Ultrasonic Testing AS1710

Ultrasonic testing of plate is carried out for various engineering applications to ensure the product is free of any injurious defects.

This standard applies to the testing of steel plate for general internal quality, using methods, which specify scanning to a designated scanning system. Quality grading, allows the specification of three quality levels for the body of the plate and one quality level for the edge zone (Levels 1, 2, 3 & E).

BlueScope Steel would normally limit the maximum thickness for Level 1 and 1E to 110mm and levels 2, 2E, 3 and 3E to 150mm for ultrasonic testing of plates. Plate thicknesses above these values should be referred to customer technical services.

Scanning of Plate

Level 1 - Scan transverse to rolling direction at intervals of 75mm centres over the entire plate.

Level 2 - Scan transverse to rolling direction at intervals of 100mm centres over the entire plate.

Level 3 - Scan transverse to rolling direction at intervals of 150mm centres over the entire plate.

Plate Edges

Trimmed edges (sheared, slit or gas cut)

For all quality levels, scanning along the plate edges shall be in a continuous band within 25mm of the trimmed edges.

Untrimmed edges (universal or mill edge)

Where plates are ordered with untrimmed edges (universal or mill edge), supplementary edge scanning may still be carried out. The first 25mm from the untrimmed edge or half the plate thickness up to a maximum of 50mm would not be certified. The next 25mm would be tested as per normal edge testing requirements.

Evaluation Sensitivity

For plate thicknesses > 5mm and < 15mm

The gain required to bring the first back echo to full graticule height.

For plate thicknesses > 15mm and < 40mm

The gain required to bring the second back echo to full graticule height.

For plate thicknesses > 40mm and < 180mm

The gain required to bring the first back echo to full graticule height.

Sensitivity shall be monitored continuously. Any change in testing conditions shall be immediately compensated for by adjusting the gain of the flaw detector to maintain the correct testing sensitivity.

Evaluation

For plate thicknesses
> 5mm and < 15mm - Twin 4 MHz
> 15mm and < 40mm - Single 4 MHz
> 40mm and < 180mm - Single 2 MHz

Probes and sensitivities used for plate testing differ from those used in weld testing. Therefore different results can be obtained testing the same material.

Significant Discontinuity

Any indication greater than 50% of the reduced first or second back echo is considered significant. When significant discontinuities are found evaluation probes and sensitivities are used.

Evaluation

For plate thicknesses > 5mm and < 15mm

Laminations - Any discontinuity causing total reflection of acoustic energy for a probe movement of 5mm in a direction transverse to the major dimension of the discontinuity.

Cluster - Each area over which the echo amplitude exceeds 50% of the first back echo or reduced back echo. This determination shall be made when the discontinuity echo and the back echo are displayed simultaneously.

For plate thicknesses > 15mm and < 40mm

Laminations - Any discontinuity causing total reflection of acoustic energy for a probe movement of 5mm in a direction transverse to the major dimension of the discontinuity.

Cluster - Each area over which the echo amplitude exceeds 50% of the second back echo or reduced back echo. This determination shall be made when the discontinuity echo and the back echo are displayed simultaneously.

For plate thicknesses > 40mm and < 180mm

Laminations - Any discontinuity causing total reflection of acoustic energy for a probe movement of 5mm in a direction transverse to the major dimension of the discontinuity.

Maximum Size of Discontinuities: Main Body of Plate

Quality Level	Minimum area discontinuity considered (significant discontinuity mm²)		Maximum area of any individual laminar discontinuity	Maximum total area of discontinuity in any area 1m x 1m mm²		Maximum avg. inclusion cluster area per m² of entire plate surface
Quality Level	Lam.	Incl.	mm²	Lam.	Incl.	mm²
Level 1	500	2,000	1,000	3,000	5,000	1,500
Level 2	500	2,000	3,000	10,000	16,000	6,000
Level 3	1,000	5,000	6,000	20,000	40,000	15,000

Maximum Size of Discontinuities: Plate Edges (trimmed edges only)

Quality Level	Min area of discontinuity considered significant discontinuity	Maximum length of discontinuity	Maximum area of individual discontinuity	Maximum avg. length of discontinuity in any 1m length	Maximum length of discontinuity per metre of edge length
Quality Level	mm²	mm	mm²	mm	mm
Level E	300	50	500	100	50