The Real Cost Question: Upfront Price vs Lifetime Value
Duplex stainless steel costs 3-5x more than carbon steel per kilogram. But when corrosion costs, maintenance downtime, and production losses are factored in, duplex frequently delivers lower total lifecycle cost in aggressive environments. CoreMetal Steel supplies both materials with detailed cost comparison analysis.
Material Cost Comparison
Carbon steel (A36/A516): $800-1,200/ton. Duplex (SAF 2205): $4,500-6,000/ton. Super duplex (SAF 2507): $7,000-10,000/ton. Net fabrication premium: 2-3x (less than material ratio due to thinner sections and no coating).
Corrosion Cost Factors
Carbon Steel
Corrosion rates: rural 0.01-0.05 mm/yr, industrial 0.05-0.15 mm/yr, marine 0.10-0.30 mm/yr. Costs include coating ($30-80/m2), maintenance ($20-50/m2 every 5-15 years), monitoring, shutdowns ($50,000-500,000/day), replacement at 15-25 years.
Duplex (SAF 2205)
Essentially zero corrosion in most environments. PREN 34-38. SCC resistance 3-5x better than 304/316. Eliminates allowances, coatings, and monitoring.
Lifecycle Cost Example: Offshore Piping
30-year, 200mm, 150m seawater system:
Carbon Steel + Coating NPV: $350,000-450,000 (includes $200,000 downtime).
Duplex SAF 2205 NPV: $220,000-280,000 (no maintenance, no downtime).
Savings with duplex: $100,000-200,000 over 30 years despite 4x material cost.
Hidden Costs
Unplanned shutdowns: $100,000-$1,000,000 per event. Product contamination. Environmental compliance for coating waste. Duplex scrap recovers 15-25% of investment.
When Carbon Steel Is Right
Non-corrosive environment, short design life under 10 years, accessible for maintenance, capital constraints.
Decision Framework
1. Define environment. 2. Estimate CS corrosion rate. 3. Calculate corrosion allowance. 4. Compare initial cost. 5. Project maintenance. 6. Include production loss. 7. Calculate NPV. 8. Select lowest lifecycle cost.
CoreMetal Steel supplies both duplex and carbon steel with lifecycle cost comparisons for your specific application.