Preheat temp---250 deg celsius
Interpass max---250
Post heating --300 at 2hrs
THANKS & BEST REGARDS,
KG.PANDITHAN, BE, IWE, CSWIP 3.1,
ASNT-Level II in PT,MT,RT & UT.
International Welding Engineer.
CONSULTANT-WELDING & QUALITY
Mobile no: +919940739349
On Wed, Oct 24, 2018 at 8:55 AM Ramin Kondori <raminkondori@gmail.com> wrote:
Before I respond to your post, if you or your organisation does not have previous experience with P91/P92, I highly recommend you to seek official consultancy for this job.But about your query, here are some general guidelines:Regarding WPS parameters,
- You have to maintain pre-heat & inter-pass temp above 250 C (at least). For materials in this group, relatively high pre-heat & inter-pass temps are recommended which will normally reduce the weldability issues (cracking etc.) so don't be afraid to raise these parameters.
- On the other hand, current/voltage should be set to keep heat input high. Do not waste your time on small diameter welding filler metal. It is better to finish welding as fast as possible.
- If welding had to be interrupted, post-heating is normally required (should not leave the weldment to cool in air). This brings up the PWHT requirement. Stress relief is essential and even you may have to apply ISR (depending on actual thickness range in your particular job), which in your case means that "immediately" after reaching half thickness (30mm), it's better to stress relief the test coupon and then you may proceed with welding up to full thickness. Whatever you do, try to reduce the cooling rate of the weldment.
Why don't you use the original material (60 mm thickness)...?Nothing wrong with machining it down to 30 mm thickness but the original 60 mm material will give you more useful & realistic data to work with.Please keep in mind the following:P92 is a new revision to P91 and it has not been in service long enough so that we can choose welding parameters with high confidence. Even P91 represents a lot of challenges for welding engineers these days and is not "a walk in the park" but you can find useful information about welding P91 which shall be acquired first...Therefore, you must be very careful and use every single tool in your disposal to control the parameters. Keep preheat & interpass temperatures high; be very critical on interruptions in welding (when you start a joint, keep on welding until you complete it), be super critical on PWHT immediately after welding; keep heat input as high as you can and there is more... You should be very careful with chemical analysis of each weld pass and take dilution into account (e.g. the root pass shall be treated different than filling passes).P92 requires careful monitoring of N/Mn/Ni/Cb/V/B/W content in weld deposit and you may not be able to "copy" P92 chemical analysis into you weld deposit. Each of these elements have great effect on final properties of the weldment. Sometimes engineers use different filler metals. It is not easy to get satisfactory results in first PQR coupon.If you are new to this material group (P91/P92), I recommend you to study P91 first and when you felt that you know what you are dealing with, then do some research on P92. Again, If you do not have enough welding experience with P91, maybe it is better to ask for official welding engineering consultancy from a reputed company. You can also find very useful information by simply googling "P91/P92 Welding".P.S. I remember a few years ago, Mr. Pradip shared a very good set of guidelines for welding P91 in this very group. That will definitely help you.RegardsRamin KondoriSr. QA/QC & Welding Engineer-----------------------------------------------------------PG-Dip. in Welding Engineering (IWE AT 0070)BSc. in Civil Engineering (IUT)BGAS Painting InspectorASNT Level I&II--On Tue, Oct 23, 2018 at 1:46 PM Saravanan Sornam <saravanshyla@gmail.com> wrote:Dear Sirs ,--We are going to weld elbow to elbow of 16" Long Radius in production joint of material A182-F92, thk 60 mm, OD 406.4.As we could not able to order the Pipe material for PQR urgently, we are going to machine forging material A182 - F92, which is to be machined to Min. 30 mm Thk and OD of approx 200 mm, for safer side.I also checked about welding consumables, for GTAW - Metrode 9CrWV & FCAW - SuperCore F92 from Metrode, but could not find the parameters.As this is the 1st time, we are going to run this type of material for PQR, can you share your valuable info about the AWS Class, Bevel Prep, correct Welding Parameters, Preheat & Post Heat, PWHT requirements to control hardness, other the ASME II C code info.Thanks and Regards,Saravanan Sornam,Suwon, Korea
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