ROOT POROSITY

DEFECT WELD

NON VISUAL

ROOT POROSITY

Root Porosity

Because :
1. The condition of the root damp or moist.
2. Electrode moist
3. Purging gas contaminated ( GTAW )
4. No purging gas ( GTAW )

Result :
1. Weaken Connection weld.
2. Started erosion abrasion.
3. Started INTERNAL CORROSION.

Countermeasures :
1. Gouging until roots in the location of a defect in the welds and appropriate contents WPS REPAIR.

Rejected Criteria
1. INDIVIDUAL more than 1/8 “ or 25 % minimum thick .
2. The distribution of goods more than the stipulated API 1104 picture 15 and 16.
3. For Cluster Porosity diameter more than 1/2 “ , total length porosity 12 “ Welding more than 1/2 “

INCOMPLETE PENETRATION (IP)

DEFECT WELD

NON VISUAL

INCOMPLETE PENETRATION

INCOMPLETE PENETRATION

Because :
1. GAP too narrow
2. Ampere root low
3. Welding machine not Calibration
4. The electrodes up and down
5. GAP dirty

Result :
1. Notch potential crack.
2. weaken weld joint.
3. Started erosion abrasion.

Countermeasures :
1. Gouging until roots in the location of a defect in the welds and appropriate contents WPS REPAIR.

Rejected Criteria

• API 1104 : 1. INDIVIDUAL > 1 “ , 2. Total length 12 “ welding > 1 “ , total length of weld 12 “ length weld > 8% length weld.
• If IP potential HIGH LOW : 1If side of the root of open > 2” ( INDIVIDUAL ) , 2. In 12” length weld , total length > 3” .

Accepted Criteria

• ANSI B 31.3 : 1. INDIVIDUAL ≤ 1 mm ( 1/32 “ ) and ≤ 0.2 X weld thicknes normal . 2. Total length of weld 6 “ ≤ 38 mm ( 1 ½ “ )

EXCESS WIRE

DEFECT WELD 

NON VISUAL 

EXCESS WIRE 

EXCESS WIRE 

Because :
1. WELDING WIRE COROTION
2. WIRE FEEDER NOT NORMAL .
3. Electricity supply disconnected breaking up

Result :
1. NOTCH POTENTIAL CRACK.
2. DAMAGE CLEANING PIG

Countermeasures :
1. Gouging until roots in the location of a defect in the welds and appropriate contents WPS REPAIR.

Rejected Criteria  :
Rejected its existence

ROOT UNDERFILL

DEFECT WELD

NON VISUAL

ROOT UNDERFILL

ROOT UNDERFILL

Because :
1. Gap dirty..
2. Ampere root low.
3. Temp metal cold.
4. HIGH LOW.

Result :
1. Notch potential crack.
2. Damage cleaning pig.

Countermeasures :
1. Gouging until roots in the location of a defect in the welds and appropriate contents WPS repair.

Rejected Criteria
API 1104 : If the number of a length of more than 2 “ in 12” Long welds or the length of more than ¼ long welds overall, Reject .

Accepted Criteria
ANSI B31.3 : for normal category , SEVERE CYCLIC and category D , LONGITUDINAL GOOVE don’t have UNDERCUT , for branch connection ≤ 1 mm ( 1/32 “ ) and ≤ ¼ thick normal weld.