T.O. 33B-1-1Figure 1-14.Use of IIW Block to Check Entry Surface Resolution1.8.2.4.3Checking Entry Surface Resolution with ASTM Blocks.a.Use an ASTM block with a #5 FBH, or other size if specified. Choose a block with a metal traveldistance according to the frequency being used (see Table 1-8).b.Maximize the separation between the initial pulse and the hole signal.c.Check that the hole signal is actually the indication of the first echo from the hole by noting theposition of the hole signal on the calibrated distance scale of the waveform display. The distanceshould be the actual depth of the hole.d.Evaluate the waveform patterns.1.8.2.5DistanceCalibrationofAScan.1.8.2.5.1Straight Beam Distance Calibration for Weld Inspection (IIW Block).a.Position the search unit on an IIW block at P-1, P-2 or P-3 as shown in Figure 1-15. This distancebetween multiple back ref lections is as follows:(1)1.00 inch at P-1(2)4.00 inch at P-2(3)8.00 inch at P-31-62Change 2
Integrated Publishing, Inc. - A (SDVOSB) Service Disabled Veteran Owned Small Business