Spheroidization(?) in Type 405 Ferritic Stainless Steel

[Guest102023]

I'd like to hear thoughts on what kind of temperature is required to cause what I am certain is spheroidization. The exposure time is decades. See attached.

"If you don't have time to do the job right the first time, when are you going to find time to repair it?"

 

[metengr]

Typically, annealing at 1200-1500 deg F followed by quenching is performed on 405 stainless steel because this grade is not hardened by conventional heat treatment. Frankly, what you have are carbides in ferrite with no spheroidization. I would be more concerned with embrittlement upon exposure to elevated temperature for prolonged periods.

 

[weldstan]

Agree with metengr.

 

[Guest102023]

This is the fracture surface. Any thoughts on what appear to be deformation twins?

"If you don't have time to do the job right the first time, when are you going to find time to repair it?"

 

[metengr]

Looks like a brittle fracture surface with mostly secondary cracks in the ferrite.