TK Stainless

stainless steel
speCiaL sTainLess sTeeL MeeTs risinG DeManDs For
eXhausT sysTeMs
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MaGaZine
“With NIROSTA 4607, ThyssenKrupp Nirosta is meeting increasing customer
demand for high-quality yet cost-efficient materials,” says Stefan Schuberth,
head of technical product service at ThyssenKrupp Nirosta. “With nickel
prices very high at times, manufacturers of auto exhaust systems, who already
make extensive use of stainless steel, have been under severe price pressure.”
The solution: As part of an extensive innovation strategy aimed at saving
raw materials, experts from the company developed a new ferritic material
(NIROSTA 4607) that displays equivalent corrosion resistance properties to the
previous standard material NIROSTA 4301, which contains nickel. Thanks to its
specific composition, the new material costs significantly less. ThyssenKrupp
Nirosta developed this product to market maturity and is now offering it for the
first time on the European market.
“The new material contains no nickel,” explains Schuberth. “So
unlike the nickel-containing stainless steels in widespread use it is completely
independent of nickel prices.” What also makes NIROSTA 4607 so special is
that it is the first European ferritic stainless steel that can match the corrosion
resistance of NIROSTA 4301, which it achieves not only without nickel but also
without molybdenum, another very expensive alloying element. “This allows
our end customers to make major cost savings,” says Schuberth. The new
material can be used wherever the formability of a ferritic stainless steel is
adequate.
But as well as being cost-efficient, this new material has to satisfy
increased requirements: In particular, new engine generations with advanced,
higher-efficiency exhaust technologies generate far higher corrosive and
thermal loads than their predecessors. “The challenge lay in making the
material cost-efficient for our customers while still meeting their high quality
requirements,” says Dr. Gabriele Brückner, head of materials technology at
ThyssenKrupp Nirosta in Düsseldorf-Benrath. “The good solution we have come
up with is primarily down to the expertise and experience of our development
department.” The material delivers not only high corrosion resistance which is
the equal of many commonly used higher-priced materials, but also good hightemperature
strength comparable with the proven high-temperature material
NIROSTA 4509.
These properties make it particularly suitable for use in the hot frontend
areas of the exhaust system. Thanks to the addition of other chemical
elements, the material is also weldable by all methods. “The combination
of high-temperature strength and corrosion resistance is ideal for exhaust
systems with long service lifetimes,” says Dr. Gabriele Brückner. In developing
the material, the company demonstrated its ability to respond quickly and
effectively to changing demands. Weiß: “Thanks to its properties and costefficiency,
we expect our new material to meet with wide acceptance by the
market.“ ---
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