Ferrite test in Austenitic Stainless Steel.

[hvdesai1284]

DEAR ALL,
Our normal practice for checking ferrite content in Austenitic s.s is before heat treatment.I want to inform you that we are doing Solution Annealing at 1040°C for Austenitic stainless steel(i.e.A403 WP304L,WP316L) pipe fittings.so can anyone guide me why we are performing this ferrite testing before heat treatment.
If we check the ferrite content after Heat treatment,can we achieve the ferrite content in between 3 to 10% or this value will fall below 3% ???? can you provide me any reference code to justify the same? I cannot find any comment in code for doing the ferrite content test specifically before or after heat treatment.

 

[metengr]

so can anyone guide me why we are performing this ferrite testing before heat treatment.

Because your first sentence indicates your organization performs this as your normal practice.

Determination of ferrite content in austenitic stainless steels is typically based on customer specification requirements for end use.

 

[bhollands]

If you want to know the ferrite content of the stainless steel that you are providing to your customer you should check it after heat treatment. Checking it before heat treatment is just giving you a number to put on a report.

Weather the parts will have a low ferrite after heat treatment will depend on the chemistry of material. In particular the Cr and nitrogen balance. How are you checking the ferrite?

Bob

 

[EdStainless]

The final value will depend on both chemistry and the anneal. Wit any of these alloys well annealed material should be <.5% without any trouble.
How you are checking is a good question. Surface condition, probe tip diameter, and field strength all will be significant factors.

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Plymouth Tube

 

[Guest102023]

EdStainless is correct, expect little or no ferrite unless it is a casting or a weld (in which case it is not normally heat treated again).

My weapon of choice is the Fischer FerritScope.

 

[TomEun]

The ferrite contents of ASS (austenitic stainless steel) after successful solution heat treatment may be nil. The purpose of ferrite control, 3-10% is to avoid the solidification crack during welding. It means the ferrite control, such as 3-10% is not applicable to the solution heat treated products. Please be aware the best corrosion resistance of ASS as a final product can be obtained from 100% austenitic structure (zero ferrite contents).

Thomas Eun

 

[hvdesai1284]

Dear All,
sorry for replying too late.
For "metengr" - yes,we are the manufacturer of pipe fittings,in which the ferrite test is normally done for AUSTENITIC S.S.and our normal practice to check the same is before heat treatment.

FOR "bhollands" we are checking the ferrite content with using FISCHER FERRITSCOP.

Finally thank you ALL especially "Thomas Eun" for giving such aggod explanation.

 

[hvdesai1284]

Dear All,
sorry for replying too late.
For "metengr" - yes,we are the manufacturer of pipe fittings,in which the ferrite test is normally done for AUSTENITIC S.S.and our normal practice to check the same is before heat treatment.

FOR "bhollands" we are checking the ferrite content with using FISCHER FERRITSCOP.

Finally thank you ALL especially "Thomas Eun" for giving such a good explanation.