ASTM A333 GR.6 high haz and NACE Required ( 248 HV - 22HRC )

[Paolo.I]

Dear All,
I need help
we performed a butt weld ( full penetration ) qualification with the following characteristics:

ASTM A350-LF2 to ASTM A333 GR.6
Thickness of pipe 5,54 [mm]
Diameter of Test Coupon 60,30 [mm]( 2 inc )
Welding Process(es) GTAW
Poition 6G
Amps. 100 to 130
Volts 15 to 16
Max. Heat input (J/mm) 2635
MIN. Heat input (J/mm) 1742
Wire SFA Specification ER 70S-3 ( size 2.4mm)
Preheat Temperature (MIN.) [°C] 20
Interpass Temperature (MAX.) [°C] 230
NO PWHT

as per object I obtained high hardnesses in the HAZ ( 270 - 283 HV ) on ASTM A333 GR.6 SIDE, the basic material is in accordance with NACE (<22HRC )

Do you have any suggestions for lowering the hardness? example :

Wire SFA Specification, higher preheats,ex...


I Didn't PHWT in production.

Thanks to anyone who helps me.

 

[weldstan]

Increase preheat and if you can under your WPS/PQR, incease interpass temp. You can also wrap weld with insulation after weld completion. This all assumes that your hardness readings are actually accurate.

 

[r6155]

Check hardness before welding.

Regards

 

[SJones]

What is the carbon equivalent value of the pipe.

Steve Jones
Corrosion Management Consultant

http://www.linkedin.com/in/drstevejones

All answers are personal opinions only and are in no way connected with any employer.

 

[Paolo.I]

@weldstan
I agree with you, i think that need to improve the preheat and heat imput

@r6155
The hardnees of the report on base material meet the naece requrement, more precisely, the maximum value found is 240 HV

@Sjones
Carbon Equivalent [CEQ] 0,41
Carbon Contenet 0,19


thanks to ALL

 

[weldstan]

Actual hHardness of 240HVN max and carbon content are really abnormal for A333 gr6. At least it was 8+ years ago before my retirement.

 

[SJones]

A number of contractors demand that the client impose a 230 HV maximum on parent materials so that they have a fighting chance of keeping within 248 HV when they weld. For the grade of pipe, the chemistry, and the dimensions, something just doesn’t seem right about 240 HV.

Steve Jones
Corrosion Management Consultant

http://www.linkedin.com/in/drstevejones

All answers are personal opinions only and are in no way connected with any employer.