Ultrasonic testing technology level selection and quality assessment

Ultrasonic testing technology level selection
The ultrasonic testing technology grade is divided into three detection levels: A, B, and C. Class A is the lowest level, low sensitivity; Class B is medium sensitivity; Class C is the highest level, high sensitivity.Ultrasonic testing technology grade selection should be based on the relevant standards and design drawings of Furukawa manufacturing, installation, and in use. The ultrasonic testing technology level of pressure pipe welded joints generally chooses Class B.

Quality rating

Weld joint quality rating(mm)

Grade

Plate thickness T

Reflected wave amplitude

Single defect indication length L

 

I

≥8

I

Non-cracking defect

8~40

II

≤10

>40

≤T/4,No more than 20

II

8~40

II

≤15

>40

≤T/3,No more than 27

III

≥8

II

More than Level II

III

All defects

I,II,III

Hazardous defects such as cracks
Note: For welded joints with different thicknesses, take the thickness of the sheet side.

Circumferential welded joint quality rating

Weld joint grade

Weld joint internal defect

Welded joint roots are not welded through defects

Reflected wave amplitude

Single defect indication length L

Defect indication length，mm

Cumulative length of defects，mm

I

I

Non-cracking defect

L=T/3，Minimum is 5

The length is less than or equal to 10% of the circumference of the weld and less than 30

II

≤10

≤T/4

II

II

≤15

L=2T/3，Minimum is 6

The length is less than or equal to 15% of the circumference of the weld and less than 40

≤T/3

III

II

More than Level II

More than Level II

More than Level II

III

All defects

I,II,III

Hazardous defects such as cracks

Note: In the range of 10mm weld, when there are strip defects and no penetration, it should be rated as Class III.

(1)For welded joints with different thicknesses, take the thickness of the sheet side.

(2)When the cumulative length of the defect is less than the length of the single defect indication, the length of the single defect indication is taken as the standard.
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