Pre heat temperature

[shibu simon]

Dear all,

Carbon steel base metal initial temperature was 32 deg celcius, during PQR qualification as per API 1104. Decreasing pre heat temperature is an essential variable as per API 1104. So what minimum preheat temperature to give in WPS.

Thanks.

shibu simon

[pirama rayan]

Dear Shibu

 

What is thickness range of the pipe and CE value ?

 

Piramarayan B

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[AAKARSH PP]

Hi shibu,

U can give mini. 10 deg. in WPS for CS pipe, for WT upto 25.4mm. 

On Sat, Jul 17, 2010 at 9:08 PM, shibu simon <shibusi...@yahoo.co.uk> wrote:

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Regards
AAKARSH PP
QA/QC-Welding
LTCS Shop-Hyundai Engg. & Construction
Karan Gas Field Development Project

[shibu simon]

Hi priama   PQR test coupon thickness is 12.7 mm. and CE - 0.38 Regards.   shibu --- On Sun, 18/7/10, pirama rayan <piram...@gmail.com> wrote:

[AAKARSH PP]

Hi,

for CE upto 0.46 & WT  upto 12.7 mm , you can use 10deg celsius as preheat temp.

[murali krishnan]

Dear Shibu,

 

Find the attached chart for Preheat requiremets, for the below query mention preheat temperature as min 50deg c in the WPS.

 

regards,

On Sat, Jul 17, 2010 at 9:08 PM, shibu simon <shibusi...@yahoo.co.uk> wrote:

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G.Murali krishnan

[shibu simon]

Hi dear,   Minimum pre heat temperature is not mentioned in API 1104, but in sec 9 specified. Then how i can determine the minimum pre heat temperature is 10 deg. C as per API 1104. Just before starting welding, temperature was 32 deg. C. and decreasing preheat temperature is an essential variable as per API 1104. Please clarify.   shibu simon --- On Mon, 19/7/10, AAKARSH PP <aakar...@gmail.com> wrote:

[ravinder sharma]

 

 

Dear all,

 

I am looking for this material

15 NiCuMoNb 5/1.6368 (WB36)

This is the pipe used for power plants of 600 MW. I could not able to match its spec. with ASME. I require one meter spool piece of diameter more than 12’’ and thickness should be more than 40 mm for procedure qualification. I want to know following things.

 

1.      Source of material.

2.      What consumable to be used for GTAW/ SMAW/ SAW/FCAW.

3.      The parameters.

4.      PWHT heating cycle.

 

 

Regards

 

Ravinder Sharma

 

P  Please consider the environment before printing this e-mail       

 

 

 

 

 

 

 

 

 

[Raghuram Bathula]

WB36, which is a German low alloy steel (LAS). It differs from typical LAS's primarily by the presence of Cu, which causes precipitation hardening, thereby increasing the strength by about 15-20KSI (103-138MPa) compared to a typical ASME/ASTM LAS, without decreasing the ductility. 

15NiCuMoNb 5 (WB36,1.6368) is in Germany applied as PV-steel (up to 340°C) in some NPP and as pipe material (below 300°C) in many fossil power plants 

Also you may refer code case 2353 in ASME BPV for this material 

Main composition: 

0.15%C, 1.15%Ni, 0.65%Cu, 0.35%Mo, 0.02%Nb 

refer following link for info on consumables

http://www.t-put.com/english/files/welding_filler_metals_for_plant_engineering_01_2008.pdf

[jose]

Dear Ravinder,

15 NiCuMoNb 5 is mainly using in power plants feed water line having high pressure and medium temperature (near about 400 degree).

 

The chemical composition is given below

C	Mn	P	S	Si	Ni	Cr	Mo	Cu	Nb	N
0.10-0.17	0.80-1.20	0.025 max	0.020 max	0.25-0.50	1.00-1.30	0.30 max	0.25-0.50	0.50-0.80	0.015-0.045	0.020 max

 

The tensile strength is between 59 to 75 Kg / mm2

 

The composition & properties are nearly similar to P4 & P5 materials.

 

 

For GTAW  welding filler wire ER-80SG  is suitable

For SMAW  welding electrode E-10018-G  or E -9018-G  is suitable(For both PQR will be get pass) 

Regards

Jose Sebastian

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Jose Sebastian I Assistant Manager-Mechanical |
5 X 660MW Thermal Power Project I
Adani Power Limited I
Mundra  | 370435 | Gujarat | |ndia |
T +91 9687660525 | + 91-2838-266086 |
E josev.s...@adani.com | www.adanipower.com

[Ravinder Sharma]

Hi All,

 

I have welded joint of P91 of 400DN and 40 mm thickness, due to unavoidable reasons we have to do the heat-treatment after 60 days,

 

Is there requirement of ISR?

 

If yes, what should be the heating cycle?

 

Regards

Ravinder Sharma

[pgoswami]

Hi Ravinder,

 

Grade 91 demonstrates substantial harden ability when welded. Although the hardness of the base material is around 220 Hv, hardness of weld metal as fabricated prior to PWHT can reach 450 Hv. This as welded high  hardness results in substantial strength differences between the base material and the weld metal, which can lead to fatigue notches for equipment loaded by cyclic forces. Additionally, weld metal with hardness of this level generally does not exhibit adequate toughness to resist crack initiation or propagation. High hardness welds may also be susceptible to stress corrosion cracking (SCC) in humid environments.

 

The figure shown below the default recommendation for welding P-T-91 steel.  This steel is fully martensitic when welded with the below recommended cycle, and that’s required for this steel. The  major purpose of using this steel is to  lower superheater  and steam piping thickness for better heating efficiency and superior creep resistance. P-91 steel if treated like other Cr-Mo steels would spell disaster only.

 

There’s no allowable temperature for ISR of this steel in ASME Code. However I’ve come across some consulting companies specification where the recommended maximum ISR temperature is 427 ⁰ C(800⁰F), with typically 2 hrs / inch of soak at this temperature. Hardness readings require to be taken at this point to get the idea about weld and HAZ hardness. Following ISR the pipe spools shall be wrapped dry. Final PWHT shall be performed ASAP following the ISR , preferably within a week or two. Delaying the PWHT to 60 days could seriously harm the components, especially chances of failure during further fit-ups, hydro test or even later during equipment commissioning. You need to discuss this with your clients.

 

My organization is involved with EPRI (www.epri.com). In North America EPRI championed the awareness on P-91 steel amongst electric utilities and fabricators.

 

For your information this alloy was introduced in 1980’s for FAST Breeder Test reactor for US atomic Research program. However once adopted by ASME Sec-I for super critical boilers, it took a decade or more in North America to come to real terms, with respect to  understanding  the steel metallurgy and fabrication requirements.

 

In order to avoid ambiguity with other Cr-Mo steels, 2010 ASME Sec-IX changed the P No of this steel to  P-15A.

 

Hope this provides enough guidance in your endeavor. You may find the attachments as useful info.  

 

Thanks

 

Pradip Goswami,P.Eng.

Welding & Metallurgical Engineer/Specialist

Email-pgoswami@sympatico.ca,

pgos...@quickclic.net

 

·        Typical thermal cycles observed during welding and PWHT

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[John Henning]

ISR is beneficial in reducing hydrogen and thereby minimizing the potential for hydrogen assisted cracking (cold cracking).  ISR is typically performed by heating for 2 to  4 hours at temperatures between 800 and 1100 F (usually a customer requirement will apply)

 

More importantly – As Welded 91 is susceptible to stress corrosion cracking in the presence of water.  ISR may increase the potential for SCC by promoting secondary hardening.  You must provide a means to keep these welds warm and dry – no rain, no splashing, no dew formation, etc – best kept indoors in controlled environment.    Additional warning - SCC can be very difficult to detect.

 

John

 

From: material...@googlegroups.com [mailto:material...@googlegroups.com] On Behalf Of Ravinder Sharma
Sent: Wednesday, September 22, 2010 5:49 AM
To: material...@googlegroups.com
Subject: [MW:7143] ISR of P-91 pipes.

 

Hi All,

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[Vanchinath S.A.]

Dear Goswami,

P no as per latest Section IX is 15E and not 15A for P91 / T 91

vanchi

[Ravinder Sharma]

 

Can anybody suggest me cutting tool for P91 pipes. ?

 

regards

Ravinder Sharma