Non Destructive Testing used to find defects in weld joints



How to find defects in Welded Joints and why Non Destructive Testing ?

Welding is a process of joining two metals which are similar in metallurgical properties, welding utilizes heat to join metals, the heat can applied to the base metals by various processes , few of them are electric arc, friction , electric resistance & gas flame.
The weld joints tend to have defects due to various reasons, few of them are as follows
Welder skills,
  •  Excess Current/  Low current,
  • Moisture content in metal or filler wire
  • Windy environment
  •   Less inert gas flow
  • Over speed or low speed welding
  •  Excess heating or improper cooling rates and Much more…..

There are various possible Weld defects, few are as follows
                Undercut, Under fill, Improper weld bead, Cracks, HAZ Cracks, Porosity, Cluster/Aligned Porosity,  Lack of Penetration, Lack of Fusion, Excess Penetration, Slag Inclusion. Craters, Crater Pipe, Star Cracks, Arc Strike, Spatters, Poor-Restart, Root Concavity/ Suck Back, Burn Through, Overlap &  Unfill Areas
All the defects are not visible to bare eyes and cannot be detected during Visual Testing (VT), the internal defects and not visible surface defects can be identified only by special techniques called Non Destructive Testing (NDT), there are several methods of NDT and few of them are as follows
1)      Ultrasonic Testing (UT)
2)      Eddy Current Testing (ET)
3)      Liquid Penetrant Testing (PT)
4)      Magnetic Particle Testing (MPI)
5)      Radiography Testing (RT)
6)      Visual Testing (VT)
7)      Microwave Testing
8)      Laser Testing (LT)
9)      Acoustic Testing (AT)
10)   Leak Testing and much more
The suitable NDT Method for the job is based on various parameters such as 1) Base Material 2) Type of defect to be found , 3) Thickness of the material, 4) Surface Profile, 5) Accessibility & 6) Sensitivity
To know more about your suitable NDT method for the specific jobs visit https://www.aqcinspection.com and feel free to write to us or call us. We are the best NDT training institute in Coimbatore.  We will be delighted in details explanation and assisting you towards the right methods to achieve a greater quality product.

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