When the casting is of Stainless steel type ,which under go solution
annealing i.e. heating to 1020C and quench in water.This treatment is
given after casting is fetteled .however the defect repair can be done
after the heat treatment and with suitable welding consumable which does
not require any further S.A. treatment. as weld properties you get are w/o
SA. At the most you can only go for low temp. stress relieving say at
400-450C for longer period..
As far as duplex material you need not go for any further treatment after
weld repair.as duplex structure of Austenite and ferrite to be controlled
with SA treatment, before weld repair. and welding is to be carried with
correct consumable and processAs failure to correct welding parameter will
not give you correct proportion of Ferrite and Austenite.
As for solution annealing to get corect micro strucure You require to
control parameter like Soaking temp ,Soaking time, stablising the temp.
quenching time ,cooling bath temp..Component chemistry,loading of
component in the furnace,Uniformity of temp. in the furnace. etc
Regards
Hegde
>
> Dear Mr Hedge,
>
> For your info, the heat treatment mentioned for this kind of material
> it is not called normalising heat treatment but called solution heat
> treatment.
> What happens during this treatment (when performed well) is that all
> kind of negative micro structural issues, such as Chromium Carbides
> and Sigma Phase, will be dissolved in the material by which the base
> materials corrosion resistance properties increases. After casting
> this is required for most Stainless Steels and Duplex Stainless
> Steels. At the foundry where I work we don't specify interpass
> temperature during welding below 250 °C, which normally is required
> for such materials, only because we always execute Solution Heat
> Treatment in order to ensure that all undesirable structure contents
> will be dissolved.
>
> Best Regards,
>
> Herman Pieper
>
>
> On 17 jun, 06:35,
hegde...@isgec.com wrote:
>> > Dear Abhijeet
>>
>> Most of the welding consumables are developed to get properties in as
>> welded or PWHT below AC1 and not PWHT above AC3 Therefore the component
>> after welding should be used as welded or by PWHT such as Stress
>> relieving.
>> The moment you PWHT above AC3,causes deteoriation in weld properties.
>> For Weld with normalistion require specially developed consumables with
>> modification of weld chemistry.(Generally no body prefer)In such case
>> the
>> qualification of PQR shall be brand specified..This can be developed with
>> trilas only.
>> At Godrej steel foundry for different steel grade valves we never used
>> to
>> renormalise the casting after weld repair. (only SR)
>>
>> Regards
>>
>> Hegde P.B.
>> 09714714803
>>
>> Dear Abhijit,
>>
>>
>>
>> > For CF8m Post weld heat treatment is not mandatory.
>> > So you dont have have to worry.
>> > I was with KSB Pumps(Valve division) for 8 years In QA Dept.
>> > Muni
>>
>> > On Tue, Jun 2, 2009 at 8:55 AM, abbey kangale <
abhian...@yahoo.com>
>> wrote:
>>
>> >> Dear All
>>
>> >> I have case for CF8M casting for Valves as per B16.34 which involves
>> >> welding for internal cage fittment and ...
>> >> Foudry has done welding and then they carryout subsequent Heat
>> Treatment
>> >> 1070Deg cel.to satisfy CF8M heat treatment requirement.
>>
>> >> When we asked for WPS/PQR foundry has submitted WPS/PQR for welding
>> >> without
>> >> PWHT and PQR is qualified without Heat Treatment requirement and for
>> >> which I
>> >> had taken a objection .
>>
>> >> Can Group advise my objection rersolution and corrective action as
>> >> casting
>> >> are ready for valve asssembly for our project
>>
>> >> Abhijit
>>
>> >> ------------------------------
>> >> Explore and discover exciting holidays and getaways with Yahoo! India
>> >> Travel Click here! >
>> >> <
http://in.rd.yahoo.com/tagline_Travel_1/*http://in.travel.yahoo.com/>-
>> Tekst uit oorspronkelijk bericht niet weergeven -
>>
>> - Tekst uit oorspronkelijk bericht weergeven -
>
> >
>
Cricket on your mind? Visit the ultimate cricket website.
Enter now! --~--~---------~--~----~------------~-------~--~----~
To post to this group, send email to materials-welding@googlegroups.com
To unsubscribe from this group, send email to materials-welding-unsubscribe@googlegroups.com
For more options, visit this group's bolg at http://materials-welding.blogspot.com/
The views expressed/exchnaged in this group are members personel views and meant for educational purposes only, Users must take their own decisions w.r.t. applicable code/standard/contract documents.
-~----------~----~----~----~------~----~------~--~---
No comments:
Post a Comment