SSAB Weathering 355ML
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General Product Description
SSAB Weathering 355ML steel grade is thermomechanically rolled structural steel offering a good weather resistance. This steel has excellent usability properties. Its surface quality, dimensional accuracy and the consistency of its properties are among the best on the market. Thanks to its good properties, these steels promote environmentally sound construction and sustainable development.
SSAB Weathering 355ML brings clear performance benefits for heavy steel structures like bridges. Thanks to the excellent resistance to atmospheric corrosion, there is no need for the additional coatings, such as painting of steel structures. Therefore, a significant cost advantage can be achieved in applications, where a dark brown patina is desired on the steel surface. However, the steel surface can be shot blasted and painted, using the same methods as when painting ordinary steel grades. As a result of the special alloying of the steel, the lifespan of the painting is about double that of an ordinary steel grade painted.
The anti-corrosion properties of SSAB Weathering 355ML are much better than those of the ordinary structural steels which are commonly used in many outdoor applications. The enhanced weather resistance is based on the oxide layer, i.e. patina. The elegantly brown patinated surface is architecturally distinguished. Patina starts to be yellowish first and when the time goes on the color will turn to darker brown.
SSAB Weathering 355ML meets or exceeds the requirements of S355J5W+M in EN 10025-5. Dual certification and CE marking are available upon request.
Dimension Range
SSAB Weathering 355ML is available in thickness 8.0 - 65.0 mm.
Mechanical Properties
The tensile test is made transverse to the rolling direction in compliance with EN 10025-1 and EN 10025-5.
Certificates:
SSAB Weathering 355ML provides two different certificates:
EN 10204-3.1 to SSAB Weathering 355ML and S355J5W+M.
Impact Properties
The impact test is made longitudinally to the rolling direction in compliance with EN 10025-1 and EN 10025-5.
Chemical Composition (heat analysis)
Carbon Equivalent
Tolerances
Thickness ¾ from EN 10029 Class A. Width and length according to EN 10029.
Flatness 6 mm/m.
Surface according to EN 10163-2 Class A subclass 3.
Delivery Conditions
Thermomechanically rolled (M).
Possible to order as shot blasted & primed.
Fabrication and Other Recommendations
The weldability of SSAB Weathering ML steel is excellent. Thermomechanically processed steels have good resistance to hydrogen cracking and reduced need for preheating. All conventional welding methods can be used. If the welded structure shall be made according to the standard EN 1090-2 rules, the selection of acceptable welding consumables shall follow the standard EN 1090-2.
SSAB Weathering 355 ML steels have a low CEV carbon equivalent. According to the method A of standard EN 1011-2, preheating is not required when the hydrogen content of the welding consumable is at most 10 ml/100 g. Selecting low hydrogen welding consumables minimizes the risk of hydrogen cracking and reduces the need for preheating. When welding is done with low hydrogen welding consumables (hydrogen content ≤ 5 ml/100 g), the risk of hydrogen cracking is very low.
According to the standard EN1011-2, slight preheating of +50°C is recommended when using low heat input Q < 1.0 kJ/mm and when the combined plate thickness is over 50 mm. This type of situation may arise, for instance regarding tack welds or the root pass of butt weld. When considering the need of preheating, it is also important to take into account the demanding conditions specified in standard EN 1011-2. The following factors should be considered:
- Residual stresses of the welded assembly is a complex factor influenced by the plate thickness, joint geometry, and the stiffness of the fabrication. When the stiffness of the joint and residual stresses in the joint increase, preheating is beneficial. for instance when the plate thickness exceed 40 mm and when welding for example a root pass in a X-groove preparation, it is helpful to use light preheat +50…100°C because of the high stresses and small heat input.
- The instructions given for steel plates may not be sufficient to prevent hydrogen cracking in the weld metal when welding steels with a low CEV carbon equivalent. The preheating requirement of the welding consumable should be considered separately.
- When welding steels with different carbon equivalent values, the preheating requirement should be determined based on the more demanding steel and higher CEV value.
- The most effective way to prevent hydrogen cracking in thick plates is to reduce the hydrogen content in the weld metal and prefer welding consumables with a hydrogen content of at most 5 ml/100g. Additionally, welding should be done in dry and clean grooves.
Forming up to 20 mm:
Minimum inner bending radius 2 x t can be used in both longitudinal and transverse direction in 90 degree three-point bending. Minimum die-width is recommended to be at least 10 x t. Close attention should be paid on the cut edges in the bend area and all excessive cracks or burrs should be removed. It is also important to be sure that the plate surface is defect free (no scratches) on the deformation area before bending.
Surface:
In order to achieve even good looking patina layer scale removal is recommended. That can be done either with pickling or shot blasting.
For information concerning fabrication, see SSAB´s brochures on www.ssab.com or consult Tech Support.
Appropriate health and safety precautions must be taken when bending, welding, cutting, grinding or otherwise working on the products.
Contact Information
www.ssab.com/contact