UNDERCUT

DEFECT WELD

(VISUAL)

UNDERCUT

UNDERCUT

Because
1. Temperature metal too high .
2. Ampère capping high .
3. Speed capping too low

Result
1. Weaken connection.
2. Started rust the surface.
3 .Cause voltage sliding ( displacement stress ) potential to crack .

Countermeasures :
1. Enough clean up with wire brush and filling it with stringer ( welding lane single without swing according wps repair.

Rejection criteria :
1. The depth of more than 1/32 “or more than12 ½ % thick nominal material.
2. The depth of more than 1/64” to 1/32 “or more than 6% to 12 ½ % thick nominal material.
3. A length of more than 2 “ in 12 “ Welds or more than 1/6 length weld.
4. ROOT UNDER CUT more than 2” in 12 “ ROOT or more than 1/4 length ROOT .

SURFACE COLD LAP

DEFECT WELD

(VISUAL)

SURFACE COLD LAP

SURFACE COLD LAP

Because
1. Temperature metal low.
2. Capping ampère low.
3. Swing not fixed.
4. The surface of the material dirty.

Result
1. Is incomplete fusion Potentially crack.
2. Arising suspicion that all lane welds been implemented ampère low so as to lead to fusion between elementary substance with the welds or inter lane imperfect.

Countermeasures :
1. If suspicion not proved , then cold laps sufficient in grindstone with the uniform.
2. If suspicion proven and all the troubled demolished ,repair welding as WPS repair .
3. If it is still troubled,Change welder.

Rejection criteria :
The existence of surface cold laps were rejected and must be repaired.