SS 304 vs SS 316: The Definitive Comparison
SS 304 and SS 316 are the two most popular stainless steel grades worldwide, accounting for over 65% of all stainless steel production. While they share many characteristics, their differences can be critical depending on your application.
Chemical Composition
The primary difference lies in the addition of molybdenum in 316:
- SS 304: 18-20% Chromium, 8-10.5% Nickel, no Molybdenum
- SS 316: 16-18% Chromium, 10-14% Nickel, 2-3% Molybdenum
This 2-3% molybdenum addition in 316 significantly enhances its resistance to pitting and crevice corrosion, especially in chloride-containing environments.
Corrosion Resistance
304 performs well in most atmospheric and mild chemical environments. However, it is susceptible to pitting in chloride solutions above ~200 ppm and to stress corrosion cracking at elevated temperatures.
316 excels in marine, coastal, and chloride-rich environments. Its PREN of ~25 (vs ~18 for 304) makes it the go-to choice for pharmaceutical, marine, and chemical processing applications.
Cost Comparison
316 typically costs 20-30% more than 304 due to the higher nickel and molybdenum content. However, in corrosive environments, the higher upfront cost is often justified by longer service life and lower maintenance.
When to Choose 304
- Food and beverage processing equipment
- Architectural and decorative applications
- Kitchen equipment and appliances
- Indoor chemical handling (mild acids)
- Water treatment systems (low chloride)
When to Choose 316
- Marine and coastal installations
- Pharmaceutical manufacturing
- Chemical processing with chlorides
- Surgical instruments and implants
- Desalination plants
Available Forms at Stancor Alloys
We supply both SS 304/304L and SS 316/316L in plates & sheets (0.5-200mm thick), pipes (seamless and welded), and round bars (3-500mm diameter). All materials are supplied with EN 10204 3.1 mill test certificates.