Structural Stainless Steel Designing with stainless steel

153 Pages·2017·17.52 MB·English

Structural Stainless Steel
Designing with stainless
steel
Ing. Maarten Fortan

Prof. dr. ir. Barbara Rossi
Department of Civil Engineering

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Outline
•  Corrosion resistance
•  Chemical composition and grades
•  Examples of structural applications
•  Grade selection
•  Material mechanical characteristics
•  Design according to Eurocode 3
•  Alternative methods
•  Deflections
•  Additional information
•  Resources for engineers
2
Section 1
Corrosion resistance
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Stainless Steel
Stainless steels are corrosion-resistant iron alloys that contain a minimum
of 10.5% chromium (Cr).
Other present alloying elements:
carbon (C), nickel (Ni), manganese (Mn), molybdenum (Mo), copper (Cu),
silicon (Si), sulphur (S), phosphorus (P) and nitrogen (N).
corrosion resistance
> 20µm thick ~ 2nm thick
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Passive layer
The natural formation of a passive surface film
is the key to the corrosion resistance of
stainless steels.
Properties of the passive film:
§  Chromium Rich Oxide (Oxy-hydroxides of
Fe and Cr)
§  Very thin, ~ 20-30 Ångströms (2-3 nm)
§  Extremely adherent
§  Passive
§  Self Repairing (within minutes)
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Damage to protective layer
Mild Steel
Stainless Steel

Passive film
Multi-layer Coating
Corrosion Products
Self Repair
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Effect of Chromium Content on Atmospheric
Corrosion Resistance
Corrosion Rate
mmpy
0.200
Plain Carbon Steel
0.175
0.150
0.125
0.100
0.075
Stainless Steels
0.050
> 10.5 Cr %
0.025
0 2 4 6 8 10 12 14 16
% Chromium
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Section 2
Chemical composition
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Chemical compositions for typical grades
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