bel valve - cladding & extra tungsten carbide deposit...

Presented byR.Baskar, AMIE (Mech)

ASNT NDT Level III RT,UT,PT & MT

CSWIP 3.2

AWS – SCWI

BEL Valve - Cladding & Extra Tungsten Carbide Deposit issue – Case Study

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• Bond integrity and volumetric

examination of Weld overlay (cladding)

• Extra material Deposit (Tungsten Carbide)

BEL Valve - Cladding & Extra Tungsten Carbide Deposit issue –Case Study



BEL Valve - Cladding & Extra Tungsten Carbide Deposit issue – Case Study

Technical Justification

follows



Bond integrity and volumetric examination of

Weld overlay (clading)

BEL Valve – Cladding issue – Case Study



Bond integrity and volumetric examination of

Weld overlay (clading)

BEL Valve – Cladding issue – Case Study

Lack of bonding at

weld fusion face



Ultrasonic Indication from overlay fusion face

BEL Valve – Cladding issue



Ultrasonic equipment REFERENCE LEVEL

(RL) set through reference block


RL Set at 90% FSH



Ultrasonic Testing - Reference block


Flat bottom Drilled Hole Reference Reflector

Weld Interface



Bond integrity and volumetric examination of weld overlay (cladding) in accordance with API 6A



Ultrasonic Testing - Acceptance Criteria


Reference : API 6A, Para. 7.4.2.3.15 - b - 2





• RL Set at 90% FSH• Rejection level for

single indication

Rejection level for multiple indication 45% FSH



Ultrasonic Testing - Acceptance Level


Rejection level for Multiple indication

Rejection level for Multiple indication

Multiple indication from 11” ball (S.No. 48122)

Multiple indication from 9” ball (S.No. 48140)

No indication




based on area


Reference : ASME / ASTM SA 265 Para. 13.3.3 and 13.3.4

Based on area it is only 0.13 – 0.14%, hence it can be ignored




Video Display – Tungsten Carbide deposit

BEL Valve – Extra material Deposit (Tungsten Carbide) issue – Case Study




During Tungsten carbide coating at outer surface, by process error ROBO equipment

deposit some portion with Tungsten Carbide into inner surface area of bore. Deposit uptomax. 3mm.


Extra material Deposit

(Tungsten Carbide)



This Extra material deposit confirmed following checking:

• Visual inspection, by surface color difference between Tungsten Carbide coating and cladding material deposit area

• During dye penetrant testing noticed red color contrast at Tungsten Carbide area. Which is probably due to porous material observed penetrant and resulting red color contrast at that location.

• Checked with PMI and noticed 80 – 84 % of Tungsten, other location 55 – 60 % Nickel

• Checked hardness test and noticed 50 – 55 HRC, other cladded area 32 – 35 HRC

• Checked with coating thickness gauge, it noticed 1 to 3 mm coating thickness

• Inner diameter measured and noticed reduced dimension, than the nominal bore dimension.

• General information, this extra material deposit is very smooth transition and stress raise free.

Based on the above check, it is clearly shows Tungsten Carbide deposit




Table shows Tungsten Carbide Details




Suggested Conclusion for Cladding

Based on the review of Ultrasonic indication evaluations, the

indication in the cladding are well within acceptable limit and it will

not affect the integrity of the valves. The valves are fit for purpose.

Leave indication in the cladding as is.

bel valve - cladding & extra tungsten carbide deposit...

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