 |
|||
|
|
|||
|
|
|||
| ||||||||||
|
|  MIL-DTL-60426B(AR)
W/AMENDMENT 1
4.4 Testing. Testing is described in the Conformance Inspection Tables and the
following:
4.4.1 Radiographic examination for explosive loading defects (see 3.6). The test shall be
performed as specified in 4.4.1.1. Cavitation defects are classified as follows:
Critical: Any explosive loading defect within one inch of the top of the base plug (see 3.6.1,
3.6.3, and 3.6.4).
Major: Any explosive loading defect more than one inch from the top of the base plug (see 3.6.2
and 3.6.3).
4.4.1.1 Determination of cavitation. Radiographic equipment, operations and procedures
shall be qualified in accordance ASTM E 1742. The sensitivity of the radiographic technique
shall be 2.0 percent and the minimum photographic density of the film used shall be no less than
1.50 at every point within the projected area of explosive. The radiographic beam shall be
located in a plane which is perpendicular to the longitudinal axis of the burster and tangent to the
base. The outline of the explosive fill shall be clearly defined at all points. Examination of the
radiograph shall be made to determine compliance with applicable requirements. No images of
lead masks, containers, fixtures, identifying marks, or other extraneous features should project
into the region of explosive under inspection, with the exception of specified Image Quality
Indicators. Such screening should be free of any radiographically observable features in the
projected area under inspection. The maximum density shall be no greater than required to
permit adequate inspection over the entire area of interest. All defect-like features in the area of
interest on a radiographic image shall be treated as defects unless identified as extraneous
artifacts, in which case the burster shall be x-rayed again. All additional radiographs taken for
defect conditions shall be identified on the film as retakes and stored in a manner which is
traceable to the original radiograph.
4.4.1.2 Check of sensitivity of radiographic technique. The sensitivity of radiographic
technique shall be determined by means of Image Quality Indicators (IQI's) fabricated as
specified herein. When radiographing a number of similar bursters the frequency of the
sensitivity check shall be no less than one in each fifty radiographs, and on a rotating ring, the
Image Quality Indicators shall be used at one station for each complete rotation of the ring. The
sensitivity of the radiographic technique shall be considered satisfactory when the image of the
Image Quality Indicators, including the 2T holes, are perceptible in accordance with ASTM E
1742. The Image Quality Indicators shall be made of steel having an approximate specific
gravity of 7.8. For further details on construction of the Image Quality Indicators see ASTM E
1742.
4.4.1.3 Check of photographic density of film. The photographic density of the film shall
be determined on the film in the region of minimum film density within the projected area of the
explosive charge. Film density shall be checked each hour of operation or fraction thereof, for
each film processor. Greater frequency shall be required for any period during which difficulty
is encountered in establishing the required densities. Photographic densities shall be measured
with a diffuse density, photoelectric densitometer providing direct display of numerical density
15
|
|
Privacy Statement - Press Release - Copyright Information. - Contact Us |
Click
here for thousands of PDF manuals