Skip to main content

Re: [MW:12554] defect on circ-seam of H2 service vessel

By Materials & Welding
The defect is visually confirmed; nothing is assumed. I want to conclude that for repair of this dimension does the code call for rehydro?

Regards
Hrishi

Sent on my BlackBerry® from Vodafone

From: "Bathula Raghuram (Mumbai - PIPING)" <R.Bathula@ticb.com>
Sender: materials-welding@googlegroups.com
Date: Tue, 27 Sep 2011 13:01:44 +0530
To: 'materials-welding@googlegroups.com'<materials-welding@googlegroups.com>
ReplyTo: materials-welding@googlegroups.com
Subject: RE: [MW:12551] defect on circ-seam of H2 service vessel

did you compare this image with the RT taken at fab shop? Did you conclude anything why it was happened?

Did you check visually and measured these dimensions or assumption from the RT image?  Images like this are possible May be due to the thickness difference of shell and dished end. If it is visually confirmed, yes repair by welding is required followed by local PWHT/NDT/hardness check and re hydro

 

From: materials-welding@googlegroups.com [mailto:materials-welding@googlegroups.com] On Behalf Of K.M Hrishikesan
Sent: Tuesday, September 27, 2011 11:44 AM
To: materials-welding
Subject: [MW:12548] defect on circ-seam of H2 service vessel

 

Dear Mr. Pradeep Goswami & other experts...

 

We have a newly fabricated Vessel having following details

 

 

Vessel:  1200 mm ID X 4550 mm TL-TL

MOC: SA 516 Gr 60

Code of constr: ASME section VIII div 1 2007 edn.

Thickness: shell-20mm; DE-24 mm

Design pr- 32.3 kg/sq.cm; Design temp - 80 deg.C

Service: LPG+Naphtha ; Vessel is designed for  Hydrogen service, 100%RT, Fully PWHT; hydrotested ,cleared by TPI, erected at site, yet to be commissioned

 

 

Imperfection (a notch or gouge out)of about 3-4 mm deep and 15 mm long observed on weld seam CS-1 (Top Dished end to shell circ. seam joint ) from inside of vessel. Please see the attached image of segment radiographed by us.

 

My queries...

 

What rectification shall I do on the defective segment on the service point of view?

What are the NDE's required?

Is a local PWHT mandatory at the repaired segment?

Any special precautions for H2 service...

 

appreciate your quick feedbacks..

 

Regards

Hrishi

 


Comments

Post a Comment

Popular posts from this blog

Heat tint (temper) colours on stainless steel surfaces heated in air // Heat tint

By Materials & Welding
Introduction The colour formed when stainless steel is heated, either in a furnace application or in the heat affected zone of welds, is dependent on several factors that are related to the oxidation resistance of the steel. The heat tint or temper colour formed is caused by the progressive thickening of the surface oxide layer and so, as temperature is increased, the colours change.   Oxidation resistance of stainless steels However, there are several factors that affect the degree of colour change and so there is no a single table of colour and temperature that represents all cases. The colours formed can only be used as an indication of the temperature to which the steel has been heated. Factors affecting the heat tint colours formed Steel composition The chromium content is the most important single factor affecting oxidation resistance. The higher the chromium, the more heat resistant the steel and so the development of the heat tint colou...
Post a Comment
Read more

Materails FAQs

By Materials & Welding
Q: What are equivalents for standard Q 235 B (and Q 235 A) for U-channels? (asked by: boris.vielhaber@vait.com) A: DIN Nr. = 2393 T.2, 2394 T.2, EN 10025 W. Nr. DIN 17007 = 1.0038 Design DIN 17006 = RSt 37-2, S235JRG2 (Fe 360 B) Q: What is St DIN 2391 BK material? (asked by: dmcandrews@automaticstamp.com) A: Precision steel tubes, cold-finished/hard. Q: What is C.D.W. Boiler Tube? (asked by: montydude123@yahoo.com) A: Cold Drawn Welded Boiler Tube. Q: WHAT IS W.Nr. 1.4301? PLS TELL US IN EASY LANGUAGUE (asked...
21 comments
Read more

The Schaeffler and Delong diagrams for predicting ferrite levels in austenitic stainless steel welds

By Materials & Welding
Introduction Ferrite is important in avoiding hot cracking in during cooling from welding of austenitic stainless steels. 'Constitution diagrams' are used to predict ferrite levels from the composition by comparing the effects of austenite and ferrite stabilising elements. The Schaeffler and Delong diagrams are the original methods of predicting the phase balances in austenitic stainless steel welds. Nickel and chromium equivalents A 'nickel equivalent' is calculated for the austenite stabilising elements and a 'chromium equivalent' ferrite stabilising elements. These are used as the axes for the diagrams, which show the compositional equivalent areas where the phases austenite, ferrite, martensite (and mixtures of these) should be present. Although intended to show the phase balance of weld fillers, these diagrams can also be used to illustrate the phase balance of the 'parent' material. There are different diagrams for dif...
Post a Comment
Read more