At waht temperature does the Heat tint occur
At waht temperature does the Heat tint occur
(OP)
We have Stainless steel piping
Application
Offshore: Oil and gas.
1) Some lines are subjecte to 85 Deg C
2) Some line are subjected to 133 Deg C and
3) Some line are subjected to 204 Deg C
4) Some line are subjected to 285 Deg C
We we peocure the material they are bright and after we fabricate them we Pickle and passivate them
My Question is
A) At what temperature the SS 316L will start getting the heat tint
B) If in any case, the heat tint is going to occur at "X" deg C and if we the end use is going to be at higher temperature, why take the trouble to Pickle at all?
Application
Offshore: Oil and gas.
1) Some lines are subjecte to 85 Deg C
2) Some line are subjected to 133 Deg C and
3) Some line are subjected to 204 Deg C
4) Some line are subjected to 285 Deg C
We we peocure the material they are bright and after we fabricate them we Pickle and passivate them
My Question is
A) At what temperature the SS 316L will start getting the heat tint
B) If in any case, the heat tint is going to occur at "X" deg C and if we the end use is going to be at higher temperature, why take the trouble to Pickle at all?





RE: At waht temperature does the Heat tint occur
The questions are sent again for clarity
We have Stainless steel piping (SS 316L)
Application: Offshore: Oil and gas.
1) Some lines are subjecte to 85 Deg C
2) Some line are subjected to 133 Deg C and
3) Some line are subjected to 204 Deg C
4) Some line are subjected to 285 Deg C
When we procure the material they are bright and after we fabricate them, we Pickle and passivate them. The color of the pipe welds are white
My Questions are
A) At what temperature the SS 316L will start getting the heat tint
B) If, in any case, the heat tint is going to occur at "X" deg C and if we the end use is going to be at higher temperature, why take the trouble to Pickle at all?
RE: At waht temperature does the Heat tint occur
You pickle because it is the correct process to follow for optimum corrosion resistance.
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Plymouth Tube
RE: At waht temperature does the Heat tint occur
heat tint is something that happens in air exposure and during welding...if it will develop in service and the service is corrosive then you've problems...
what is the service of these pipes?
Heat tint (temper) colours on stainless steel surfaces heated in air
http://www.bssa.org.uk/topics.php?article=140
S
Corrosion Protection & Corrosion Control
RE: At waht temperature does the Heat tint occur
Will there be differnet tinting behaviour based on the Carbon Content
For example, if there is a pipe thet is 316L and another 316 and another 316H and another 316LN, all subjected to same heat service, would the tinting behaviour change amongst them or would they remain same.
RE: At waht temperature does the Heat tint occur
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Plymouth Tube
RE: At waht temperature does the Heat tint occur
If using HNO3/HF This can be caused by the HNO3/HF ratio being off. The percentage HF is too high or the HNO3 is too low.
The pickling solution is too hot.
As above the time in the bath is too long.
The white is really a very light gray if the welds are the proper material. I would check and make sure the filler metal is the chemistry.
Can you comeback with your pickling procedure like concentration, time and temperature?
RE: At waht temperature does the Heat tint occur
20% HNo3
10% HF
60 Deg C
RE: At waht temperature does the Heat tint occur
If you had 20% HNO3 + 3% HF you would have what is referred to as a bright pickling solution. This solution normally used where you are attempting to keep a good finish and will do a good job on fabricated pipe.
RE: At waht temperature does the Heat tint occur
RE: At waht temperature does the Heat tint occur
http://www
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http://www.bssa.org.uk/topics.php?article=2
hope this helps
S.
Corrosion Protection & Corrosion Control
RE: At waht temperature does the Heat tint occur
· Grades with at least 16% chromium (except free machining grades), 15-25% nitric acid + 1-8% hydrofluoric acid, at 20 to 60oC for 5-30 minutes.
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S.
Corrosion Protection & Corrosion Control