Skip to main content

Re: [MW:25218] RE: 25208] Reg. post heating for low alloy steels

By Materials & Welding
Correct me if I am wrong nut martensitic transformation occurs in the range of 800 to 400 degC

2016-08-07 6:41 GMT+03:00 pgoswami <pgoswami@quickclic.net>:

What're thickness involved. You've to respect the materials engineering requirements, otherwise pay the price. For example  it's not advisable  to weld P-91 steel without any provision for immediate PWHT. Better try when you're ready with PWHT facilities.

 

You may delay PWHT for the other grade by adopting Post Heating or DHT, but may not have much luck with Garde-91 steel.

 

For P-91 a DHT @ 300-350 Deg C / 4 hrs is recommended as an alternative. Mind you NON-heat treated hardness of grade-91 steel would be easily over 350 HV, hence any impact loading, rough handling could crack the welds. Hence sooner the PWHT done, it's better.

 

Also note DHT for grade -91 steel must be done after cooling the steel to room temperature for the whole martensitic transformation to occur. DHT should follow next. Without this the creep properties would be bad.

 

It's better to know the full details first.

 

Shell DEP's are exhaustive , read thoroughly & you'll have the answer.

 

 

Thanks.

 

Pradip Goswami, P.Eng,IWE
Independent Welding & Metallurgical Engineering Specialist ,

Ontario,Canada.
ca.linkedin.com/pub/pradip-goswami/5/985/299

pgoswami@quickclic.net

pradip.goswami@gmail.com

 

From: materials-welding@googlegroups.com [mailto:materials-welding@googlegroups.com] On Behalf Of Prasu Cutie
Sent: Saturday, August 06, 2016 10:33 PM
To: materials-welding@googlegroups.com
Subject: [MW:25208] Reg. post heating for low alloy steels

 

Dear experts,
We are going to start pqr for low alloy steels i.e. A335 Gr P11, P22, P5, P91 etc, it suppose to be post weld heat treated immediately  after welding. As per literature if pwht is not possible immediately  after welding, intermediate PWHT recommende .i.e pos heating.
Now the question is is there any code reference for the same? What is the heating time n temp???
The codes we r following  here are shell dep's n asme b 31.3
Project: refinery

Awaiting for your reply

Thanks n regards
Prasad
0096594122634

--
http://www.linkedin.com/groups/MaterialsWelding-122787?home=&gid=122787&trk=anet_ug_hm
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.
---
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.
To view this discussion on the web visit https://groups.google.com/d/msgid/materials-welding/CAKgcArQMULX%3DQgcoXb8CgGM%3DmHiLQZG50iXgWuCR146W_HjO_g%40mail.gmail.com.
For more options, visit https://groups.google.com/d/optout.

--
http://www.linkedin.com/groups/MaterialsWelding-122787?home=&gid=122787&trk=anet_ug_hm
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.
---
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.
To view this discussion on the web visit https://groups.google.com/d/msgid/materials-welding/!%26!AAAAAAAAAAAYAAAAAAAAAOT5XfyRhstKvyeqQRSrfFXCgAAAEAAAAERVFSdS96lDmj52mtEsPMgBAAAAAA%3D%3D%40quickclic.net.
For more options, visit https://groups.google.com/d/optout.



--
Dr. Georgios Dilintas,
Dipl. Ing. In Aeronautic and Space Engineering
Ph.D in Mechanics of Solids - Computational Mechanics
A.I.S, A.N.I, IRCA Lead Auditor
Welding, Stress Analysis, Corrosion, QA/QC, Failure Analysis, Risk Analysis

--
http://www.linkedin.com/groups/MaterialsWelding-122787?home=&gid=122787&trk=anet_ug_hm
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.
---
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.
To view this discussion on the web visit https://groups.google.com/d/msgid/materials-welding/CAPOi40BH-_3_0Z%2Boc9948pTkW1kZxSTh4kNs-fGCVuz3g%2BNxWg%40mail.gmail.com.
For more options, visit https://groups.google.com/d/optout.

Comments

Post a Comment

Popular posts from this blog

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

By Materials & Welding
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...
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

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