The surface was pickling and passivated months ago after heat treatment, but now we have the same problem. Do you know why ASTM indicated "Solutions of nitric acid alone are usually not effective for removing heavy oxide scale"? Perhaps it is necessary other type of test...
This is the question:Heat tint is expected when heat treating a 410S? Presence of this so called "scales" should not be regarded as a concern from a corrosion resistance point of view??"
The scale was eliminated months ago but one more time this scale has been found. The material is los alloy cladding 11/13 Cr and it has been treated in accordance with ASME VIII (750ºC, hold time 2 h).
This scale may affect to mechanical properties (Design Temperature 430ºC)
