Re: [MW:6279] Re: Solution Annealing of Stainless Steels

Dear Mr. Abhijit

Usually Sensitisation temp. range is from 425-870 c. The annealing temp. for SS 316 is 1040-1120, which is more than sensitisation range.
Time of temp. will depend upon the thickness range.
So the chances of sensitisation is less unless the amount of C content is too much, Also be careful while selecting welding consumables & welding process so that it does't add more carbon in the weld metal.

Sensitisation effect can be minimised by choosing 316L & having stabilised elements like Ti/Cb/Nb and also by rapid air or water quench in the range of 450-600.

Solution Annealing does't give guarantee of no sensitisation, If rapid cooling can't be achieved, again it will cause sensitisation.

Hope this clarifies your query.

Regards
Manpreet Singh
Welding Engineer
Spiecapag



On Tue, 03 Aug 2010 07:24:21 +0530 wrote
>Dear Abhijit,



The reason why using 316L quality instead of ordinary 316 material is

because this material is not sensitive for carbide precipitation. When

using 316L material the carbon content need to be less than 0.03% and

therefore there is less carbon to create such precipitates. So in

general you may say that from manufacturing site there is no need for

solution heat treatment when using 316L, however when the material has

undergone hot working without temperature control and the method of

heating is by way of gas burners you need to be sure that no increase

of carbon content is caused by maladjustment of the burners in the

materials surface.

If this can't be guaranteed a solution heat treatment can cause no

harm. You have to understand that in such case the material no longer

full fill the requirements of 316L material and therefore this could

be a reason for rejecting the material.

So it's not recommended and/or required to perform the solution heat

treatment but I personally never should accept hot working without

controlling the temperature and/or other conditions.



Best Regards,



Herman Pieper



On 2 aug, 18:19, Abhijit wrote:

> Dear Jeff

>

> How you define sensetization temp range and again this will depends on the time duration that material is held for and based on that only we will able to define the sensitisation and their further effect of carbide precipitation

>

> Is it recommanded to carryout solution annealing for SS316L material which undergoes hot work ,without controlling temperature and duration less than 10-20 minutes and after that natural cooling?

>

> Abhijit

>

> Sent from my iPhone

>

> On Aug 2, 2010, at 5:42 PM, Jeff wrote:



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