Re: stress relieving of joint

From: <Narendra>
Date: Wed Jun 16 2004 - 12:16:00 EDT

Dear DB Raval
The cracks you are getting may be due to stress corrosion cracking which SS316 experiences at the temperatures and stresses in chloride environments. You shpould think your self lucky that it took 15 years to show the cracks, may be due to over design of the component. Please check up the area of the crack using insitu metallography and i am sure you will have multiple cracks originating. the repairs of the cracks may also be tricky as during repairs you may experience generation of more cracks. be cautious during repairs and use the proper electrodes with as little heat input as possible. Good luck. I hope the thickness of the components will also be low ( thin sections) and the stress relieving which is not the same as for Cs but solution annealing may help but I doubt it for the older operating vessel under repairs may take those temperatures.
You may have to cut out and replace the area affected by a new piece of patch or component.
Narendra K. Roy
CGNL NZ
Camp: India
www.charismaglobal.com

• D B Raval <dbraval@tatachemicals.com> wrote:
  > Friends,
  > We have Quadruple Effect Brine Evaporator System for
  > Make Up Water Plant.The
  > operating condition is such that it is attacked by
  > chlorides at elevated
  > temperature (130 Degree Centi) and pressure of @ 1.2
  > Kg/Sq.Cm
  > The first effect Evaporator Body top dome
  > (Hemispherical Dish end) MOC: S.S
  > 316L found having a crack after service of say 15
  > Yrs.Can it be due to
  > unrelieved stresses induced during welding ???
  > Also,is it possible/advisable to stress relieve a
  > joint other than Carbon
  > Steel say in S.S-316L?
  >
  > Regards
  >
  >
  >
  >
  

  ---

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