321 Austenitic Stainless Steel Bar
321 cannot be hardened by thermal treatment, but strength and hardness can be increased substantially by cold working, with subsequent reduction in ductility.
Used extensively for applications where the addition of titanium and its stabilizing effect as a carbide forming element allows it to be welded and/or used within the carbide precipitation range 430oC - 870oC without the risk of intergranular corrosion. These include Food Processing, Dairy Equipment, Chemical, Petrochemical, Transport and associated industries etc.
Material non magnetic in the annealed condition, but can become mildly magnetic following heavy cold working.
N.B. Optimum corrosion resistance is achieved in the annealed condition.
|Colour Code||Stocked Sizes|
|Black (Bar end)
|Min. %||Max %|
|Titanium||5 x Carbon||0.80|
|Finish||Hot Finish||Cold Finish|
|Dia or Thickness mm||All||Up to 12.7||Over 12.7|
|Temsile Strength Mpa Min.||515||620||515|
|Yield Strength Mpa Min.||205||310||205|
|Elongation in 50mm % Min.||40||30||30|
|Tensile Strength Mpa||680||600|
|Yield Strength Mpa||500||280|
|Elongation in 50mm %||40||55|
|Impact Charpy V J||180|
|Elevated Temperature Properties|
Mechanical properties are reduced as temperature increases.
|Short - Time Tensile Tests||Tensile Strength Mpa||580||425||365||310||205||140|
|Yield Strength Mpa||240||170||150||135||105||70|
|Elongation in 50mm %||60||38||35||32||33||40|
|Creep Tests||Stress for 1% Creep
in 10,000 Hours Mpa
|Low Temperature Properties|
|Tensile Strengt Mpa||740||900||1135||1350||1600|
|Yield Strength Mpa||300||340||370||400||450|
|Elongation in 50mm %||57||55||50||45||35|
|Impact Charpy J||190||190||186||186||150|
|Stress Corrosion Cracking|
|Pitting Corrosion / Crevice Corrosion|
For optimum corrosive resistance, surfaces must be free of scale and foreign particles.|
Finished parts should be passivated.
Finished forgings should be air cooled.
Finally forgings will require to be annealed in order to obtain optimum corrosion resistance.
|Please consult your heat treater for best results.|
All machining should be carried out as per machine manufacturers recommendations for suitable tool type, feeds and speeds.
It can be welded without loss of corrosion resistance due to intergranular carbide precipitation, and post-weld annealing is not generally required, except for service in the more extreme conditions.
A post weld stabilizing treatment however, is recommended when being used at elevated temperature.
This situation changes drastically when heat is applied either in service, or during welding, especially when heating through the range 430oC - 850oC, then the carbon and chromium atoms will move (precipitate) coming together to form chromium carbide (Cr23C6), depleting the structure of chromium and its corrosion resistance.
To overcome this problem, two methods have been adopted:
Low carbon grades have insufficient carbon to deplete the chromium content generally throughout the structure, However local depletion within the weld area can still be a problem leading to some intergranular corrosion if later exposed to severe corrosive conditions.
Titanium acts as a stabilizer because the carbon has more affinity to it than it has to the chromium, thus titanium carbide is formed instead and the chromium is unaffected giving the material optimum corrosion resistance.
Interlloy believes the information provided is accurate and reliable. However no warranty of accuracy, completeness or reliability is given, nor will any responsibility be taken for errors or omissions.