Metal Alloys
Alloy Home
Steels
Alloy Steels
General Information
Properties
Classification
Standard
H-Steels
HSLA
Alloy Steel List
AISI 1xxx
AISI 2xxx
AISI 3xxx
AISI 4xxx
AISI 5xxx
AISI 6xxx
AISI 8xxx
AISI 9xxx
* For other AISI or Non-AISI, please use the search function above or check Grades.
ASTM Steels
Specific Alloy Steel
General Information
Resources
Bibliography
Essentials of Manufacturing

Information, coverage of important developments and expert commentary in manufacturing.

Negotiate Your Salary

Learn the best principles to negotiate the salary you deserve!

Metal 3D Printing Design Guide

Direct Metal Laser Sintering (DMLS) 3D printing for parts with reduced cost and little waste.

CNC Machining Design Guide

Optimize your designs, reduce machining time, and lower your costs.

more free publications
 
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

Composition

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)
(Izod)
8.8  25  annealed at 845°C  more
Glossary
Essentials of Manufacturing

Information, coverage of important developments and expert commentary in manufacturing.

Negotiate Your Salary

Learn the best principles to negotiate the salary you deserve!

Metal 3D Printing Design Guide

Direct Metal Laser Sintering (DMLS) 3D printing for parts with reduced cost and little waste.

CNC Machining Design Guide

Optimize your designs, reduce machining time, and lower your costs.