A zinc-pigmented corrosion protection primer is being used by the automotive industry. This state of the art “first generation” type coating is now applied on a chromate-free pre-treatment. It has been further developed and is now called the “second generation” corrosion protection primer. This new coating type has a higher thickness with double the amount of corrosion resistance and has a curing temperature suitable for BH-grade steels. The properties in corrosion, forming, welding and adhesive bonding together with the potentials for the automotive industry in using it will be presented from the viewpoint of a steel and automotive producer.

By depositing PVD coatings on already conventionally galvanized steel sheets novel zinc alloy coatings have been developed. One of the biggest advantages of PVD coatings lies in the broad choice of coating materials as there are no constraints due to chemical reactions between the substrate and the coating. This leads to a variety in the coating compositions. Accordingly, PVD processes enable customized solutions for various purposes. Magnesium on galvanized sheet steel has been identified as a very promising coating system. Corrosion performance is improved considerably while other properties like forming, joining and painting are comparable to or better than the untreated galvanized material.

The hot-dip coating process faces a particular challenge with the production of high-strength steels. The backdrop to this challenge in the case of the high-strength steels is the enrichment of alloying elements necessary to control the microstructure at the steel's surface. These elements diffuse to the strip surface during the annealing treatment in the furnace and affect the wetting action of the molten zinc. The hot-dip galvanizing of high-strength steels has been tested in numerous laboratory and field trials. New methods for improving zinc coatability have been developed around the world. A focal point of the work at ThyssenKrupp Stahl AG has for this reason lain in the development of a new generation of multiphase steels that achieve an optimum surface quality also in conventional hot-dip coating lines.

Recent investigations have shown that an iron oxidation / reduction process can improve the quality of the coated steels by decreasing the amount of external selective oxidation. This economical process can be made during heating by modifying the air/gas ratio of the direct fire furnace or in the rapid cooling section by air injection. A sensor allows measuring continuously the iron oxide thickness of the oxidized strip.

Whereas skimming is a well-known by-product of hot dip galvanizing, it has never been deeply investigated, neither well accounted for, by galvanizers. Physical reasons justify that the proper units, for the operating costs of skimming, are g/m2 or more generally weight per unit surface, instead of weight percentage of the loaded Zn. Indeed, with such a unit, results would largely depend on the average coating thickness. A stepwise regression analysis on skimming, produced daily on four industrial lines of Arcelor, shows that it is highly correlated to the line speed. Skimming costs will inherently increase with the line productivity for a defined thickness. The explanation of that fact is not fully clear because very low Zn oxide is found in the skimming which mainly consists of pure Zn. The wiping process is however suspected. Future work is required to try to establish a full modelling of the skimming production including Fe dissolution as well as the oxidation at wiping and the skimming practice.

An automation project has been realized to raise the capacity, the logistic and delivery performances, to reduce the workforce needed and to optimize the use of transport vehicles. This project comprises automatic tracking of all slab displacements, done by overhead cranes and other transport vehicles. It also contains algorithms to generate optimized slab displacement commands. The position tracking of outside transport vehicles is done by GPS. The optimization algorithms will be described in some more detail, as well as the results of the complete system.

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.

The 24th International Steelmaking Days of ATS (Association Technique de la Sidérurgie) took place on the 10th and 11th of December 2003 in Paris. More than 650 experts coming from 24 countries all over the world attended the congress. For flat products, 27 reports were presented and discussed concerning hot rolling, cold rolling and surface coating. The reports show that progress in hot and cold rolling technology requires close cooperation between production, research and development, as well as with the revamping team and the plant supplier. Highlights of the papers are measures for increasing the availability of the plant, optimization of yield and quality, cost-effective production and sustainability.

Carmakers face ever more frequently the phenomenon of spring-back after stamping, especially with new high strength steels (HSS and VHSS). Renault and Arcelor have been working together for many years on the formability and spring-back of VHSS. Recently, they aimed at establishing a method to optimize die shape in order to compensate for the spring-back after stamping. A method, named “Outifo” has been developed in order to obtain by simulation, from the initial CADs of the part and its referential stamped die, a CAD of a die with a modified shape. This allows the real stamping part, after forming and spring-back, to recover as closely as possible the geometry of the theoretical part defined by the designer.

The paper deals with the design of stainless steel exhaust manifolds, focusing on the development of high temperature ferritic grades and their forming capabilities related to the new forming processes, like bending and hydroforming. In particular, it is shown along the presentation, how a niobium stabilized 14%Cr grade can be used in replacement of austenitic grades in many situations of complex shaped manifolds thanks to its combined improved formability and its high temperature resistance up to 950°C. Finally, the authors present a “virtual” thermomechanical fatigue design approach, using a dedicated post processor, which would permit to optimize the design of the fabricated exhaust manifolds, and would lower the development cost and time by limiting both the number of prototype and motor bench tests and, finally, would reduce the risk of failure.