What is the best material for boiler tubes - Stainless or Titanium? 4

[Harold007]

I have a small diesel boiler, with steel coils which only last 12 months. If I change the material, which is best Stainless 316 or Titanium GR2? Or do any of you have any other recommendations? The tube size is 20mm, working pressure is 350Bar at 90 Deg Cel. Thea pplication is hot water for a high pressure water cleaner.
Thanks

 

[chicopee]

Sorry a little late for the reply. It seems like external stress on the weldment; crack could be due to expansion and contraction of the tubing and not so much a case for corrossion or type of material.