[MW:23300] Welding & pwht time difference in P-91 Material

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.

Re: [MW:34105] SA266 GR4N 4 Cycle SPWHT

Hi, You are correct, Minimum refers to the one cycle for which this part will expose until final work shop PWHT. hence mill test certificate shall include this. Max. SPWHT, refers to additional cycles of heat treatment that are reserved for future repairs during equipment lifetime. Again, these simulated no. Of cycles shall be specified in MTC. The idea is we need to make sure that steel mechanical properties are not compromised upon exposure to multiple repairs (i e 4 cycles in your case). One could say, if steel is subjected to 4 cycles and is ok, then it should by defacto be good for one cycle, yet, this is wrong assumption cause mechanical problems and microstructure of materials varies accordingly based on no. Of cycles for which material will expose. This is apparent in alloy steel and especially for impact test values as an example. In your case, this forged CS with properties before PWHT can be understood to be " as forged" condition (i.e. Wit...

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

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...

Materails FAQs

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...

Materials & Welding

Search This Blog