method for evaluating creep damage in laboratory test pieces. It is a preliminary study of how to extract relevant information for damage measurement by cavities counting. Grain boundary extraction, which is directional information, is the major question to be overcome before measurement can be automated. The search for a crest-line extraction filter by the Canny method has led to the development of a directional wavelet transform filter. The results of this innovative filtering method are applied here.

With the aim of enhancing coating quality control during the galvannealing process, an on-line optical image acquisition sensor has been developed at "Centre de Recherches Métallurgiques" , Belgium.In the galvannealing process, the ζ phase surface density is a coating quality characteristic, and the on-line microscope, placed at 20 mm from the surface, grabs images on which ζ crystals can be clearly identified.The resulting images are then processed, and the results of the analysis can be used to adjust the process parameters in order to reach the desired coating characteristics (iron content, powdering) .

Steel and steel composite bridges share a rather small part of the total bridge market. Nevertheless they are unbeatable for very longspan, extremely slender and/or movable bridges or in the replacement and/or widening of existing bridges. The reduced weight of steel bridges and of the steel structure of steel composite bridges allows a quick and cost effective erection by launching, lifting, a combination of both, rotation and the like.