🔍 Unveiling the Economical Marvel: Super Duplex Stainless Steel

Stainless steel materials are often a quantifiable advantage for the future, reducing maintenance over the entire service life and lowering life cycle costs. Particularly, high-strength duplex stainless steel can sometimes be the most cost-effective choice for initial investment! This article delves into a case study that discusses why a chimney built with 2507 Super Duplex Stainless Steel is more economical than one made of weathering steel.

🏭 The Scenario: A Sinter Plant's Dilemma

In 2017, a sintering plant's exhaust chimney partially collapsed in adverse weather. The plant, which primarily produces iron ore powder sintering materials for nearby blast furnace smelting, had a massive chimney standing at approximately 60 meters tall with a diameter of 3.7 meters. Originally designed with a double layer comprising a 6mm thick weathering steel inner wall, an insulation layer, and a galvanized steel outer layer, the chimney faced premature aging of its insulation layer in the harsh coastal industrial conditions.

🌪️ The Challenge: Corrosion and Maintenance

The chimney's triple-layer design, while protective, became challenging to inspect and maintain due to its complexity. With a service life not reaching the expected 20 years, various replacement designs with enhanced corrosion resistance were evaluated. Two stainless steel solutions capable of withstanding condensate corrosion were identified as the best combination of simplicity, replacement speed, and service life.

💰 The Economic Breakdown

Super Duplex, with its higher strength and lower alloy cost, emerged as the lowest-cost solution. Compared to the original design, all alternative designs offer stronger corrosion resistance, each with its own pros and cons. The 2507 Super Duplex Stainless Steel, with its superior corrosion and strength, allows for a thinner wall, significantly reducing material use and cost.

🏗️ The Implementation

The chosen replacement, a single-layer chimney made from 2507 Super Duplex Stainless Steel, began construction in 2019. The chimney, fabricated from 6mm to 10mm thick stainless steel cold-formed plates welded into massive rings, was assembled on-site, offering a simpler and more robust solution than its double-layer predecessor.

🌐 The Long-Term Outlook

Since its installation, the chimney has operated without issues, expected to provide low-maintenance service for the next 30 years or more. The case study illustrates that the high strength and excellent corrosion resistance of duplex stainless steel not only reduce weight but also save costs immediately. As one of the most recyclable materials on Earth, part of the initial investment can be recovered as scrap value at the end of its service life.