Weather resistant structural steels
These weather-resistant structural steel grades are used for manufacturing welded, riveted or bolted structures, e. g. in bridge, façade and vehicle construction. In general, the specific rust-building properties of Allwesta steel grades make surface protections of structures built of this steel grade unnecessary, provided that the 'Stahl-Eisen-Werkstoffblatt' (Iron and steel material sheet) 087 Wetterfeste Baustähle, Richtlinien für die Lieferung, Verarbeitung und Anwendung’ (weather-resistant structural steel, guidelines for delivery, processing and application) is observed.
The user of these steel grades must make sure that his calculation, design and processing methods are appropriate for the material and comply with the state-of-the-art. The good properties of Allwesta steel grades are not negatively affected by cold or hot-forming. The minimum bending radii according to table 6 of DIN EN 10025-5 are recommended for cold-forming. Suitability for cold-forming must be agreed upon in the order.
If mechanical properties have been significantly modified by heavy cold-forming, either stress relief annealing or normalized may be applied. Normalized should also be applied following hot-forming outside of the temperature range of 750 - 1.050 °C and after overheating.
|Europe||Material no.||DE||FR||GB||US||JP||Salzgitter Flachstahl||FK1)|
|EN 10025-5||SEW 087||NFA 35-502||BS 4360||ASTM||JIS G 3114|
|S235J0W||1.8958||-||E 24 W 3||-||-||-||Allwesta 360||A|
|S235J2W||1.8961||WTSt 37-3||E 24 W 4||-||-||-||Allwesta 360 F||A|
|S355J0WP||1.8945||-||E 36 WA 3||WR 50 A||-||-||Allwesta 510 P||B|
|S355J2WP||1.8946||-||E 36 WA 4||-||A 242 Type 1||-||Allwesta 510 FP||B|
|S355J0W||1.8959||-||E 36 WB 3||WR 50 B||A 588||SMA 50 AW||Allwesta 510||B|
|S355J2W||1.8965||WTSt 52-3||E 36 WB 4||WR 50 C||-||SMA 50 CP||Allwesta 510 F||B|
|S355K2W||1.8967||-||-||-||-||-||Allwesta 510 F 40||B|
|S235J0W1)||0.13||0.40||0,20 - 0,60||max. 0,035||0.035||0,0092) 3)||0,40 - 0,80|
|S235J2W1)||0.13||0.40||0,20 - 0,60||max. 0,035||0.030||– 4)||0,40 - 0,80|
|S355J0WP1)||0.12||0.75||max. 1,0||0,06 - 0,15||0.035||0,0093)||0,30 - 1,25|
|S355J2WP1)||0.12||0.75||max. 1,0||0,06 - 0,15||0.030||– 4)||0,30 - 1,25|
|S355J0W1)5)||0.16||0.50||0,50 - 1,50||max. 0,035||0.035||0,0092) 3)||0,40 - 0,80|
|S355J2W1)5)||0.16||0.50||0,50 - 1,50||max. 0,030||0.030||– 4)||0,40 - 0,80|
|S355K2W1)5)||0.16||0.50||0,50 - 1,50||max. 0,030||0.030||– 4)||0,40 - 0,80|
|Grade||Position of sample||Min. yield strength2)||Tensile strength2)||Min. total elongation2)|
|L0 = 80 mm||L0 = 5,65 √S0|
|e ≤ 16||e > 16||e<3||e ≥ 3||e≤2||2< e < 2,5||2,5 < e < 3||e ≥ 3|
|S235J0W||l/t||235||225||360 - 510||360 - 510||19/17||20/18||21/19||26/24|
|S235J2W||l/t||235||225||360 - 510||360 - 510||19/17||20/18||21/19||26/24|
|S355J0WP||l/t||3553)||-||510 - 680||4703) - 6303)||16/14||17/15||18/16||22/203)|
|S355J2WP||l/t||3553)||-||510 - 680||4703) - 6303)||16/14||17/15||18/16||22/203)|
|S355J0W||l/t||355||345||510 - 680||470 - 630||16/14||17/15||18/16||22/20|
|S355J2W||l/t||355||345||510 - 680||470 - 630||16/14||17/15||18/16||22/20|
|S355K2W||l/t||355||345||510 - 680||470 - 630||16/14||17/15||18/16||22/20|
|Grade||Temperature [°C]||Notch impact energy1) [J]|
Unlike unalloyed constructional steels, when copper is added as an alloy in weather-resistant steels, a barrier layer forms when the steel comes into contact with the atmosphere. This layer contains alkaline copper sulfate (see diagram).
In the case of the phosphorous-alloyed steel grades Allwesta 510 P and Allwesta 510 FP (S355J0WP and S355J2WP), the barrier layer is also strengthened by alkaline copper phosphate.
Depending on the environmental conditions, the formation of this barrier layer takes approx. 1,5 - 3,5 years and prevents water, oxygen and sulfur dioxide from coming into contact with the surface of the steel. There is then no further corrosion.
The prerequisites for the formation of the protective coating are as follows:
- No permanent moisture
- Uniform run-off of rainwater
- Avoidance of small cracks (capillary formation)
- Protective coating to protect against condensation water on the inside
- Absence of chlorides (seawater, near to the coast)
- Permanent fluctuation between moisture and dryness
- Avoidance of electrochemical local elements
As the protective coating forms, the color changes from light brown to brown to brown-violet; the surface becomes dark brown / violet and grainy. The color changes, depending on the incidence of light and the weather conditions.
Salzgitter Flachstahl should like to point out that, during the formation of the protective coating, specks may form as a result of the washout of rust; this should be taken into account in the design.
The steel grades of the Allwesta series can be perfectly welded both manually and using automatic equipment by means of all known welding processes. However, the quality of the weld joint depends on the welding process, the welding conditions and the selection of the correct filler metals. Suitably alloyed filler metals shall be used if the same requirements regarding weather resistance are made on the basic material and the weld metal and if the structure is not to be provided with a painting coat.
In general, pre-heating prior to welding or torch-cutting is not necessary. Only when external temperatures drop below -5 °C should the metal be pre-heated to approx. 150 °C.
Condition of delivery, scope of testing and certificate
Flat products made of Allwesta steel grades have the condition of delivery +N (normalized rolled). The provisions of EN 10025-5 shall apply for delivery and inspection.
Certificates according to DIN EN 10025-5 can be supplied as follows: IT, DUN, FAX, e-mail, paper.