ASTM E570-20,Standard Practice for Flux Leakage Examination of Ferromagnetic Steel Tubular Products.ASTM E570-20 pdf free download.
ASTM E570-20 covers the application and standardization of equipment using the flux leakage test method for detection of outer surface and inner surface discontinuities in ferromagnetic steel tubular products (Note 1) of uniform cross section, such as seamless and welded tubing. While this method may be sensitive to subsurface discontinuities, it is not the primary method used to identify these types of discontinuities. A secondary method, such as Ultrasonic Testing, should be considered for assessment of these types of discontinuities.
4. Summary of Practice
4.1 This method consists of the following steps:
4. 1.1 The tube wall is magnetized at the area under examination to a proper level approaching magnetic saturation.
4.1.2 A flux sensor containing magnetic transducers is placed on or above the outside surface of the tube in the magnetized area.
4.1.3 Either the tube or the flux sensor is moved at a constant speed in the direction of the magnetic field so that the sensor scans the entire surface of the tube.
4.14 Each magnetic transducer in the fux sensor is con- nected to an electronic console which amplifies, filters, and electronically processes the signals such that significant dis continuities are indicated (visually, audibly),and marked with paint, or automatically removed from the production line, or both.
4.1.5 A suitable means for assuring near magnetic saturation of the product (subject to periodic check or calibration ) must be rovided as part of the examination to verify the capability of detection of outside diameter and inside diameter discontinuities.