IINTERGRANULAR CORROSION IN THE HEAD OF SA240-TP304L?

[1348978]

hi every body
we want to make 2 head from SA240-TP304L,ID=6000 mm, knuckle should be maked by hot spinning,(temp=900~925 degree c),can i sure any intergeranular corrosion,don't happen in this head?help me, i a'm waiting for your answer.
thanks.

 

[Metalguy]

Are you asking about SERVICE-induced IGA or during the manufacture? If the former, what is the environment, and how long will the head be exposed to temps. around 1100-1300 deg F?

 

[Cheops]

You need to seriously consider solution-annealing (heat to 1065°C then fast cooling. Because of the size of the head, cooling will have to be done by blowing air using strong fans so as to cool down the head from, say 900°C to 500°C in less than 30 minutes.

 

[rama33]

Since your material is SS 304 L it carbon will be less than 0.08 %.IGC temperature range depends according to your carbon content in the SS.Normally IGC temperature range is from 400°c to 800°c.In your case it is 900°c.It is adviced to fast cool in the IGC temperature range 400°c to 800°c.To be safe after hot spinning operation.Carryout Solution annealing at 1040 to 1060°c+fast cooling. Another test method to confirm is take a similar material simulated the same thermal cycle with the job and test as per ASME A 262 partice A.
For futher reading see

http://www.nidi.org.

Regards
rama33

 

[Metalguy]

304L has a C limit of around .035-.04, depending on the spec. REGULAR 304 is .08 max.