Article

Duplex Tube and Coiling

Manufacturers of hot water storage systems are in a highly competitive market. The need for lean manufacturing and a close eye on manufacturing and material costs is uppermost in their design criteria.

Many UK manufacturers have moved to the use of Duplex stainless steel, either LDX 2101®   or 2304 in the construction of their cylinders. These stronger stainless steels offer the opportunity to reduce the wall thickness by as much as 30% with a lower material cost and weight. The lower Nickel content can also lead to less volatile material price swings which are important when planning long term manufacturing costs.

For many years the choice of stainless steel for the manufacture of heat exchanger coils has been ASTM 316L. In recent times manufacturers have approved the use of lean alloyed Duplex LDX 2101® as an alternative in the drive to reduce material costs.

At CSi Ltd we are a specialist stainless steel coiled heat exchanger manufacturer and have been challenged by our customers to make use of Duplex stainless steels.

Because these stainless steels are “tougher” than the more malleable 316L we have had to learn new skills, not only to manufacture the tube, but also to coil this less forgiving material. The stronger Duplex material requires more mechanical strength to work with. We have therefore upgraded some machines with more powerful motors and gearing and invested in completely new machines.

When coiling stainless steel we know that it is not good enough to simply acquire stainless steel tube to the right length and industry specifications and then coil it. To successfully coil tube without quality issues during the manufacturing process, the tube must be produced to the specification suitable for coiling. This is even more important when using LDX 2101®. The only way for us to guarantee the tube met this requirement was for us to take control and manufacture our own tube.

If you would like further information, please contact us.