About 321 Stainless Steel Information By wilsonpipeline.com

321 Stainless Steel is a standard austenitic 18/8 stainless steel grade, (304), but stabilized by Titanium. The titanium within means the stainless steel is intergranular corrosion resistant after heating, (between 425-900 degrees Celsius). Remarkably high strength as well as scaling resistance and phase stability set 321 Stainless Steel apart from other similar grades. This grade is not, however, recommended for welding consumable, as the titanium component does not allow good transfer of heat across a high temperature arc.

Chemistry

	Cr	Ni	Mo	Cu	Ti	C	Mn	Si	P	S	N	Fe
MIN	17.0	9.0	–	–	5x(C+N)	–	–	0.25	–	–	–	–
MAX	19.0	12.0	0.75	0.75	0.7	0.08	2.0	1.0	0.04	0.03	0.1	Balance

Specifications

AMS 5510, AMS 5645
ASME SA 240, ASME SA 312, ASME SA 479
ASTM A 240, ASTM A 276, ASTM A 276 Condition A, ASTM A 276 Condition S, ASTM A 312, ASTM A 479
EN 1.4541
GE B50T1181, GE B50T12, GE B50T81
QQS 763, QQS 766d
UNS S32100
Werkstoff 1.4541

Inventory

321 Stainless Steel Bars, 321 Stainless Steel Angle Bars, 321 Stainless Steel Flanges, 321 Stainless Steel Tubes & 321 Stainless Steel Pipe Fittings

Common Trade Names

321, 321 Stainless Steel, Alloy 321

Features

• Oxidation resistant to 1600°F
• Stabilized against weld heat affected zone (HAZ) intergranular corrosion
• Resists polythionic acid stress corrosion cracking

Applications

• Aircraft piston engine manifolds
• Stainless Steel Pipe Fittings
• Ball Valves
• Thermal oxidizers
• Refinery equipment
• Stainless Steel tubes
• Expansion joints
• High temperature chemical process equipment

Physical Properties

Density: 0.286 lb/inch3 
Melting Point: 2550 – 2600°F

Temperature, °F	200	400	800	1000	1200	1400	1600
Coefficient* of Thermal Expansion, in/in°F x 10-6	9.3	9.4	10.0	10.3	10.6	10.9	11.1
Thermal Conductivity Btu • ft/ft2 • hr • °F	8.8	9.7	11.4	12.1	–	–	–
Modulus of Elasticity, Dynamic psi x 106	28.0	26.5	23.8	22.5	21.2	19.7	–

Mechanical Properties

Average Elevated Temperature Tensile Properties

Temperature, °F	68	400	600	800	1000	1200	1400
Ultimate Tensile Strength, ksi	84	62	62	62	59.5	45.5	27.5
0.2% Yield Strength, ksi	38	20.5	18	17	16.5	16	14

Average Stress for Rupture

Temperature, °F	1050	1100	1150	1200	1250	1300	1350	1400	1450	1500
1,000 hours, ksi	–	30	–	19	–	11.2	–	6.8	–	4.0
10,000 hours, ksi	31	23.5	17.3	12.9	9.7	7.2	5.4	4.0	3.05	2.3
100,000 hours, ksi	23	16.5	12	8.7	6.3	4.6	3.3	2.45	1.75	1.27

Average Stress for Secondary (minimum) Creep Rate

Temperature, °F	1050	1100	1150	1200	1250	1300	1350	1400	1450	1500
1% in 1,000 hours, ksi	30	20	13.1	8.8	5.8	3.85	2.55	1.7	1.13	0.75
1% 100,000 hours, ksi	13.6	9.2	5.9	3.9	2.55	1.7	1.1	0.74	0.48	0.32

Electrical Resistivity

Temperature, °F	68	212	392	752	1112	1472	1652
ohm circ mil/ft	430	470	515	600	670	725	760

* 70°F to indicated temperature.

Source: wilsonpipeline Pipe Industry (www.wilsonpipeline.com)

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