Adventures with a horizontal feed May 5, 2012 1:24:09 GMT -8
Post by peterberg on May 5, 2012 1:24:09 GMT -8
Reducing excess oxygen close to zero can only been done by very complicated systems, in my view. It's next to impossible to do that by natural processes like combustion. You always are stuck with excess air at the end of the process, I've tried very hard to accomplish that goal, to no avail.
One of my knowledgeable sources gives this explanation.
To oxidize the metal in a comparatively quick way, one will need three factors: oxygen (obviously), high temperature and a low carbon environment. The first two won't burn the metal on its own, the last one has to be one of the circumstances. In fact, by a temp of 1800 F. , just a little oxygen and very low CO, carbon is extracted out of the steel, turning it into rust. Oxidized steel is taking up more space, so there are coming flakes off the surface of the metal. This phenomenon itself is known as "spalling".
So, the low CO numbers, highly appreciated in rocket mass heaters, are the cause of this inconvenience.
In the early days of the blacksmith, the iron could be turned into a stronger and harder material by heating it into the coal fire. By hammering it, heating it again etc., the iron can take up carbon from the coal fire, turning it into steel. You ought to know that, because you are using a forge in the shed.
Burning out of the steel riser or tunnel is the same process in reverse. There do exist a stainless steel which is highly resistant against spalling, it's SS 310 or SS 310S.