Chemical Tanker Stainless Steel: 316L vs. 2205 vs. 1.4466

 

Why 316L remains standard for mild chemicals?
Handles 93% sulfuric acid at ambient temperatures. Cost-effective for non-oxidizing cargoes like phosphates or glycols. Permitted by IMO Type 2 tanker specifications.

 

When is duplex 2205 mandatory?
For nitric acid (>40%) and caustic soda (>50%) transport. PREN 35+ prevents stress corrosion cracking during thermal cycling. Required for IMO Type 1 hazardous cargoes.

 

Advantages of super duplex 1.4466?
Resists chlorinated solvents (EDC, VCM) at 60°C. Higher pitting resistance (PREN 43) than standard 2205. Allows thinner liners (4mm vs 6mm) increasing payload capacity.

 

Cargo compatibility testing protocols?
30-day immersion tests per ASTM G31 at maximum operating temperature. Electrochemical testing for critical anodic breakdown potentials. U-bend SCC tests in vapor phase.

 

In-service inspection requirements?
Ultrasonic thickness mapping after each cleaning cycle. Dye penetrant testing of welds every 2 years. Hull stress monitoring during cargo operations to detect microfractures.