High chemical resistant metal sought

[Nestornotabilis]

As electrical heating of electro-galvanising bathes is waiting for an accident to happen and burn the works down we will be using metal tubes on the bottom of our process bathes. Through these will flow fluid (water) from a heat-exchanger. Therefore a high grade plastic such as PVDF is out due to poor temperature transfer.
The problem is that the bathes operate at temperatures of minimum 85 degrees C up to about 100 deg. C and are quite aggressive chemically. The pH value shifts between 0.6 to 0.9 and the main acids are combi H2SO4/HCL and HCl. There are more complex compounds involved but this will have to do due to legal requirements.
Titanium will hold out quite well in the H2SO4/HCl environment but not too good in the HCl. Hastelloy B3 is equally dissapointing in both. The material erosion is not much but we would prefer not to have to renew everything if not needed. Cost factor does play a role however, so mabee a compromise must be made.
Question is: Is there a material we should look into that can meet our requirements? or have we done that with the Hastelloy?

 

[unclesyd]

If you can get by using Teflon hear a few sites.
We didn’t use metal on any of our systems. We used Teflon Coils for heating and cooling. The Process Technology products for heating.

http://www.fluorotherm.com/immhtex.htm

http://www.process-technology.com/processtechnol/fluorohtr.htm

http://www.heatersplus.com/lufran.htm

 

[Nestornotabilis]

Your first link may be something, the other two show the construction as stainless coated with PTFE. We know in our company how good PTFE can be regarding temperatures and resistancy to chemicals, however it is not tough and durable enough as a thin coating. Sometimes products have contact with the tubing in the bathe so ..