UNS S44627 (XM-27) Stainless Steel
S44627 stainless steel is a ferritic stainless steel formulated for primary forming into wrought products. Cited properties are appropriate for the annealed condition. XM-27 is the ASTM designation for this material. S44627 is the UNS number.
It has a moderately low thermal conductivity among wrought ferritic stainless steels. In addition, it has a moderately low electrical conductivity and a moderately high base cost.
The graph bars on the material properties cards below compare S44627 stainless steel to: wrought ferritic stainless 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
170
Elastic (Young's, Tensile) Modulus
200 GPa 29 x 106 psi
Elongation at Break
24 %
Fatigue Strength
200 MPa 29 x 103 psi
Poisson's Ratio
0.27
Reduction in Area
51 %
Rockwell B Hardness
79
Shear Modulus
80 GPa 12 x 106 psi
Shear Strength
310 MPa 46 x 103 psi
Tensile Strength: Ultimate (UTS)
490 MPa 72 x 103 psi
Tensile Strength: Yield (Proof)
300 MPa 43 x 103 psi
Thermal Properties
Latent Heat of Fusion
290 J/g
Maximum Temperature: Corrosion
470 °C 880 °F
Maximum Temperature: Mechanical
1100 °C 2010 °F
Melting Completion (Liquidus)
1440 °C 2630 °F
Melting Onset (Solidus)
1400 °C 2550 °F
Specific Heat Capacity
480 J/kg-K 0.11 BTU/lb-°F
Thermal Conductivity
17 W/m-K 9.8 BTU/h-ft-°F
Thermal Expansion
11 µm/m-K
Electrical Properties
Electrical Conductivity: Equal Volume
2.2 % IACS
Electrical Conductivity: Equal Weight (Specific)
2.6 % IACS
Otherwise Unclassified Properties
Base Metal Price
14 % relative
Density
7.7 g/cm3 480 lb/ft3
Embodied Carbon
2.9 kg CO2/kg material
Embodied Energy
41 MJ/kg 18 x 103 BTU/lb
Embodied Water
160 L/kg 19 gal/lb
Common Calculations
PREN (Pitting Resistance)
30
Resilience: Ultimate (Unit Rupture Work)
100 MJ/m3
Resilience: Unit (Modulus of Resilience)
220 kJ/m3
Stiffness to Weight: Axial
15 points
Stiffness to Weight: Bending
25 points
Strength to Weight: Axial
18 points
Strength to Weight: Bending
18 points
Thermal Diffusivity
4.6 mm2/s
Thermal Shock Resistance
16 points
Alloy Composition
Among wrought stainless steels, the composition of S44627 stainless steel is notable for containing a comparatively high amount of chromium (Cr) and including niobium (Nb). Chromium is the defining alloying element of stainless steel. Higher chromium content imparts additional corrosion resistance. Niobium is primarily used to improve yield strength, particularly at elevated temperatures.
| Fe | 69.2 to 74.2 | |
| Cr | 25 to 27.5 | |
| Mo | 0.75 to 1.5 | |
| Ni | 0 to 0.5 | |
| Mn | 0 to 0.4 | |
| Si | 0 to 0.4 | |
| Nb | 0.050 to 0.2 | |
| Cu | 0 to 0.2 | |
| P | 0 to 0.020 | |
| S | 0 to 0.020 | |
| N | 0 to 0.015 | |
| C | 0 to 0.010 |
All values are % weight. Ranges represent what is permitted under applicable standards.
Followup Questions
Similar Alloys
Further Reading
ASTM A479: Standard Specification for Stainless Steel Bars and Shapes for Use in Boilers and Other Pressure Vessels
ASTM A182: Standard Specification for Forged or Rolled Alloy and Stainless Steel Pipe Flanges, Forged Fittings, and Valves and Parts for High-Temperature Service
ASTM A240: Standard Specification for Chromium and Chromium-Nickel Stainless Steel Plate, Sheet, and Strip for Pressure Vessels and for General Applications
Welding Metallurgy and Weldability of Stainless Steels, John C. Lippold and Damian J. Kotecki, 2005
ASTM A959: Standard Guide for Specifying Harmonized Standard Grade Compositions for Wrought Stainless Steels
Pressure Vessels: External Pressure Technology, 2nd ed., Carl T. F. Ross, 2011
Corrosion of Stainless Steels, A. John Sedriks, 1996
ASM Specialty Handbook: Stainless Steels, J. R. Davis (editor), 1994
Advances in Stainless Steels, Baldev Raj et al. (editors), 2010