ASTM E446-98

1.1 These references illustrate various types and degrees of discontinuities occurring in steel castings that have section thicknesses up to 2 in. (51 mm) (Note 1). They are intended to provide the following:

1.1.1 A guide enabling recognition of discontinuities and their differentiation both as to type and severity level, where applicable.

1.1.2 Example radiographic illustrations of discontinuities, that are ungraded, for reference in acceptance standards, specifications, and drawings.

1.1.3 Sets of reference radiographs from which purchasers and suppliers may, by mutual agreement, select particular illustrations to serve as standards representing minimum acceptability. At the same time, the standards so established may be unambiguously identified by alphabetic defect category (or type) designation and severity level.

Note 1-Reference radiographs previously used for this thickness range carried the designation E71, but included a now rarely used gamma source, that is, radium. The current document is also updated by inclusion of several recognized shrinkage or C categories and by elimination of the crack and hot tear categories except for one example of each of these discontinuity types. Reference radiographs for thicker sections may be found in E186 and E280.

1.2 These reference illustrations consist of three separate sets (Note 2) as follows: (1) medium voltage (nominal 250-kVp) X rays. (2) 1-MV X rays and iridium-192 radiation, and (3) 2-MV to 4-MV X rays and cobalt-60 radiation. Each set is for comparison only with radiographs produced with equivalent radiation. It should be recognized that each energy level is not applicable to the entire thickness range covered by this document. Each set consists of 6 categories of graded discontinuities in increasing severity level and 4 categories of ungraded discontinuites furnished as examples only, as follows:

1.2.1 Category A -Gas porosity; severity levels 1 through 5.

1.2.2 Category B -Sand and slag inclusions; severity levels 1 through 5.

1.2.3 Category C -Shrinkage; 4 types:

1.2.3.1 CA -Severity levels 1 through 5.

1.2.3.2 CB -Severity levels 1 through 5.

1.2.3.3 CC -Severity levels 1 through 5.

1.2.3.4 CD -Severity levels 1 through 5.

1.2.4 Category D -Crack; 1 illustration.

1.2.5 Category E -Hot tear; 1 illustration.

1.2.6 Category F -Insert; 1 illustration.

1.2.7 Category G -Mottling; 1 illustration.

Note 2-The illustrations consist of the following: Volume I: Medium Voltage ( Nominal 250 kVp ) X-Ray Reference Radiographs-Set of 34 illustrations (5 by 7 in.) in a 15 by 17-in. ring binder. Volume II: 1-MV X Rays and Iridium-192 Reference Radiographs -Set of 34 illustrations (5 by 7 in.) in a 15 by 17-in. ring binder. Volume III: 2- MV to 4- MV X Rays and Cobalt-60 Reference Radiographs -Set of 34 illustrations (5 by 7 in.) in a 15 by 17-in. ring binder. Note 3-Although Category G-Mottling is listed for all three volumes, the appearance of mottling is dependent on the level of radiation energy. Mottling appears reasonably prominent in Volume I; however, because of the higher radiation energy levels mottling may not be apparent in Volume II nor Volume III.

1.3 The use of this document is not intended to be restricted to the specific energy level or to the absolute thickness limits that are contained in the document title. The title is intended to be descriptive and not restrictive. The document may be used, where there is no other applicable document, for other energy levels or thicknesses, or both, for which it is found to be applicable and for which agreement has been reached between purchaser and manufacturer.

1.4 The values stated in inch-pound units are to be regarded as the standard.