Research and development
Technological progress by processors, increasing customer requirements and the competitive situation set new challenges for research and development at ThyssenKrupp Stainless. Working with our customers, our development centers come up with high-quality and innovative solutions.
In fiscal year 2005/2006, ThyssenKrupp Stainless AG invested €19.3 million in research and development throughout the group. To improve our products and processes, we have our own development centers both for stainless steel and for high-performance materials. Furthermore, there is close cooperation between the various development centers of the entire group. In cooperation with our customers, these competence centers come up with high-quality solutions.
New material concepts an attractive finishes for flat stainless steel
Continuing high prices for the alloying element nickel are creating an increasing need for less expensive material alternatives. For this reason we are looking closely into the production of raw material-saving, ferritic materials with market-capable properties. Various alloy composition and production concepts for this were developed in the past fiscal year. For example, targeted modifications were made to a nickel-free ferritic material to improve its processability by manufacturers of chemical process equipment.
A further material concept focuses on the use of high-strength steels based on two-phase materials using low amounts of alloying elements. In addition to lower alloy costs, customers can also save on material as the high strength allows a reduction in wall thickness. This group of materials is not very well represented on the market so far but is attracting increasing interest. The design of the material is carried out on computer using specially developed software.
In response to continuing high prices for raw materials, especially nickel and molybdenum, new materials have been developed which offer comparable corrosion resistance and high strength with lower input of these alloy materials. This development is being accompanied by substantial investments into a further improved melting metallurgy at the Terni site.
One focus of innovation in the Stainless segment is the development of new surface finishes offering enhanced appearance and functionality. One example is Nirosta GritLine, which is comparable with the already established Rolled-On finish marketed by ThyssenKrupp Mexinox in North America. Both are embossed finishes which resemble popular polished finishes. The unbroken surface offers aggressive media less opportunity for attack and allows the use of less expensive base materials in many cases.
The star among the new stainless steel finishes is the transparent coating SilverIce UV. It makes stainless steel surfaces less sensitive to fingerprints, more resistant to scratches and even easier to clean. It can be used to protect trim panels which have to meet high quality requirements. The product has already established itself successfully on the market. SilverIce UV won 2nd prize in the 2006 ThyssenKrupp Innovation Contest.
To enable us to meet customers’ increasing demands on surface quality, we have also further upgraded our automatic strip surface inspection facilities. All our surface inspection systems, consisting of numerous high-resolution video cameras, are now connected to a central company-wide quality database, where special programs analyze the results and correlate them with process data. This has enabled us to both further improve the quality of shipped products and increase process reliability with a reduction in production costs.
Prepared for tomorrow’s material requirements
Research progress was also made with our nickel and titanium alloys. Our development efforts into vacuum-melted nickel alloys for the growing aerospace, power generation, oil and gas markets were continued. The aim of ThyssenKrupp VDM is to expand into highly profitable segments of the nickel alloy market. Above all this includes the so-called superalloys, i.e. high-performance materials displaying special corrosion and heat resistance properties.
These superalloys are used for example for rotating turbine parts in aircraft engines and land-based turbines. Wide-ranging material development programs are looking into the behavior of superalloys in steam power plants operating at temperatures of 700ºC, much higher than conventional thermal power plants.
For this reason, ThyssenKrupp VDM is also investing in a new forge to widen our range of products for the aerospace industry. This will enable us to gain additional approvals in the future, including for rotating turbine parts in jet engines.
Our development efforts in the fuel cell area were also continued. The properties of alloy Crofer 22 for use in fuel cells were further enhanced. To exploit the full potential of this material, corrosion in fuel cells was investigated in more detail. Tests under specific operating conditions are being continued in cooperation with customers.
As early preparation to meet the material requirements of the future, ThyssenKrupp VDM is taking part in COORETEC, a program sponsored by the German Ministry for Economy and Labor pursuing the development of 700-degree steam power plants. The higher temperatures compared with conventional power plants call for new material concepts, which represent potential fields of application for nickel alloys. Under the program, ThyssenKrupp VDM is investigating corrosion and oxidation behavior and determining long-term mechanical properties. The materials Alloy 617/Nicrofer 5520Co and Alloy C-263/Nicrofer 5120CoTi will be tested in particular.
Development work in the titanium area was concerned with both conventional applications and emerging products.
For instance, titanium sheet which is roll-clad with aluminium and subsequently reactive-annealed for use at higher temperatures has passed its first trials in Bugatti exhaust systems. The roll-clad coating acts as a diffusion barrier to prevent the oxidation which is otherwise usual at these high temperatures. A further improvement to this composite material is planned to increase its elevatedtemperature and creep strength. Together with Volkswagen AG a modification of the titanium alloy has been developed which is currently in trial production. In combination with the diffusion barrier this system offers a new field of application for these temperatures.
The use of the tailored blank concept to widen the range of sheet sizes producible from titanium strip looks promising after initial stamping tests at a manufacturer of plate heat exchangers. The concept could also be extended to tailored blanks with different thicknesses and different titanium grades.