- Oil industry equipment
- Conveyor belts
- Refractory anchors
- Expansion bellows
- Radiant tubes, tube shields, and valves and flanges
- Rotary kilns
- Exhaust manifolds
- Power generation applications
- Cyclone dip tubes
- Impact separators
- Bell furnaces and muffle furnaces
- Automotive components
- Heat treatment trays
- Dampers
- Recuperator tubes for the steel industry
- Large-scale bakery ovens
Outokumpu Therma grades
Therma 253 MA®
Therma 253 MA is a stainless steel with excellent oxidation and creep resistance in cyclic conditions that is best employed in temperatures up to 1150 °C/2100 °F. There is a slight susceptibility to embrittlement during continuous operation at 600–850 °C/1110–1560 °F.
Therma 310S/4845
Austenitic heat resisting 4845 grade with very good oxidation resistance. This grade 4845 belongs to austenitic chromium-nickel stainless steel grades. A specific feature for 4845 grade is high chromium and high nickel contents, which make this grade suitable for use in high temperatures. A common feature of Outokumpu high temperature steels is that they are designed primarily for use at temperatures exceeding ~550 °C, i.e. in the temperature range where creep strength as a rule is the dimensioning factor and where HT corrosion occurs. Optimising steels for high temperatures has meant that their resistance to aqueous corrosion has been limited. All steels are austenitic, resulting in relatively high creep strength values.
Characteristic properties
• Good resistance to oxidation
• Good resistance to high-temperature corrosion
• Good mechanical strength at elevated temperatures
Outokumpu high temperature steels can be and have been used in a number of applications where the temperature exceeds 550°C, e.g. for equipment and components within:
- Industrial furnace equipment
- Oil industry equipment
- Heat treatment baskets
- Heat exchanges
- Steam boilers and thermowells
- Iron, steel, and non-ferrous industries
- Engineering industry
- Energy conversion plants
- Cement industry
Therma Alloy 800
The Therma range contains heat-resisting stainless steels and alloys for use in applications with high service temperatures normally > 550 °C/1020 °F. Outokumpu Therma Alloy 800 is a high temperature alloy design for high creep strength, resistance to carburization, oxidation, and other types of high-temperature corrosion.
Therma Alloy 800 (EN 1.4876, UNS N08800) is stabilized austenitic alloys with high Nickel and Chromium content as well as controlled additions of Carbon, Titanium and Aluminum. Additionally, grain size is controlled for improved creep strength properties.
- Heating element tubing
- General high-temperature service in carburizing conditions
- Steam/hydrocarbon reformers
- Heat exchangers
- High temperature process equipment
Therma Alloy 800/800H
The Therma range contains heat-resisting stainless steels and alloys for use in applications with high service temperatures normally > 550 °C/1020 °F. Outokumpu Therma Alloy 800/800H & 800T is a series of high temperature alloys design for high creep strength, resistance to carburization, oxidation, and other types of high-temperature corrosion.
Therma Alloy 800 series (EN 1.4876/1.4958/1.4959, UNS N08800/N08810/N08811) are stabilized austenitic alloys with high Nickel and Chromium content as well as controlled additions of Carbon, Titanium and Aluminum. Additionally, grain size is controlled for improved creep strength properties.
Heating element tubing
General high-temperature service in carburizing conditions
Steam/hydrocarbon reformers
Heat exchangers
High temperature process equipment
Therma Alloy 800T
The Therma range contains heat-resisting stainless steels and alloys for use in applications with high service temperatures normally > 550 °C/1020 °F. Outokumpu Therma Alloy 800/800H/800T is a series of high temperature alloys design for high creep strength, resistance to carburization, oxidation, and other types of high-temperature corrosion.
Therma Alloy 800 series (EN 1.4876/1.4958/1.4959, UNS N08800/N08810/N08811) are stabilized austenitic alloys with high Nickel and Chromium content as well as controlled additions of Carbon, Titanium and Aluminum. Additionally, grain size is controlled for improved creep strength properties.
Heating element tubing
General high-temperature service in carburizing conditions
Steam/hydrocarbon reformers
Heat exchangers
High temperature process equipment
Therma 4910
Austenitic creep resisting grade with good resistance to stress relaxation cracking. Therma 4910 belongs to the austenitic chromium-nickel-molybdenum stainless steel grades. A specific feature for Therma 4910 grade is high creep resistance as a result of nitrogen and boron alloying, which makes this grade suitable for use in high temperatures. The low carbon content is unusual in creep resisting steels and together with absence of strong carbide forming elements such as titanium and niobium, carbide precipitation leading to stress relaxation cracking is minimized.
A common feature of Outokumpu high temperature steels is that they are designed primarily for use at temperatures exceeding ~550 °C, i.e. in the temperature range where creep strength as a rule is the dimensioning factor and where HT corrosion occurs. Therma 4910 is intended for use up to about 800°C. Optimising steels for high temperatures has meant that their resistance to aqueous corrosion has been limited. All steels are austenitic, resulting in relatively high creep strength values.
Characteristic properties:
- Good resistance to oxidation, suitable for use up to about 800 °C
- Good resistance to high-temperature corrosion
- Excellent mechanical strength at elevated temperatures
- Resistance to stress relaxation cracking, useful especially in the heat affected zone of weldments
- Although not intended for wet corrosion applications, the presence of molybdenum and nitrogen is beneficial for pitting corrosion resistance in chloride environments
Outokumpu high temperature steels can be and have been used in a number of applications where the temperature exceeds 550°C, e.g. for equipment and components within:
- Industrial furnace equipment
- Oil industry equipment
- Heat treatment baskets
- Heat exchanges
- Steam boilers and thermowells
- Iron, steel, and non-ferrous industries
- Engineering industry
- Energy conversion plants
- Cement industry
- Thermal Energy Storage
- Molten nitrate salt handling
Therma 4713
Therma 4724
Low-alloyed ferritic heat resisting grade with improved scaling resistance. Uncritical regarding embrittlement at service temperatures. Applied for e.g. furnace equipment, thermal boiler components, grids, burner nozzles, conveying parts, thermowells.
The high temperature (HT) ferritic stainless steels complement Outokumpu austenitic heat and creep portfolio. The main alloying element in the ferritic grades is chromium. Its positive effect on the scaling resistance is enhanced by silicon and aluminium. The characteristic properties are excellent resistance to oxidising and reducing sulphur containing atmospheres, good resistance to oxidation and high thermal conductivity with low thermal expansion.
4713 does not form brittle phases but should only be exposed to moderately corrosive atmospheres owing to its low chromium content.
4724 is a truly stainless high temperature grade with 13% chromium. It is not critical in terms of embrittlement. 4742 shows better scaling resistance than 4724 and can be subjected to reducing sulphur environments without risk. It is subject to 475°C embrittlement and grain coarsening at temperatures above 950°C. σ-phase may form after long time exposures to temperatures around 650°C.
4762 - with the highest chromium content- is the most resistant to reducing sulphurous gases. It is susceptible to the same embrittlement phenomena as 4742 whilst σ-phase forms during long exposures in the range 600°C to 800°C.
Outokumpu Stainless ferritic high temperature steels are mostly used in high temperature applications with sulphurous atmospheres and/or low tensile loads such as for installations within:
- Furnace equipment
- Thermal boiler components
- Grids
- Burner nozzles
- Conveying parts
- Thermowells
- Chemical industry (drums)
- Power industry (coal burners)
- Metalworking industry (heat treatment boxes)
Therma 304H/4948
Stainless steel grade with wet corrosion resistance and improved high-temperature strength (creep resisting steel). Good formability and weldability. Commonly used for tubes and pressure vessels.
A common feature of Outokumpu high temperature steels is that they are designed primarily for use at temperatures exceeding ~550 °C, i.e. in the temperature range where creep strength as a rule is the dimensioning factor and where HT corrosion occurs. Optimising steels for high temperatures has meant that their resistance to aqueous corrosion has been limited. All steels are austenitic, resulting in relatively high creep strength values.
Outokumpu high temperature steels can be and have been used in a number of applications where the temperature exceeds 550°C, e.g. for equipment and components within:
- Tubes
- Pressure vessels
- Iron, steel, and non-ferrous industries
- Engineering industry
- Energy conversion plants
- Cement industry
Therma 321H/4878
Low alloyed grade. Commonly used for furnace equipment, case hardening boxes.
A common feature of Outokumpu high temperature steels is that they are designed primarily for use at temperatures exceeding ~550 °C, i.e. in the temperature range where creep strength as a rule is the dimensioning factor and where HT corrosion occurs. Optimising steels for high temperatures has meant that their resistance to aqueous corrosion has been limited. All steels are austenitic, resulting in relatively high creep strength values.
Outokumpu high temperature steels can be and have been used in a number of applications where the temperature exceeds 550°C, e.g. for equipment and components within:
- Furnace equipment
- Case hardening boxes
- Iron, steel, and non-ferrous industries
- Engineering industry
- Energy conversion plants
- Cement industry
Therma 309S/4833
Austenitic grade with improved oxidation resistance. Commonly used for furnace equipment, annealing boxes, thermo wells, baffle plates and salt pots.
A common feature of Outokumpu high temperature steels is that they are designed primarily for use at temperatures exceeding ~550 °C, i.e. in the temperature range where creep strength as a rule is the dimensioning factor and where HT corrosion occurs. Optimising steels for high temperatures has meant that their resistance to aqueous corrosion has been limited. All steels are austenitic, resulting in relatively high creep strength values.
Outokumpu high temperature steels can be and have been used in a number of applications where the temperature exceeds 550°C, e.g. for equipment and components within:
- Furnace equipment
- Annealing boxes
- Thermo wells
- Baffle plates and salt pots
- Iron, steel, and non-ferrous industries
- Engineering industry
- Energy conversion plants
- Cement industry
Therma 314/4841
Austenitic heat resisting grade with excellent oxidation resistance. Commonly used for furnace equipment, super heater suspensions, enameling grates etc.
A common feature of Outokumpu high temperature steels is that they are designed primarily for use at temperatures exceeding ~550 °C, i.e. in the temperature range where creep strength as a rule is the dimensioning factor and where HT corrosion occurs. Optimising steels for high temperatures has meant that their resistance to aqueous corrosion has been limited. All steels are austenitic, resulting in relatively high creep strength values.
Outokumpu high temperature steels can be and have been used in a number of applications where the temperature exceeds 550°C, e.g. for equipment and components within:
- Furnace equipment
- Super heater suspensions
- Enameling grates
- Iron, steel, and non-ferrous industries
- Engineering industry
- Energy conversion plants
- Cement industry
For High Service Temperatures
Therma
The Therma range contains heat- and creep-resisting stainless steels with excellent oxidation and creep resistance for use in applications with high service temperatures (≥ 550°C/1020°F).
Austenitic heat- and creep-resisting stainless steels have resistance to carburizing and nitriding/low oxygen hot gas and higher creep strength, in general.
Therma 253 MA/4835 (EN 1.4835) is an austenitic heat-resisting stainless steel with excellent oxidation and creep resistance in cyclic conditions and is best employed in high temperatures up to 1100°C/2012°F.
Therma 310S/4845 (EN 1.4951) is an austenitic heat- and creep-resisting stainless steel with excellent oxidation resistance in mildly cyclic conditions and is best employed in high temperatures up to 1050°C/1920°F.
The ferritic heat-resisting stainless steels Therma 4713 (EN 1.4713) and Therma 4724 (EN 1.4724) have good resistance to sulfur-containing hot gases and lower thermal expansion compared to nickel-alloyed grades. Therma 4713 and Therma 4724 are best employed in temperatures up to 800°C/1470°F and 850°C/1560°F, respectively
Standards and approvals
EN 10028-7 | Flat products for pressure purposes – Stainless steels |
EN 10088-1 | Stainless steels – Part 1: List of stainless steels |
EN 10088-2 | Stainless steels – Corrosion resisting sheet/plate/strip for general and construction purposes |
EN 10088-3 | Stainless steels – Corrosion resisting semi-finished products/bars/rods/wire/sections for general and construction purposes |
EN 10088-4 | Stainless steel flat products, technical delivery conditions, steels for constructions |
EN 10217-7 | Welded steel tubes for pressure purposes – Stainless steel tubes |
EN 10296-2 | Welded circular steel tubes for mechanical and general engineering purposes - Stainless Steel tubes |
ASTM A182 / ASME SA-182 | Forged or rolled alloy-steel pipe flanges, forged fittings etc. for high temperature service |
ASTM A240 / ASME SA-240 | Heat-resisting Cr and Cr-Ni stainless steel plate/sheet/strip for pressure purposes |
ASTM A276 | Stainless and heat-resisting steel bars/shapes |
ASTM A479 / ASME SA-479 | Stainless steel bars for boilers and other pressure vessels |
Eurocode 3 / EN 1993-1-4 | Design of steel structures – Part 1-4: General rules – Supplementary rules for stainless steels |
ISO 15510 | Stainless steels – chemical composition |
The most commonly used international product standards are given in the table. For a list of standards by product, visit Steel Finder.