How to choose the right tube according to our installation

Choosing the inconel 625 round bar for a wood stove or fireplace is not a matter to be taken lightly. Although not in all cases it is necessary to be demanding in terms of the quality of these, there are examples where you should not skimp.


Ideally, each home should have a pre-installation as cannon for the inside of the house with a flue on the roof. In this installation, a simple hastelloy c276 round bar can be used, since it is insulated by the house and the chimney flue, which will avoid the generation of condensation. The different simple tubes that we can find are:

Single tube

It is convenient to clarify that not just any stainless steel tube is valid and that the quality of the stainless recommended for biomass combustion appliances is monel 400 round bar. This material is very durable and resistant to corrosion, its “stainless” design says it all. It is a slightly porous material, a fact that will influence the soot will have a harder time adhering to the walls of the tube, which will have an effect on spacing the chimney sweeping times more. This type of hastelloy c267 tube is ideal for the entire installation, although it can be complemented with galvanized steel pipe to reduce costs. The price of stainless compared to galvanized is three times more.



Single galvanized tube

This type of monel 400 tube is of lower quality than stainless, although well installed we can achieve a durable and economical installation. What we should never do with this type is to install it immediately after the stove or fireplace (this would be the first tube that comes out of the stove). The material from which it is made is steel with a high temperature bath of liquid galvanizing. The manufacturing process of hastelloy c276 plate is very simple, which consists of submerging the steel in bathtubs.

We can then say that a coating has been added to the inconel 625 tube. Although this galvanized protects the tube from corrosion, if we place it right after the stove, the high temperatures generated at the outlet of the stove (400 or 500 degrees Cº), will cause the galvanized bath it flakes or cracks, and it will go through a process in which the monel 400 plate will end up losing this protection.

Once the monel k500 round bar is in raw steel, it will begin to rust and pit (for example with the moisture of the water vapor coming from the wood). In which case can we use the simple galvanized steel tube? The correct thing would be to put one or two meters of stainless steel first, and the following ones in galvanized steel. Another drawback of the galvanized grade 2 titanium tube is that it is made of a more porous material, so that the soot costs less to accumulate on the duct walls. Here in this case we would need more maintenance.

This duct is also raw steel with a high temperature bath, but in this case the bath is glazed (vitrified) and the finish is a shiny black, which makes grade 5 titanium plate ideal for installations where the tube must be seen (wood stoves and exposed metal chimneys).