ROOT CONCAVITY

DEFECT WELD

NON VISUAL

ROOT CONCAVITY

ROOT CONCAVITY

Because :
1. Gap too wide
2. SPEED ROOT too high .
3. AMPERE ROOT high
4. ELEKTRODA too big.
5. For STAINLESS STEEL ROOT GTAW In override in topped with GTAW So that root melted again and sucked up by the process of caping.


Result
1. Started erosion abrasion.
2. S.C.C ( CL2 , NaOH ).
3. weaken weld join .


Countermeasures :
1. GOUGING until the root , setting again and repair welding as WPS Repair.



Rejected Criteria
API 1104 :
1) IF INDIVIDUAL > ¼ INCI,
2) SEPANJANG TEBAL PIPA ,
3) all length welding 12” > ½ “ .



ANSI B 31.3 : The depth of root concavity acceptable when the number of connection plus welding reinforcement > thick nominal ( T W ) b). in 12” length weld > 3inch

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HIGH LOW

DEFECT WELD

(VISUAL) 

HIGH LOW

High Low

Because :
1. Any setting
2. Different thick

Result :
1. Started erosion abrasion.
2. Producing a voltage sliding potential to crack

Countermeasures :
1. The prominent part in an oblique 1 : 3 ( ASME VIII ) 1 ; 2.5 ( ANSI B31.3 )

Rejected Criteria
1 ANSI B31.3 : t ≤ ¼ “ max. 1.5 mm ( 1/16 “ ) EXTERNAL t > ¼ ~ ≤ 13 mm ( ½ “ ) , max. 3 mm ( 1/8” )t > 13 mm ( ½ “ ) ~ ≤ 25 mm ( 1” ) ,max 4 mm ( 5/32 “ ) t > 25 mm ( 1 “ ) , max 5 mm ( 3/16 “ )
INTERNAL = 2 X EXTERNAL exceeds the maximum mentioned above, if no do it, rejected

2. API 1104 :

a). If any side of weld opened >2inch individual.
b). in 12” length weld > 3inch

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STOP START

DEFECT WELD

(VISUAL)

STOP START

stop start

Because :

• Bulge recurring caused by replacement electrodes too backward so there overlapping prominent.
• The empty without capping in a recurrent manner caused by the replacement of electrodes too forward.

Result
1. THE STANDOUT LOOKS BAD AND INEFFICIENT
2. That empty inflict NOTCH Potentially crack.

Countermeasures :
1. Prominent grinding sufficient in to the standard
2. Thr empty grinding must be to rest of slag missing , then welds rearranged wps repair

Rejection criteria :
1 .To prominent recurring acceptable on the condition in burrs to the form of standard.

2 .To empty acceptable origin repaired by filling capping to the form of a welds uniform .If this mentioned above not carried out , the welds rejected

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