Stainless Steel Selection: 304 vs 316 and When to Use Each

“Just use 316 to be safe.”

We hear this constantly. And while 316 stainless steel is an excellent material, defaulting to it wastes money on applications where 304 performs identically. Understanding the actual difference between these grades—and when that difference matters—can save significant cost without sacrificing performance.

The One Question That Matters

Before diving into chemistry and specifications, here’s the decision simplified:

Will this component be exposed to chlorides?

Chlorides include salt water, road salt, swimming pool chemicals, certain cleaning agents, and many industrial process fluids. If the answer is yes—or even “possibly”—specify 316. If the answer is clearly no, 304 is likely the better choice.

That’s the core of it. Everything else is nuance.

What Makes 316 Different

Both 304 and 316 are austenitic stainless steels with similar base compositions:

• ~18% chromium (provides corrosion resistance)
• ~8-10% nickel (maintains austenitic structure)
• Low carbon content (prevents sensitization during welding)

The key difference: 316 contains 2-3% molybdenum.

Molybdenum dramatically improves resistance to pitting and crevice corrosion, particularly in chloride-containing environments. This single addition justifies 316’s existence—and its 20-30% price premium.

The Chloride Problem

Chlorides are uniquely aggressive toward stainless steel. They penetrate the passive chromium oxide layer that protects stainless from corrosion, initiating pitting that can progress to perforation.

304 handles most corrosive environments well. Mild acids, most organic chemicals, and ordinary atmospheric exposure won’t challenge it. But introduce chlorides—even in small concentrations—and 304 becomes vulnerable.

Common chloride sources people overlook:

• Coastal air (even miles from the ocean)
• Road salt and de-icing chemicals
• Cleaning products containing bleach
• Cooling tower water treatments
• Food processing brines
• Swimming pool environments
• Human perspiration (yes, really)

When 304 Is the Right Choice

304 stainless steel isn’t a compromise—it’s the appropriate specification for the majority of applications:

Food Processing (non-salt) Most food contact surfaces, preparation equipment, and processing machinery use 304 successfully. Dairy, brewing, beverage, and general food manufacturing rarely require 316 unless salt or brine is involved.

Architectural Applications (non-coastal) Interior handrails, kitchen equipment, countertops, and architectural trim in inland locations perform well in 304. The material weathers attractively and resists normal cleaning chemicals.

General Industrial Equipment Tanks, piping, and equipment handling non-chloride chemicals, water, and most process fluids. 304’s corrosion resistance handles the majority of industrial environments.

Kitchen and Restaurant Equipment Commercial kitchen equipment, sinks, tables, and food storage almost universally use 304. The cost savings over 316 are significant at equipment scale.

Fasteners and Hardware (indoor) Bolts, nuts, screws, and brackets in protected environments. 304 hardware provides excellent corrosion resistance at lower cost than 316.

When 316 Is Worth the Premium

Certain applications genuinely require 316’s enhanced chloride resistance:

Marine Environments Any component exposed to salt water or salt air. Boat hardware, dock equipment, coastal architectural elements, and offshore structures. There is no substitute here—304 will fail.

Chemical Processing Equipment handling chlorides, bromides, or iodides. Pulp and paper processing (chlorine compounds), pharmaceutical manufacturing, and chemical plants often require 316.

Medical and Pharmaceutical Surgical instruments, implants, and pharmaceutical processing equipment frequently specify 316L (the low-carbon variant) for its superior corrosion resistance and biocompatibility.

Swimming Pools and Water Parks All equipment exposed to chlorinated water. The combination of chlorine, heat, and moisture creates an aggressive environment.

Outdoor Coastal Architecture Railings, facades, and structural elements within several miles of salt water. Coastal environments corrode 304 surprisingly quickly.

Road Salt Exposure Equipment, vehicles, or structures exposed to winter road salt. Transportation equipment and roadside infrastructure often require 316.

The L Variants: 304L and 316L

Both grades are available in low-carbon variants (designated with “L”):

• 304L: Maximum 0.03% carbon (vs 0.08% for standard 304)
• 316L: Maximum 0.03% carbon (vs 0.08% for standard 316)

Why it matters: During welding, carbon can migrate to grain boundaries and combine with chromium, depleting the chromium that provides corrosion resistance. This “sensitization” creates vulnerability to intergranular corrosion.

Specify L grades when:

• The component will be welded
• Post-weld heat treatment isn’t possible
• Maximum corrosion resistance is required in welded joints

For non-welded applications, standard 304 and 316 perform identically to their L counterparts.

Beyond 304 and 316

While these two grades dominate, other stainless steels solve specific problems:

303 (Free-Machining) Contains added sulfur for improved machinability. Machines faster and produces better surface finishes, but with slightly reduced corrosion resistance. Ideal for high-volume machined parts where cutting efficiency matters.

316Ti (Titanium-Stabilized) Contains titanium to prevent sensitization at high temperatures. Used in high-temperature applications where the component will be heated above 800°F in service.

17-4 PH (Precipitation Hardening) Can be heat treated to high strength levels (up to 200 ksi yield). Used where both corrosion resistance and high strength are required—aerospace, valve components, and high-performance fasteners.

Duplex Grades (2205, 2507) Combine austenitic and ferritic structures for higher strength and better stress corrosion cracking resistance than 316. Used in demanding chemical and offshore applications.

Cost Perspective

The 316 premium varies with market conditions but typically runs 20-30% over 304. On small components, this might be a few dollars. On large fabrications, it can be thousands.

Example cost impact (approximate):

Component	304 Cost	316 Cost	Premium
1” diameter rod, 6’ length	$45	$58	+29%
48” x 96” x 0.125” sheet	$380	$490	+29%
1000 pcs machined bushings	$2,400	$3,100	+29%
Custom fabricated tank	$8,500	$11,000	+29%

For applications that genuinely need 316, the premium is justified. For applications where 304 suffices, it’s waste.

Making the Call

Run through this checklist:

1. Chloride exposure? → 316
2. Marine or coastal environment? → 316
3. Medical/pharmaceutical with body contact? → 316L
4. Swimming pool or chlorinated water? → 316
5. Road salt exposure? → 316
6. None of the above? → 304 is likely appropriate

When in doubt, consider the consequences of corrosion failure. If failure creates safety issues or major expense, the 316 premium is cheap insurance. If failure means replacing a wear part, 304’s lower cost may allow for more frequent replacement.

Working With NextGen Components

We stock both 304 and 316 stainless steel in various forms. Our materials database includes full specifications for both grades, and our team can help you determine which grade fits your application.

Need a specific form factor or have questions about grade selection? Contact us with your application details.