ASTM A 435 Standard Specification Straight-Beam Ultrasonic Examination of Steel Plates

Scope:

This test method was developed to ensure the delivery of steel plates is free from gross internal discontinuities such as pipe, ruptures, or laminations. Also, this test specification can be used to inquire, contract, order, or specification states that the plates are to be subjected to ultrasonic examination. 

Test procedure:

In this test method, the ultrasonic examination is made on either side of the plates. The plates ordered in quenched and tempered condition were tested following heat treatment. The test frequency is depending upon the thickness, grain size and microstructure of the material however the frequency of 2.25 MHz is used. The examination is carried out with test frequency and instrument adjustment in such a way that it produced a minimum of 50 to a maximum of 75 % of full-scale reference back reflection from the opposite side of a sound area of the plate. A suitable coupling such as water, soluble oil, or glycerin, was used. Scanning lines were measured from the center or one corner of the plate. An additional path was scanned within 2 inches of all edges of the plate on the scanning surface. The true boundaries are defined by two methods, first is to move the transducer away from the center of the discontinuity until the heights of the back reflection and discontinuity indications are equal. Then Marked the plate at a point equivalent to the center of the transducer. Repeated the operation to establish the boundary.

Video 01: Ultrasonic Plate Inspection

Test Specimen:

In this method, Steel plates were used and a specimen and 1-to-1.125-inch diameter or 1-inch square diameter transducer is used.

Data:

Any discontinuity indicator that results in a complete loss of back reflection and cannot be contained within a circle that is 3 inches in diameter or half as thick as the plate is unacceptable.

Conclusion:  

ASTM A 435 gives detailed information regarding the straight beam ultrasonic examination of steel plates. It tells us the method to examine internal discontinuities in steel plates.