Which is first and far-most important (Non-Destructive Technique)NDT Technique?

Radiographic test, beacuse It find almost all defects with proper location .

techniques of direction

it's the X-Ray which discovered by Wilhelm Rontgen in1895.

It's visual testing technique(VT) It's first NDT technique and also it's very cheep n using very commonly in industry...!

Dye Penetrant Testing (DPT)

should be select the suitable ndt  method of joints,that means surface ndt or volumatric ndt  and this  reguirments must  copmly with codes and std.

 

the X-ray test that is the most applicable method in the industry

I think it is the sonic technique used by blacksmiths. 

no, it is not X-Ray.. think more & read my question again

GTP

visual testing