Fermonic 50 – High Strength / Extra High Strength (UNS S20910 XM-19)


Fermonic® 50 – HS/EHS is a nitrogen-strengthened austenitic stainless steel that can be supplied in the cold worked or warm worked condition (it is also known as Nitronic® 50 – a trademark owned by AK Steel Corporation). Although very small diameter bars of Fermonic® 50 (<2.25”) can be cold worked to achieve higher strength levels, larger section sizes can only achieve dramatically increased mechanical properties by deforming at raised temperatures. This results in a deformed and partly recrystallised micro structure that is ‘stress free’, achieves high strengths with good ductility and consistent properties through the bar (unlike cold worked material). The superior properties of Fermonic® 50 HS/EHS are available up to 9” diameter bars.

This product maintains excellent ductility and toughness at both elevated and cryogenic temperatures, combined with improved abrasion and erosion resistance relative to other austenitic stainless steel grades, making it a useful and cost-effective alloy in a wide range of demanding applications. It can generally be formed and welded in the same way as other 3xx alloys, although machining may require slower speeds / more power due to its high work hardening rate. It achieves corrosion resistance equivalent or better than Alloy 317L in a wide range of environments, and is listed in NACE MR 01 75 for sour service given its ability to resist sulphide stress cracking.

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Product Features:

Key Features:

  • Higher strength and hardness than other austenitic stainless steels such as Alloy 304, Alloy 316L & Alloy 317L
  • Excellent ductility and toughness at both elevated and cryogenic temperatures
  • Non-magnetic, even after severe cold working, making it suitable for sensor applications
  • Excellent corrosion resistance, including resistance to chloride and sulphide stress cracking
  • Higher resistance to abrasion, erosion and cavitation erosion than Alloy 304, Alloy 316L & Alloy 317L austenitic stainless steels
  • Listed in food handling standards (FDA) as an acceptable material for food contact surfaces
  • Listed in MR 0175 for sour service oilfield applications


  • Oil & Gas industry downhole equipment
  • Marine pumps, valves, masts, tie downs, fixtures and fittings
  • Food processing equipment
  • Process industry equipment in sulphuric acid, nitric acid, polythionic acid, urea production, organic & fatty acids
  • Pulp and paper Industry valves and fittings

Chemical Composition:

Cr Ni Mo Co Nb (+Ta) Ti V W Cu C Mn N Si P S Fe Al
Min 20.50 11.50 1.50 0.10 0.10 4.00 0.20
Max 23.50 13.50 3.00 0.30 0.30 0.06 6.00 0.40 1.00 0.045 0.030 Bal

Mechanical Properties:

Fermonic® 50 - High Strength (cold worked condition, up to 1.5” /38mm diameter or section) Fermonic® 50 - High Strength (cold worked condition, bars between 1.5”-2.25” /38mm – 57mm diameter or section) Fermonic® 50 - High Strength (warm worked condition) Fermonic® 50 – Extra High Strength
0.2% Proof Stress 862 N/mm2 125 ksi 725 N/mm2 105 ksi 725 N/mm2 105 ksi 827 N/mm2 120 ksi
Tensile Strength 1000 N/mm2 145 ksi 827 N/mm2 125 ksi 896 N/mm2 125 ksi 930 N/mm2 135 ksi
Elongation, 5.65√S0 and 4D 12% 15% 20% 20%
Reduction of Area 40% 45% 50% 40%
Hardness 328 HBN max. 328 HBN max. 25-35HRC 25-35HRC
Impact Strength (Room Temp) 135J 135J
Impact Strength (-60oC) 40J 40J


  1. Testing shall be carried out in accordance with ASTM A370 or EN ISO 6892-1 (tensile), EN ISO 6506-1 (hardness)
  2. Minimum properties quoted (tested at room temperature in a longitudinal direction)
  3. Testing performed on each melt of material per heat treatment batch

Physical Properties:

Density (Kg/m3) 7880
Magnetic Permeability (20°C) <1.02
Young’s Modulus (kN/mm2) 197
Specific Electrical Resistance, 20°C (µΩ-m) 0.82
Mean coefficient of thermal expansion, 20-100°C (m/m/°C) 17.9 x 10-6
Specific Heat, 20°C (J/kg.K) 475
Thermal conductivity, 20°C (W/m.K) 13.3
Fracture Toughness, KQ (MPa/m2)


Datasheet - S-Fermonic 50 HS&EHS

Datasheet - S-Fermonic 50 HS&EHS

Brochure - Fermonic 50 - Detailed product information (rev2)

Brochure - Fermonic 50 - Detailed product information (rev2)