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Stainless Steel 446 - 1.4749

This data sheet applies to stainless steel 446 / 1.4749 hot and cold rolled sheet and strip, semi-finished products, bars, rods and sections as well as for seamless steel tubes mechanical and general engineering purposes.


For construction parts, which should be resistant to scaling up to about 1100°C and extensively inured to the effects of sulphurous gases. The inclination to carbonisation in reduced gases is very low.

Chemical Compositions*

Element % Present (in product form)
Carbon (C) 0.15 - 0.20
Silicon (Si) 1.00
Manganese (Mn) 1.00
Phosphorous (P) 0.040
Sulfur (S) 0.015
Chromium (Cr) 26.00 - 29.00
Aluminium (Al) 0.15 - 0.25
Iron (Fe) Balance
*Maximum values unless otherwise stated

Mechanical properties (at room temperature in annealed condition)

Product Form
C, H, P L TS*
Thickness a or diamter d (mm) a ≤ 12 d ≤ 25 a = 12
Hardness HB max. 1) 2) 3) 212
Proof Strength3) Rp0.2 N/mm2 -
Rp1.0 N/mm2 280
Tensile Strength Rm N/mm2 500 - 700 500 - 700 min. 500
Elongation min. in % Long Products3) 15
Flat Products 0.5 ≤ a/d < 3 134)5) -
3 ≤ a/d 154)5) -
1) The maximum HB values may be raised by 100 units or the maximum tensile strength value may be raised by 200 N/mm2 and the minimum elongation value be lowered to 20% for cold worked sections and bars of ≤ 35mm thickness.
2) For guidance only
3) For rod, only the tensile values apply.
4) Longitudinal test piece.
5) Transverse test piece
* according to DIN EN 10297-2:2007-06

Creep Properties (estimated average values about the long-term behaviour at elevated temperature*)

1% Elongation1) for Rupture2) for
Temperature °C 1,000 h N/mm2 10,000 h N/mm2 1,000 h N/mm2 10,000 h N/mm2 100,000 h N/mm2
500 80 50 160 100 55
600 27.5 17.5 55 35 20
700 8.5 4.7 17 9.5 5
800 3.7 2.1 7.5 4.3 2.3
900 1.8 1.0 3.6 1.9 1.0
1) Stress related to the output cross section, which leads after 1,000 or 10,000 h to a permanent elongation of 1%.
2) Stress related to the output cross section, which leads after 1,000 or 10,000 or 100,000 h to breakage.
* For guidance only

Reference data on some physical properties

Density at 20°C kg/m3 7.7
Thermal Conductivity W/m K at 20°C 17
500°C 23
Specific Thermal Capacity at 20°C J/kg K 500
Electrical Resistivity at 20°C Ω mm2 /m 0.70

Coefficient of linear thermal expansion 10-6 K-1 between 20°C and

200°C 10.0
400°C 11.0
600°C 11.5
800°C 12.0
1000°C 13.0

Processing / Welding

Standard welding processes for this steel grade are:

  • TIG-Welding
  • MAG-Welding Solid Wire
  • Arc Welding (E)
  • Submerged Arc Welding (SAW)

Ferritic chrome steels are heat sensitive. Therefore the steel 1.4749 should be welded with lowest possible heat input by using thin electrode diameter, low current intensity and stringer bead welding. For wall thicknesses under 3mm, it is not necessary to preheat 1.4749. For thicker construction parts (> 3mm) the preheating and interpass temperatures 200 - 300°C should not be under respectively over run. 1.4749 can be processed with similar or higher alloyed filler metals. With sulphurous atmospheres a ferritic top layer should be laid on the media side (Thermanit L 1.4820).

Cold Forming

When cold forming 1.4749, certain preventative measures should be observed. Sheets up to 3mm thickness can be cold bent if necessary preheating with 200 - 300°C should be done. Products with thicknesses > 3mm must be preheated up to 600 - 800°C, concerning machinability 1.4749 can be compared to a low carbon steel.


While heating 1.4749 over about 950°C embrittlement by grain growth occurs, which cant be removed anymore. A further embrittlement occurs in the temperature range between 400 and 550°C (475°C embrittlement). A longer abidance within this temperature range should be avoided. This loss of ductility can be corrected by a short heating up to 700 to 800°C. In the temperature range of 600 to 900°C 1.4749 has the affinity to signma-phase-embrittlement, so that after longer application within this temperature range the ductile values are strongly reduced. The steel should not come into operation within this temperature range, if mechanical stress is existent.


The material is magnetizable.
Heat resisting tubes are delivered regarding testing in accordance to DIN EN 10297-2.
In Germany, SEW 470 still applies for heat resisting tubes.


thyssenkrupp Materials (UK) Ltd
Cox’s Lane
Cradley Heath
West Midlands
B64 5QU

Important Note

Information given in this data sheet about the condition or usability of materials respectively products are no warranty for their properties, but act as a description. The information, we give on for advice, comply to the experiences of the manufacturer as well as our own. We cannot give warranty for the results of processing and application of the products.

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