NDT TRAINING COURSE IN CHENNAI
DEFECTOLOGY
Welding
Plate
Casting
Forging
n Processing Discontinuities
Service Discontinuities
WELDING
Crack
Lack of Penetration
Excess Penetration
Lack of Fusion
Under Cut
Mismatch
Porosity
Slag
Spatter
Cause for Crack
Improper Temperature
Improper Travelling Speed
Improper Selection of rod
Cause for Lack of Penetration
Improper root gap
Improper welding rod Selection
Cause for Excess Penetration
Improper Technique
Improper Travelling Speed
Improper rod diameter selection
Insufficient Current Input
Cause for Lack of Fusion
Insufficient heat input
Improper joint Design
Improper Weld Technique
Cause for Under Cut
Voltage and welding current too high
Wrong Gun Angle
Insufficient Dwell time
Cause for Mismatch
Misalignment of the job
Improper joint Design
CAUSE FOR POROSITY
Caused by exposure of molten metal to O2, N, H in the atmosphere
Presence of foreign matter, water, humidity, oil, grease,etc.
CAUSE FOR SLAG
Poor interpass Cleaning can cause
slag inclusion
CAUSE FOR SPATTER
Does not affect weld strength but dose
produces a poor appearance and increases cleaning cost.
Plate
Lamination
Inclusion