Cr is low, hence carbide will form, which even solution annealing can not deal with much. You have wrong supplier.
--- On Mon, 12/7/10, Vaidehi Ganesan <vaidehi@igcar.gov.in> wrote:
From: Vaidehi Ganesan <vaidehi@igcar.gov.in> Subject: Re: [MW:5951] Inservice failure To: materials-welding@googlegroups.com Date: Monday, 12 July, 2010, 2:21 PM
It looks like carbides are formed initially. Yes. It is required to do suitable solution annealing treatments to dissolve the carbides in solid solution. Moreover the impurities (P, S, Si ) segregate along the grain boundaries (during service) and reduces the fracture toughness of the material/ weld. We have faced similar problems with HP turbine blades. Failure must be due to carbide precipitation ( fairly big sizes) and segregation of minor elements along G.B. All the best, Thank you, Vaidehi Ganesan. ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- ----- Original Message ----- Sent: Mon, Jul 12, 10 12:49 Subject: Re: [MW:5947] Inservice failure
Dear Vaidehi, The failed sample at the region of shearing or cracking has got Micro tested & found carbide precipitation in the Heat affected zone . the suraface above welding which is 20 mm far from welding is found ok in Micro. Weather the requirement of solution annealing after welding? as the tube was solution annealed previously. Pankaj
On Sun, Jul 11, 2010 at 5:51 PM, pankaj abhang <pankaj.abhang1@gmail.com> wrote:
On Sun, Jul 11, 2010 at 5:42 PM, pankaj abhang <pankaj.abhang1@gmail.com> wrote: Dear Vaidehi, Sorry for previous data incorrectly sended. Please find the actual values:- The Chemistry for the Tubes as given below The Material Grade is- SA249 TP 304. C (MAX)- 0.08 Observed- 0.054 Mn (Max)- 2.00 Observed- 1.14 P (Max)-0.045 Observed-0.033 S (Max)-0.030 Observed- 0.006 Si (Max)-1.00 Observed- 0.42 Cr (Max-20 Min-18) Observed- 18.07 Ni (Max-11- Min -08) Observed- 8.21 Observed UTS Values- 651.4(Mpa) Elongation- 62 mm Hardness- 69-70 Micro- ASTM Grain size No.7 Heat Treatment- Solution annealed at minimum 1040 celcius & rapidly water quenched. PANKAJ
On Sun, Jul 11, 2010 at 4:14 PM, Vaidehi Ganesan <vaidehi@igcar.gov.in> wrote: What is the material, compositions? best regards, Vaidehi Ganesan. ============================================================= Dr. Vaidehi Ganesan, Metallurgy & Materials Group, IGCAR, Kalpajkkam-603 102, India. ======================================================= ----- Original Message ----- Sent: Sat, Jul 10, 10 10:15 Subject: [MW:5924] Inservice failure
Dear Members, We had supplied a Finned tube radiator after 1 year in service the header to tube joint getting shearing off near 10-15 mm from weld joint. what will be the reason for the failure. Details are as given below- Tube inside process fluid- Steam at 200 celcius Tube MOC- SA 240 TP 249 Tube Thickness-2 mm Header pipe -3"NB sch10s Header MOC- SA 240 TP 312 Welding Joint- UW 16.1(d) Welding Technique- GTAW Working pressure- 15 bar(g). PANKAJ -- 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 virus found in this incoming message. Checked by AVG - www.avg.com Version: 9.0.830 / Virus Database: 271.1.1/2997 - Release Date: 07/12/10 00:06:00 -- 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.
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