RE: Fwd: [MW:11555] Reheating Cracks

Hi Folks,

 

After all this forum is accessed by persons from from various continents and people try to put serious and meaningful answers. To many technical personnel the answer provided below would not make any sense. May be for  a light hearted response as below why not use your personal email.

 

Looking at the problem API-934A (2008) has  detailed guidelines  on how to perform TOFD on reactors to detect reheat cracks. The important clauses are :-

1. A.5.1 ,TOFD UT -Including Table A.1—TOFD Guideline for Identifying Transverse Reheat Cracks

The TOFD technique has to be demonstrated on  a series of 4 mm × 4 mm × 0.4 mm vertical, transversely oriented embedded EDM notches at defined depths. The procedure shall be well established to detect finer well dispersed cracks like reheat cracks.

To the best of my knowledge, reheat cracking on the reactors had been a very serious issue, around,2008, as a result of which API 934A was amended.API -934A, have nice illustrations on reheat cracks , with morphologies such as:-

— subsurface in SAW weld deposits; transverse and perpendicular or at a slight angle to the surface and may have slight branching;

— occurring in circumferential, longitudinal, and nozzle welds;typically very small crack size

This problem is not a cake walk and I would think a thoroughly proven technique would be required to detect reheat cracks if any.

 

Thanks.

 

Pradip Goswami,P.Eng.IWE

Welding & Metallurgical Specialist & Consultant

Ontario,Canada.

Email-pgoswami@sympatico.ca,

pgoswami@quickclic.net

 

---

From: materials-welding@googlegroups.com [mailto:materials-welding@googlegroups.com] On Behalf Of pinaki boxi
Sent: Thursday, June 30, 2011 8:24 AM
To: materials-welding@googlegroups.com
Subject: Fwd: Fwd: [MW:11546] Reheating Cracks

---------- Forwarded message ----------
From: JALADHAR JENA <jdjena2006@yahoo.co.in>
Date: Thu, Jun 30, 2011 at 5:15 PM
Subject: Re: Fwd: [MW:11519] Reheating Cracks
To: pinaki boxi <boxi.pinaki@gmail.com>

Mr,

  this is very silly question and level -1 candidate is sufficient to give this reply.in which block u calibrate ,in that block  you should set decibal(gain)------. if you have to check welding ( as  per asme sec-5 ,article-4)
asme block reqd. may be V1 orV2 BLOCK. Secondly for welding side drill hole is not reqd. TDH is reqd. (1.6 mm  or 3.2mm) that is depend upon procedure. if u want to check parent metal FBH is reqd( as  per asme sec-5 ,article-5) that time only v2 block is needy. angle probe 70 degree is the best detector probe for cracking.may be trans verese crack,long. crackor star crak).

 

dada , in ut  angle probe used only transverse scanning that time operator shoulnot be do zig zack scanning.if u not scan properly with angulating way u cant detect any type of volumetric defect also. that is depend upon skill operator and skill welding inspector. Any type of crack indication is very sensitive and easily detect than other defect and its echo height ,shape is looking like blasted brinjal. 

 

 

keep it up

 

 thanks and regards,

 

 

jdjena

 

( now leve-2)

---

From: pinaki boxi <boxi.pinaki@gmail.com>
To: jdjena2006@yahoo.co.in
Sent: Thu, 30 June, 2011 11:58:44 AM
Subject: Fwd: [MW:11519] Reheating Cracks

Hello Mr. UT-LEVEL3
I have to inspect 132mm thickness SAW welding, CrMoV material   according API 934 for reheating cracks using TOFD.
If I didnt get wrong, I have to calibrate the system in the ASME Block   with the SDH and then adjust the gain on API block with the notches,   right??
Another doubt is about the crack characterization... its commom to   detect some porosity, even on transversal scanning, how we will judge
some signal to be reheating crack?
Thanks for the help.

--
Thanks & Regards
Pinaki Boxi.
Deputy Manager(QA/QC)
IOT-Paradip Site
Mob-+919178466059

--
Thanks & $Regards
Pinaki Boxi.
Deputy Manager(QA/QC)
IOT-Paradip Site
Mob-+919178466059

--
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.