Innovative Stainless Steel Applications in transport ... - Euro Inox

Grade 1.4318 stainless steel was supplied to the DOLTRAC project in cold-worked
2H+C850 and 2H+C1000 conditions. Experimental hollow sections from 1.4318
2H+C850 strip were also manufactured for the project.
Table 3. Typical chemical composition of the DOLTRAC project 1.4318 heats (in weight %).
C S Si Mn Cr Ni N
0.025 0.001 0.49 1.21 17.5 6.8 0.120
Grade 16-7Mn
Compared to standard 18/8 grade, this type of austenitic stainless alloy is constructed on
the basis of a relatively low nickel content, for economic reasons – to minimise the
effects of nickel-price fluctuations. The final nickel content is kept as low as possible by
making chemistry adjustments to achieve the overall target characteristics, paying
particular attention to corrosion properties and austenite stability. This type of solution
usually involves developing steels with higher mechanical properties and meets design
requirements in most relevant areas, while exhibiting certain limitations in terms of
corrosion behaviour.
Recent developments in the low-nickel AISI 200-series alloys have led to a nickel
content of a minimum of 4 % in several load-bearing structural applications. However,
high-strength austenitic grades with extremely low nickel content, such as the
experimental 16-7Mn alloy used in the BUS project, may show a risk of delayed
cracking. Still, this experimental grade is included as a representative of the AISI 200
series of steels, to demonstrate their future potential (Table 4). Advances in alloy design
have recently led to the introduction of a “European” chromium-manganese stainless
steel, EN 1.4618, which is believed to have significant potential in, for example,
transport applications.
Table 4. Typical chemical composition of the BUS project 16-7Mn heats (in weight %).
C S Si Mn Cr Ni Mo Cu N
0.051 0.001 0.81 7.36 16.50 1.59 0.08 2.86 0.191
Grade 1.4003 (UNS 40977)
This is a 10.5 to 12.5 % ferritic stainless steel grade, with good mechanical, forming and
corrosion-resistance properties (Table 5). It provides the benefits of high abrasion-
resistance and wear-resistance and can be readily welded (not only in light thicknesses)
using numerous conventional and high-power techniques, such as MIG/MAG, GTAW,
LBW or resistance-welding techniques.
Grade 1.4003 is far more corrosion resistant than mild steel. It offers good durability
and low maintenance costs – even unpainted or uncoated in some applications. Painting,
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