Ultrasonic flaw detector for weld flaw, Classification of weld inspection

Ultrasonic flaw detector for weld flaw, Classification of weld inspection 

A Class

The ultrasonic flaw detector detecting flaw of welds, one angle probe can be used to inspect one individual surface (the left or right side of the front surface), only the weld cross-section allowed to be scanned need test. Generally, it is not required to do transverse defects. When the thickness of the base metal is greater than 50mm, Class A inspection shall not be used.

B Class

The ultrasonic flaw detector detecting flaw of welds, in principle, one angle probe is used for inspection 2 individual surfaces for the entire weld cross-section. (right and left on the front surface)

When the thickness of base metal is greater than 100mm, 4 individual surfaces shall be detected. (right and left on front and back surface)

Restricted by geometric conditions, using two angle probes to detect same side of the front and back surface Horizontal defects should be inspected when conditions permit.

C Class

The ultrasonic flaw detector detecting flaw of welds, at least two angle probes shall be used to inspect both side of the weld (both 2 individual surfaces on the front surface), at the same time, two scanning directions and two probe angles shall be used for transverse defect inspection. 

When the thickness of the base metal is greater than 100mm, 4 individual surface is required to be detected. 

Other additional requirements are:

- The excess height of the butt weld should be smooth so that the probe can be scanned parallel on the weld

-  On both sides of the weld, the base metal part inspected by the angle probe shall be inspected by the straight probe.

-  lf the thickness of the base material of weld is greater than or equal to 100mm, or the base material of narrow gap is greater than or equal to 40mm, in general, should add serial scanning.