Re: [MW:33343] Hardness Issue on weld metal

Dear Sir,

Thanks for your email.

Consider my reply marked in "Blue"

On Thu, Jul 28, 2022 at 7:25 AM Sudhakar Kuppuswamy <sudhakarceng@gmail.com> wrote:

Hi, 

With 600 Deg C as holding temp and one hour holding time is not adequate to bring down the hardness . Increasing  the holding time to 2 hours minimum will definitely help. 

Otherwise , holding temp of about 650 Deg C will greatly help in reducing the hardness. - This material tempering done at 630°C

    That's why we decided to conduct the PWHT at 600 °C (lower than the tempering temp.)

To have a good control on the cap side hardness (I.e the  last layer hardness) please try to slightly increase the pre-heat temp to the maximum possible extent. let say, in your case above 220 degrees C but less than 260 degree C. Also deposit the cap pass with temper bead technique. By doing so, the layer underneath the cap pass gets well annealed, so the hardness limit will fall within the acceptable limits. - We will start doing this method  

Hope this helps!

Regards,

Sudhakar K 

On Wed, 13 Jul 2022 at 3:22 PM williams p wilson <williamswilsonp@gmail.com> wrote:

Dear Experts,

During the PQR qualification of ASTM A 519, Grade 4130 , Pipe 3" x Sch XXS material hardness value in SMAW weld metal area observed in b/w 247 to 283 HV.

The required value is in blw 201 to 241 HV, Base metal hardness also is in the same range.

Preheat temperature : 200 ° C

Interpass temperature : 300 ° C (Max)

Stress relieving details as follows,

600 ° C ± 10  ° C, Holding Time : 01 Hour

Cooling Rate : 150 ° C / Hour
Heating rate : 150 ° C / Hour
Unrestricted heating up to 300 ° C
Controlled cooling upto to 300 ° C

Please reply with your valuable comments to reduce the high hardness observed in the weld metal.

Thank You & Regards

Williams P Wilson

QA/QC Engineer

Welding Inspector (CSWIP 3.1)

Cell: (+968) 94600828

P Please consider the environment before printing this message

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Regards,

Sudhakar K CEng MWeldI,IWE.

Welding & Metallurgical Engineer,

Email: sudhakarceng@gmail.com.

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