Skip to main content

RE: [MW:23299] Welding & pwht time difference in P-91 Material

By Materials & Welding
Pradip,
 
Delaying 14 days would be way too long. Surrounding environment, humidity, pollution level, salinity all needs to be considered. Original development and welding practices for this alloy called for immediate PWHT following welding. However over the years ,control of welding practices, e.g  using strictly H4 grade consumables for SMAW, H5 grade flux for SAW, have allowed  some flexibility to the fabricators through  deferment of PWHT  but not to the extent of 14 days.
 
If  fabrication and PWHT sequences makes it mandatory to defer  PWHT then dehydrogenation treatment is a must.Please see the extract from Alstom paper. 
 
Hardness levels of as welded Gr-91 steel would be easily 350HV or more. Leaving such components outdoor,without  performing PWHT for extended period  would aggravate the scenario, through cracking by SCC.
 
If at all the PWHT is deferred , it should not be more than 3-5 days at the most , subject to  environmental conditions as above  are deemed satisfactory.
 
Thanks.
 
Pradip Goswami, P.Eng,IWE
Welding & Metallurgical Engineer/Specialist
Ontario, Canada
pgoswami@quickclic.net
pradip.goswami@gmail.com
 

***************************************************************************************************************************************************************** 

From: materials-welding@googlegroups.com [mailto:materials-welding@googlegroups.com] On Behalf Of pradip kumar Sil
Sent: Monday, May 18, 2015 6:52 AM
To: materials-welding
Subject: [MW:23297] Welding & pwht time difference in P-91 Material

 

Dear All,

Can anybody inform code reference in B-31.1 welding & pwht time diference. Client is asking for 14 days.

Is it mandatory in code

--
You received this message because you are subscribed to the Google Groups "Materials & Welding" group.
To unsubscribe from this group and stop receiving emails from it, send an email to materials-welding+unsubscribe@googlegroups.com.
To post to this group, send email to materials-welding@googlegroups.com.
Visit this group at http://groups.google.com/group/materials-welding.
To view this discussion on the web visit https://groups.google.com/d/msgid/materials-welding/CAB%3DAs8%3D5YTF7j9_HXs5PJzN2GMNjA8qZrrEAti7aO8ca4bCWTg%40mail.gmail.com.
For more options, visit https://groups.google.com/d/optout.

No virus found in this message.
Checked by AVG - www.avg.com
Version: 2015.0.5941 / Virus Database: 4342/9810 - Release Date: 05/18/15

--
You received this message because you are subscribed to the Google Groups "Materials & Welding" group.
To unsubscribe from this group and stop receiving emails from it, send an email to materials-welding+unsubscribe@googlegroups.com.
To post to this group, send email to materials-welding@googlegroups.com.
Visit this group at http://groups.google.com/group/materials-welding.
To view this discussion on the web visit https://groups.google.com/d/msgid/materials-welding/BY2PR03MB2850F41F242FFC1C82EC353A1C40%40BY2PR03MB285.namprd03.prod.outlook.com.
For more options, visit https://groups.google.com/d/optout.

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