Hot water cylinders, buffer vessels, and combination cylinders sold by Greentherm are all manufactured from high-grade 316L Stainless steel. But what is the difference between 316L Stainless, and the standard 2304 Duplex Stainless, and why should you chose a cylinder manufactured from 316 Stainless over Duplex?
316L Marine-Grade Stainless Steel
- A low carbon level makes 316L Stainless a more ductile steal, with better resistance to flexing and cracking.
- Exceptional weldeability. Low Carbon content makes the steel highly resistant to sensitisation and embrittlement.
- Corrosion resistant under most domestic environments. Resists attack from chlorides in water,
- Not as strong as 2304 Stainless. More metal is required to achieve the same strength, making 316L tanks slightly heavier
2304 Duplex Stainless Steel
- A harder, stronger metal, allowing the manufacturing of lighter tanks.
- Less flexible than 316L. More prone to cracking and leaking over time.
- Good weldability, however prone to sensitisation and embrittlement of the finished weld.
Conclusion
- We have found in our experience that the most likely point of failure in a hot water tank are the welds around the coil fittings, which are affected not only by the expansion and contraction of the tank, but the thermal expansion of the coil itself.
- Poor quality, brittle welds will be more prone to cracking under continuously changing loads.
- The corrosion performance of 316L under domestic conditions is better than 2304.
- The additional weight penalty when using 316L is rarely an issue with domestic installation.
- For this reason especially we have chosen 316L Stainless for our cylinders as it’s improved corrosion resistance, flexibility, weldeability and resistance to embrittlement which ensures that these critical seams will last for the life of the cylinder.
- Greentherm 316L Stainless Steel cylinders are guaranteed to be leak-proof for a period of ten years* from purchase. All our cylinders are custom manufactured to our specifications by a specialist European company.
