CORROSION-RESISTANT STEEL FOR SULFUR-RICH OR HIGH TEMPERATURE ATMOSPHERES
COR-TEN® is a licensed brand and a part of the family of SSAB Weathering steel.
SSAB Weathering and COR-TEN® steels are frequently used in the petrochemical industry for industrial heat exchangers and in chimneys. These hard-wearing steels are resistant to sulfur-rich high temperature atmospheres, i.e. conditions that are damaging to other steel types.
A sulfur rich atmosphere occurs whenever oil, coal or other organic materials are burned.
Loves hot temperatures and corrosive environments
Unlike conventional carbon steel, SSAB Weathering steels are ideal for hot, corrosive environments. The stark difference in performance becomes clear when the steel types are compared under the extreme application conditions found in sulfur-rich atmospheres:
- At temperatures between 540°C to 650°C, COR-TEN® A offers a far greater resistance to scaling than carbon steel.
- In load bearing structures, the maximum recommended temperature for COR-TEN® B is 425°C.
- When excessive stresses are directed at a structure, the maximum recommended temperature for COR-TEN® A is 450°C.
Rust – the perfect protection
SSAB Weathering steels are extremely high strength. They are protected by a patina layer of rust that is formed in the oxidation process – a process that is vastly speeded up in corrosive, sulfur -rich environments. Thanks to this, unpainted weathering steels (often referred to as atmospheric corrosion resistant steel) require minimum maintenance.
In fact, virtually all chimneys made from SSAB Weathering steels and used in sulfur-rich environments, are still standing and in use.
Corrosion resistant steel
Corrosion behavior compared to normal carbon steel
Patina layer on the steel surface of weathering steels is adherent and resists cyclical corrosion loss. During first years of the patination process the corrosion speed is close to that of normal carbon steel.
Outdoor exposure in Finland after first 10 years
Patina formation is dependent on the atmospheric conditions. In rural areas, both COR-TEN A and COR-TEN B provide notable decrease in corrosion rate as compared to ordinary carbon steel S355. In industrial areas, COR-TEN A provides best resistance against corrosion due to the phosphorus alloying.
Paint once, twice the effect
Although there is no need to paint SSAB Weathering and COR-TEN® steels, it’s not uncommon to do so, particularly on very high chimneys that can be seen for many miles. When painted, the properties of the steel provide a very adhesive surface while ensuring there is no porous expanding of rust – something that can be a problem with carbon steel.
The steel also renowned for its “self-healing effect”, which minimizes corrosions creepage under a painted surface.
As a result, the interval between paint coatings is twice that of carbon steel. This also means that the appearance of painted SSAB Weathering and COR-TEN® steels remains neater for longer, in comparison to other painted steels.
Weathering steels in sulfur rich environments
SSAB Weathering and COR-TEN® steels extend the lifetime of many applications that are continuously subjected to high temperature, sulfur-rich environments. Baskets and plates in heat exchanger units, air preheaters and gas-gas heaters, are typical examples of products that are well suited for these steels.
At temperatures between 100–160°C, SSAB Weathering steels withstand flue gas conditions better than carbon steel if the surface is occasionally wet. At around 110°C, SSAB they even perform better than stainless steel.
High strength structural steel
SSAB Weathering and COR-TEN® steels are ideal for strong and light structures that last. They have a yield strength from 500 - 960 MPa and a tensile strength up to 580 - 1000 MPa. Hot rolled strips deliver the strongest weathering steel properties.
Some things to consider with SSAB Weathering and COR-TEN® steels
As with all critical materials and components there are recommendations for application use of SSAB Weathering and COR-TEN® steels. You can read more about them here.
Weather-resistant steel delivered as you like it
SSAB Weathering and COR-TEN® steel grades are delivered from stock locations or directly from the mill. Smaller quantities for testing are also available.
Download recommendations for application use of SSAB Weathering and COR-TEN® steels
Get in touch
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