AISI 321

Grades 321 and 347 are the basic austenitic 18/8 steel (Grade 304) stabilised by Titanium (321) or Niobium (347) additions. These grades are used because they are not sensitive to intergranular corrosion after heating within the carbide precipitation range of 425-850 °C. Grade 321 is the grade of choice for applications in the temperature range of up to about 900 °C, combining high strength, resistance to scaling and phase stability with resistance to subsequent aqueous corrosion.

Chemical Composition

Element	Content(%)
Manganese, Mn	2.00
Nickel, Ni	9.00 - 12.00
Chromium, Cr	17.00 - 19.00
Carbon, C	-
Silicon, Si	0.75
Molybdenum, Mo	-
Sulfur, S	0.030 (max)
Phosphorus, P	0.045 (max)
Nitrogen, N	0.10

Mechanical Properties

Properties	Metric
Tensile Strength (MPa) min	515
Yield Strength 0.2% Proof (MPa) min	205
Elongation (% in 50 mm) min	40
Hardness, HRB max	95
Hardness, HB max	217

Sheets / Plates

Production Route	Hot Rolled, Cold Rolled
Material Standard	AISI, ASTM, ASME, DIN, BS, EN, ISO, JIS, GOST, SAE, IS & Custom Chemistry
Size	Width from 100mm to 3000mm ; Length from 500mm to 12000mm
Thickness	0.1mm to 400mm
Delivery Condition	As Rolled, Annealed, Quenched and Tempered, Normalized
Surface Finish	Plain, Brushed, Cladded

AISI 321 Applications

1) Structures in Buildings, bridges, railway stations.

2) Fabrication of pipeline components & Industrial equipment.

3) Construction of automotive bodies, warehouses, shipping containers.

4) Commercial appliances, etc.