Stainless Steel Grade Selection for Flanges: 304 vs 316 vs 321 vs 347

Choosing the right stainless steel grade is critical for flange performance in your specific application. The wrong material can lead to premature failure, corrosion, and costly downtime.

Common Stainless Steel Grades for Flanges

304/304L Stainless Steel

• Composition: 18% Cr, 8% Ni
• Features: Excellent corrosion resistance, good formability
• Temperature Range: -196°C to 800°C
• Applications: Food processing, chemical, water treatment
• Standards: ASTM A182 F304/F304L, EN 1.4301/1.4307

316/316L Stainless Steel

• Composition: 16% Cr, 10% Ni, 2% Mo
• Features: Superior chloride resistance, marine grade
• Temperature Range: -196°C to 850°C
• Applications: Marine, offshore, chemical processing
• Standards: ASTM A182 F316/F316L, EN 1.4401/1.4404

321 Stainless Steel

• Composition: 18% Cr, 10% Ni, Ti stabilized
• Features: Excellent intergranular corrosion resistance
• Temperature Range: -196°C to 900°C
• Applications: High-temperature service, exhaust systems
• Standards: ASTM A182 F321, EN 1.4541

347 Stainless Steel

• Composition: 18% Cr, 10% Ni, Nb stabilized
• Features: Superior high-temperature strength
• Temperature Range: -196°C to 900°C
• Applications: Power generation, petrochemical
• Standards: ASTM A182 F347, EN 1.4550

Material Selection Guide

Application	Recommended Grade
Food & Beverage	304/304L
Marine/Offshore	316/316L
High Temperature	321/347
Chemical Processing	316L/904L
Cryogenic	304L/316L