Dear Aly,
Use of weld metal of dissimilar chemistry and superior strength is recommended to get the desired mechanical properties after NR +SR even on a carbon steel base metal e.g. SA 516 Gr 60 or 70. The rationale is as follows:-
Typical chemical analysis SA 516/60 and SA 516/70 base metal is - C-0.21-.024, Mn-0.80-1.20.For matching electrodes, E7018, C-0.15, Mn-1.60 max. Typically the plates will be fine grained normalized while the weld is predominantly a cast structure. Heating the welds above the AC3 temperature and accelerated cooling does not cause a great improvement in mechanical properties, unless the welds have sufficient alloying elements to refine the grains. From this weld design aspect it is recommend to select welding consumables with overmatching chemistry and properties for weld joints undergoing NR.
To weld a base metal SA 516/60, of 60 Ksi nominal UTS, using welding consumable of 90 Ksi would be grossly overmatching. Probably welding consumable with nominal UTS of 80 Ksi would be more appropriate. As the service is sour service welding consumables with high strength could harm the welds. The maximum hardness requirement for sour service is 22 HRC (248HV/ 234 BHN) after SR. With SMAW(9018G) +SAW (F9P6 EGF3) combination after Normalizing and SR what're the hardness readings in vendor's PQR?
Is there any notch toughness requirement on this job? Then SA 516/70 would not support PQR for SA 516/60 base metal. SFA 5.5. does not specify impact testing/ notch toughness for 9018G weld metal. Some manufacturers may report it on the test certificate (see attached), others may not unless specially asked by clients'. If there is impact requirement then probably E-8018-D1 or D2 or D3 consumables would be preferred.
Lastly please check if there are any changes in ASME Sec-IX, in the thickness qualification rules for PWHT above upper critical temperatures such as normalizing. The issue is as follows:-
· Head: 28mm thk
· Supporting PQR for the simulation test coupon: 90mmthk
It's not stated anywhere, but as per the logic of heat treatment the head thickness and the supporting coupon plate thickness should be as close as possible. Section-IX -2010 have this clause, which may be worth looking into.
QW-403.6 The minimum base metal thickness qualified is the thickness of the test coupon T or 5⁄8 in. (16 mm), whichever is less. However, where T is less than 1⁄4 in. (6 mm), the minimum thickness qualified is 1⁄2T. This variable does not apply when a WPS is qualified with a PWHT above the upper transformation temperature or when an austenitic or P-No. 10H material is solution annealed after welding.
Thanks.
Pradip Goswami,P.Eng.
Welding & Metallurgical Engineer/Specialist
Ontario Power Generation Inc.
Email-pgoswami@sympatico.ca,
From: materials-welding@googlegroups.com [mailto:materials-welding@googlegroups.com] On Behalf Of Prabhu kumar Loganathan
Sent: Tuesday, August 24, 2010 7:31 AM
To: materials-welding@googlegroups.com
Subject: Re: Re: [MW:6683] What is the Filler metal to weld Base metal (SA516 Gr 60) to achieve weld metal tensile properties after Normalization+ Stress Relieving
Dear Aly,
E9018-G very well acceptable for welding with NR+SR for material grade SA516 Gr. 60. Based on your previous mails, it is not necessarily that all times the chemistry of filler metal should match with base materials. It may change based on other conditions such as NR.
It is understand that if CS weld undergoes heat treatment with above critical temperature (NR), there is a fall in tensile strength would take plate due to coarse grain formation of dendrite structure of the weld. This is depends on NR temperature and duration. But in any case there will be a reduction in tensile strength approximately 10-15 Ksi (100 N/mm2) in welds when compared with as welded condition. However, this will not be happened in base materials, since the metallurgical structure is different than the weld due to chemical composition with addition of some amount of alloying elements. See the attached article (Table 4 – CMn welds) would provide more details on this subject. Also refer to "Metallurgy of basic weld metal" by Evans for more details.
Hence to compensate the fall in strength after NR, we should select higher strength filler metal to achieve the strength requirements. Ideally it is preferred to use with "M" grade (Military) filler metals for welds with NR+SR. However, the filler metal used by the vessel vendor is acceptable.
Regards,
Prabhu.
On Tue, 24 Aug 2010 11:22:02 +0530 wrote
>
Dear Mr.Raghuram Bathula
Thank you for quick response.
I appreciate if you could give ASME code reference to go ahead with higher metallurgy for my satisfaction to convince my client.
Thank you once again
Aly
Kuwait
>
>
From: Raghuram Bathula
>To: materials-welding@googlegroups.com
>Sent: Tue, August 24, 2010 8:42:39 AM
>Subject: Re: [MW:6672] What is the Filler metal to weld Base metal (SA516 Gr 60) to achieve weld metal tensile properties after Normalization+ Stress Relieving
>
>yes, it is acceptable, you can select higher metallurgy to get desired mech properties, as long as no restriction w.r.t corrosiveness of the fluid.
>
>
On Tue, Aug 24, 2010 at 10:55 AM, aly mhaskar <mhaskar_aly@yahoo.com> wrote:
>
Dear Mr. Karthik / Raghuram bathula
My Question is whether thefiller metal
(SMAW with E9018-G; SFA 5.5; A=10; F no. 4 & SAW with F9P6 EG F3; SFA 5.23; A=10; F no. 6)
is acceptable to the base metal (SA516 Gr 60) as weld metal chemical properties(C=0.06%, Mn=1.37%, Si=0.24%, S% <0.005, P=0.014%, Mo=0.48%, Ni=0.82%, Cu=0.13%.) are not meeting theSA516 Gr60requirements.
Aly
Kuwait
>
>
From: Karthik <karthik6684@yahoo.com>
>To: materials-welding@googlegroups.com
>Sent: Tue, August 24, 2010 7:32:00 AM
>Subject: Re: [MW:6667] What is the Filler metal to weld Base metal (SA516 Gr 60) to achieve weld metal tensile properties after Normalization+ Stress Relieving
>
>
| Hi, I found the WPS&PQR from your Contractor have used SA516 Gr.&0(P.No.1,Gr.2) but your actual material in production is SA516 Gr.60(P.No.1,Gr.2). Change in Material Group No.is a Supplementary Essential Variable for SMAW and SAW Processes as per QW253 and QW254. Please find below the extraction from ASME Section -IX-QW403.5 for your reference. QW-403.5 Welding procedure specifications shall be qualified using one of the following: (a) the same base metal (including type or grade) to be used in production welding (b) for ferrous materials, a base metal listed in the same P-Number Group Number in table QW/QB-422 as the base metal to be used in production welding (c) for nonferrous materials, a base metal listed with the same P-Number UNS Number in table QW/QB-422 as the base metal to be used in production welding For ferrous materials in table QW/QB-422, a procedure qualification shall be made for each P-Number Group Number combination of base metals, even though procedure qualification tests have been made for each of the two base metals welded to itself. If, however, two or more qualification records have the same essential and supplementary essential variables, except that the base metals are assigned to different Group Numbers within the same P-Number, then the combination of base metals is also qualified. In addition, when base metals of two different P-Number Group Number combinations are qualified using a single test coupon, that coupon qualifies the welding of those two P-Number Group Numbers to themselves as well as to each other using the variables qualified. This variable does not apply when impact testing of the heat-affected zone is not required by other Sections.
Thanks & Regards, (karthik)
|
>
--
>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.
>
>
--
>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.
>
--
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.