SS 347 Welding & Carbide Precipitation
SS 347 Welding & Carbide Precipitation
(OP)
I am familiar with the issues around sensitization by welding of stabilized SS347, but I have had no direct experience with metallography or failure investigations.
(1) What features am I looking for in the HAZ?
(2) What do the carbides have to look like in terms of size and distribution for me to know I have a possible sensitization issue?
(3) In the stabilized condition, what do the Nb(C,N) particles look like - anything like the Ti(C,N) particles I am more familiar with?
Any good references on this subject?
Thanks in advance.
(1) What features am I looking for in the HAZ?
(2) What do the carbides have to look like in terms of size and distribution for me to know I have a possible sensitization issue?
(3) In the stabilized condition, what do the Nb(C,N) particles look like - anything like the Ti(C,N) particles I am more familiar with?
Any good references on this subject?
Thanks in advance.
"If you don't have time to do the job right the first time, when are you going to find time to repair it?"





RE: SS 347 Welding & Carbide Precipitation
If the carbides are along the grain boundaries you are in trouble, they should be fairly small and well dispersed.
You will be able to identify them in a polished and etched sample.
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P.E. Metallurgy, Plymouth Tube
RE: SS 347 Welding & Carbide Precipitation
RE: SS 347 Welding & Carbide Precipitation
Is there an ASTM corrosion test to evaluate possible sensitization?
"If you don't have time to do the job right the first time, when are you going to find time to repair it?"
RE: SS 347 Welding & Carbide Precipitation
"If you don't have time to do the job right the first time, when are you going to find time to repair it?"
RE: SS 347 Welding & Carbide Precipitation
2nd comment - typically, ASTM A 262 is used to evaluate sensitization of austenitic material which has been in service or after fabrication.
RE: SS 347 Welding & Carbide Precipitation
I can see a few large inclusions that are possibly Nb(C,N) from stabilization. What would be the likely makeup of the band of fine precipitates?
BTW this section was etched with oxalic acid.
"If you don't have time to do the job right the first time, when are you going to find time to repair it?"
RE: SS 347 Welding & Carbide Precipitation