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EN 1.8509 (41CrAlMo7-10) Nitriding Steel

EN 1.8509 steel is an alloy steel formulated for primary forming into wrought products. Cited properties are appropriate for the quenched and tempered condition. 1.8509 is the EN numeric designation for this material. 41CrAlMo7-10 is the EN chemical designation.

It has a fairly low thermal conductivity among EN wrought alloy steels. In addition, it has a moderately low melting temperature and a very high tensile strength.

The graph bars on the material properties cards below compare EN 1.8509 steel to: EN wrought alloy steels (top), all iron alloys (middle), and the entire database (bottom). A full bar means this is the highest value in the relevant set. A half-full bar means it's 50% of the highest, and so on.

Mechanical Properties

Brinell Hardness

340

Elastic (Young's, Tensile) Modulus

190 GPa 27 x 106 psi

Elongation at Break

11 %

Fatigue Strength

580 MPa 84 x 103 psi

Impact Strength: V-Notched Charpy

29 J 21 ft-lb

Poisson's Ratio

0.29

Shear Modulus

73 GPa 11 x 106 psi

Shear Strength

680 MPa 98 x 103 psi

Tensile Strength: Ultimate (UTS)

1130 MPa 160 x 103 psi

Tensile Strength: Yield (Proof)

940 MPa 140 x 103 psi

Thermal Properties

Latent Heat of Fusion

250 J/g

Maximum Temperature: Mechanical

440 °C 820 °F

Melting Completion (Liquidus)

1450 °C 2640 °F

Melting Onset (Solidus)

1410 °C 2570 °F

Specific Heat Capacity

480 J/kg-K 0.11 BTU/lb-°F

Thermal Conductivity

39 W/m-K 22 BTU/h-ft-°F

Thermal Expansion

13 µm/m-K

Electrical Properties

Electrical Conductivity: Equal Volume

7.5 % IACS

Electrical Conductivity: Equal Weight (Specific)

8.6 % IACS

Otherwise Unclassified Properties

Base Metal Price

2.8 % relative

Density

7.8 g/cm3 490 lb/ft3

Embodied Carbon

1.6 kg CO2/kg material

Embodied Energy

22 MJ/kg 9.3 x 103 BTU/lb

Embodied Water

65 L/kg 7.7 gal/lb

Common Calculations

PREN (Pitting Resistance)

2.6

Resilience: Ultimate (Unit Rupture Work)

120 MJ/m3

Resilience: Unit (Modulus of Resilience)

2340 kJ/m3

Stiffness to Weight: Axial

13 points

Stiffness to Weight: Bending

25 points

Strength to Weight: Axial

40 points

Strength to Weight: Bending

31 points

Thermal Diffusivity

10 mm2/s

Thermal Shock Resistance

33 points

Alloy Composition

Among alloy steels, the composition of EN 1.8509 steel is notable for including aluminum (Al). Aluminum is used to control grain size and to deoxidize. Deoxidizing is required to control the effects of some other alloying elements.

Iron (Fe) 95.5 to 97.1
Chromium (Cr) 1.5 to 1.8
Aluminum (Al) 0.8 to 1.2
Manganese (Mn) 0.4 to 0.7
Carbon (C) 0.38 to 0.45
Molybdenum (Mo) 0.2 to 0.35
Silicon (Si) 0 to 0.4
Sulfur (S) 0 to 0.035
Phosphorus (P) 0 to 0.025

All values are % weight. Ranges represent what is permitted under applicable standards.

Followup Questions

Similar Alloys

Further Reading

ISO 683-5: Heat treatable steels, alloy steels and free-cutting steels - Part 5: Nitriding steels

Manufacture and Uses of Alloy Steels, Henry D. Hibbard, 2005

Ferrous Materials: Steel and Cast Iron, Hans Berns and Werner Theisen, 2008

Steels: Processing, Structure, and Performance, 2nd ed., George Krauss, 2015