09 - Metallic protection tube

The tubes are closed at one end by welding or soldering and usually threaded at the other end for adaptation to the head.


They are available in various diameters , the most used being 21.3 and 26.7 mm .

Materials commonly used :

Material	Maxximun T	Comments
Carbon Steel or Black Iron	540 °C	Satisfactory in non-corrosive atmospheres
Ductile Iron Pearlitic	700 °C	Typically used in non-ferrous
304 stainless steel	850 °C	Good corrosion resistance , can be used in oxidizing atmosphere , reducing , neutral and vacuum. the use in the presence of sulfur or reducing flame is not recommended.
316 stainless steel	850 °C	Higher corrosion resistance than 304 stainless steel . Good resistance to acids and alkalis
Stainless steel 310	1100 °C	Good oxidation resistance properties at high temperatures. Usable in oxidizing atmosphere , reducing , neutral, or in vacuo. Good for use in sulphurous atmosphere.
Chrome steel 446	1100 °C	Excellent resistance to oxidation and corrosion and high temperatures , good resistance to sulfur atmospheres.
Inconel 600	1150 °C	Excellent resistance to oxidation at high temperatures. Its use in atmospheres containing sulfur above 500 ° C should be avoided.