Therma

Stainless steels for high service temperatures

Browse Therma range specifications Visit Stainless Steel Finder

Therma range contains heat-resistant stainless steels for use in applications with high service temperatures. This product has excellent oxidation and creep resistance. 

Value to our customers

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Benefits

Why Therma range

  • Ferritics are resistant to sulfur-containing hot gases and have lower thermal expansion than austenitics.
  • Austenitics are resistant to carburizing and nitriding/low-oxygen hot gases. They also have higher creep strength than ferritics.
  • Due to their higher creep strength and oxidation resistance, Therma MA (micro-alloyed) stainless steels give you a longer product lifecycle.

Attributes

  • Therma 253 MA is an austenitic stainless steel with excellent oxidation and creep resistance in cyclic conditions that is best employed in temperatures up to 1150°C/2100°F.
  • Therma 310S/4845 is an austenitic product with very good oxidation resistance in general and good oxidation resistance in mildly cyclic conditions that are best employed in temperatures up to 1050°C/1920°F.
  • Therma range contains stainless steel for use in applications with high service temperatures (≥550°C/1020°F).

Therma range

Our Therma range is especially suitable for applications with high service temperatures. Ferritic stainless steels have resistance to sulfur-containing hot gases and lower thermal expansion. Austenitic stainless steels have resistance to carburizing and nitriding/low oxygen hot gas and higher creep strength.

The Therma 253 MA offers an austenitic stainless steel with excellent oxidation and creep resistance in cyclic conditions that is best employed in high temperatures. Therma 310S/4845 presents an austenitic product with excellent oxidation resistance in mildly cyclic conditions.

Grades

Therma 253 MA

An austenitic 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 between 600–850°C/1110–1560°F.

EN 1.4835

ASTM type -

ASTM UNS S30815

Microstructure Austenitic

Typical applications

  • Oil industry equipment
  • Conveyor belts
  • Refractory anchors
  • Expansion bellows
  • Radiant tubes
  • Rotary kilns
  • Exhaust manifolds
  • Power generation applications
  • Cyclone dip tubes
  • Impact separators
  • Bell furnaces
  • Muffle furnaces
  • Automotive exhaust components
  • Tube shields
  • Heat treatment trays
  • Dampers
  • Recuperator tubes
  • Large-scale bakery ovens
  • Valves and flanges

Datasheet

Download Therma range datasheet for more information on corrosion resistance, mechnanical properties, physical properties and fabrication

Typical chemical composition, % by mass

C 0.09

Cr 21.0

Ni 11.0

Mo -

N 0.17

Others Si, Ce

Therma 310S/4845

An austenitic product with very good oxidation resistance in general and good oxidation resistance in mildly cyclic conditions that is best employed in temperatures up to 1050°C/1920°F. There is a slight susceptibility to embrittlement during continuous operation between 600–900°C/1110–1652°F

EN 1.4845

ASTM type 310S

ASTM UNS S31800

Microstructure Austenitic

Typical applications

  • Furnace equipment
  • Oil industry equipment
  • Heat treatment baskets
  • Heat exchangers
  • Steam boilers
  • Thermowells
  • Automotive components
  • Valves and flanges

Typical chemical composition, % by mass

C 0.05

Cr 25.5

Ni 19.1

Mo -

N -

Others -

Therma 4713

A ferritic low-alloyed stainless steel best employed at 550–800°C/1020– 1470°F when you need higher mechanical loading compared to other ferritic grades. Offers good resistance against sulfur attack compared to nickel-alloyed grades. 

EN 1.4713

ASTM type -

ASTM UNS -

Microstructure Ferritic

Typical applications

  • Furnace equipment
  • Air heaters
  • Annealing boxes
  • Conveyor belts
  • Thermowells

Datasheet

Download Therma range datasheet for more information on corrosion resistance, mechnanical properties, physical properties and fabrication

Typical chemical composition, % by mass

C 0.06

Cr 6.5

Ni -

Mo -

N -

Others Al, Si 

Therma 4724

A ferritic low-alloyed product with improved oxidation resistance in temperatures up to 850°C/1560°F.

EN 1.4724

ASTM type -

ASTM UNS -

Microstructure Ferritic

Typical applications

  • Furnace equipment
  • Thermal boiler components
  • Grids
  • Burner nozzles
  • Conveyor belts
  • Thermowells

Datasheet

Download Therma range datasheet for more information on corrosion resistance, mechnanical properties, physical properties and fabrication

Typical chemical composition, % by mass

C 0.07

Cr 12.5

Ni -

Mo -

N -

Others Al, Si

Therma 4742

A ferritic stainless steel with very good oxidation resistance in temperatures up to 1000°C/1830°F, but which begins to be subject to embrittlement at temperatures above 950°C/1740°F.

EN 1.4742

ASTM type -

ASTM UNS -

Microstructure Ferritic

Usage

  • Grids
  • Burner nozzles
  • Conveyor belts
  • Chains
  • Machine parts
  • Cement processing equipment

Datasheet

Download Therma range datasheet for more information on corrosion resistance, mechnanical properties, physical properties and fabrication

Typical chemical composition, % by mass

C 0.07

Cr 17.5

Ni -

Mo -

N -

Others Al, Si 

Therma 304H/4948

An austenitic Core 304/4301 variant with improved high-temperature creep strength that is best employed in temperatures up to 750°C/1380°F. Offers good formability and weldability.

EN 1.4948

ASTM type 304H

ASTM UNS S30409

Microstructure Austenitic

Typical applications

  • Tubes
  • Pressure vessels
  • Valves and flanges

Datasheet

Download Therma range datasheet for more information on corrosion resistance, mechnanical properties, physical properties and fabrication

Typical chemical composition, % by mass

C 0.05

Cr 18.1

Ni 8.3

Mo -

N -

Others -

Therma 321H/4878

An austenitic heat resisting stainless steel with comparable wet corrosion resistance to Core 321/4541 that is best employed in temperatures up to 850°C/1560°F

EN 1.4878

ASTM type 321H

ASTM UNS -

Microstructure Austenitic

Typical applications

  • Furnace equipment
  • Case hardening boxes
  • Valves and flanges

Datasheet

Download Therma range datasheet for more information on corrosion resistance, mechnanical properties, physical properties and fabrication

Typical chemical composition, % by mass

C 0.05

Cr 17.3

Ni 9.1

Mo -

N -

Others Ti 

Therma 347H

An austenitic heat resisting stainless steel with excellent long-term creep resistance at at 550–600°C/1020–1110°F and comparable wet corrosion resistance to Core 347/4550.

EN -

ASTM type 347H

ASTM UNS S34709

Microstructure Austenitic

Usage

  • Oil refineries
  • Fired heater tubes
  • Boiler casings
  • Pressure vessels
  • Reactor vessels
  • Welded tubes
  • Fittings
  • Stack liners
  • Tanks for storing organic chemicals
  • Furnace heating elements
  • Tanks for thermal storage
  • Valves and flanges

Datasheet

Download Therma range datasheet for more information on corrosion resistance, mechanical properties, physical properties and fabrication.

Typical chemical composition, % by mass

C 0.05

Cr 17.5

Ni 9.5

Mo -

N -

Others Nb

Therma 4828

An austenitic heat resisting stainless steel with improved oxidation resistance in temperatures up to 1000°C/1830°F. There is a slight susceptibility to embrittlement during continuous operation atbetween 600–850°C/1110– 1560°F.

EN 1.4828

ASTM type -

ASTM UNS -

Microstructure Austenitic

Typical applcations

  • Furnace equipment (especially supporting parts)
  • Annealing and hardening boxes
  • Air heaters
  • Exhaust systems
  • Automotive components such as turbochargers
  • Valves and flanges

Datasheet

Download Therma range datasheet for more information on corrosion resistance, mechanical properties, physical properties and fabrication.

Typical chemical composition, % by mass

C 0.05

Cr 19.3

Ni 11.2

Mo -

N -

Others Si

Therma 309S/4833

An austenitic stainless steel with improved oxidation resistance in temperatures up to 1000°C/1830°F. There is a slight susceptibility to embrittlement during continuous operation at 600–900°C/1110–1652°F.

EN 1.4833

ASTM type 309S

ASTM UNS S30908

Microstructure Austenitic

Usage

  • Furnace equipment
  • Annealing boxes
  • Thermowells
  • Baffle plates
  • Pots for quenching salt
  • Valves and flanges

Datasheet

Download Therma range datasheet for more information on corrosion resistance, mechanical properties, physical properties and fabrication.

Typical chemical composition, % by mass

C 0.06

Cr 22.3

Ni 12.3

Mo -

N -

Others -

Therma 153 MA

An austenitic stainless steel with excellent oxidation and creep resistance in cyclic conditions that is best employed in temperatures up to 1050°C/1920°F. This product has an excellent resistance to embrittlement.

EN 1.4818

ASTM type -

ASTM UNS S30415

Microstructure Austenitic

Typical applications

  • Recuperators
  • Conveyor belts
  • Expansion bellows
  • Power generation applications
  • Cyclone dip tubes
  • Bell furnaces
  • Muffle furnaces
  • Automotive components
  • Tube shields
  • Heat treatment trays
  • Dampers
  • Valves and flanges

Datasheet

Download Therma range datasheet for more information on corrosion resistance, mechanical properties, physical properties and fabrication.

Typical chemical composition, % by mass

C 0.05

Cr 18.5

Ni 9.1

Mo -

N 0.15

Others Si,Ce

Therma 314/4841

An austenitic heat resisting stainless steel with excellent oxidation resistance in temperatures up to 1150°C/2100°F. There is a high susceptibility to embrittlement during continuous operation at 600–900°C/1110–1652°F

EN 1.4841

ASTM type 314

ASTM UNS S31400

Microstructure Austenitic

Typical applications

  • Furnace equipment
  • Superheater suspensions
  • Enameling grates and hardening boxes
  • Valves and flanges

Datasheet

Download Therma range datasheet for more information on corrosion resistance, mechanical properties, physical properties and fabrication.

Typical chemical composition, % by mass

C 0.06

Cr 24.3

Ni 19.2

Mo -

N -

Others Si

Go directly to Grades

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, see steelfinder.outokumpu.com

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