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AISI 9255
Category Steel
Class Alloy steel
Type Standard
Common Names Silicon-manganese steel
Designations  France: AFNOR 55 S 7
Germany: DIN 1.0904
Italy: UNI 55 Si 8
Sweden: SS 2090
United Kingdom: B.S. 250 A 53
United States: ASTM A322 , SAE J404 , SAE J412 , SAE J770 , UNS G92550


ElementWeight %
C  0.51-0.59 
Mn  0.70-0.95 
P  0.035 (max) 
S  0.04 (max) 
Si  1.80-2.20 

Mechanical Properties

Properties Conditions 
T (°C)Treatment
Density (×1000 kg/m3) 7.7-8.03 25  
Poisson's Ratio 0.27-0.30 25  
Elastic Modulus (GPa) 190-210 25  
Tensile Strength (Mpa) 774.3  25  annealed at 845°C  more
Yield Strength (Mpa) 486.1 
Elongation (%) 21.7 
Reduction in Area (%) 41.1 
Hardness (HB) 229  25  annealed at 845°C more
Impact Strength (J)
8.8  25  annealed at 845°C  more