| 摘要 |
PURPOSE:To prevent propagation of bond exfoliation cracking when the cracking generates in a clad part of a pressure vessel used at high temp. and under high pressure by providing a vent hole to a base material side of the clad material which has caused the bond exfoliation cracking. CONSTITUTION:An exfoliation crack 3 generates along a bond part of a clad steel and propagates. Accordingly, it is in parallel to the main strain L of the structure in the initial stage, there is no adverse influence insofar as the crack does not grow too large or in the direction of the thickness of the plate. Therefore, the propagation of the crack can be interrupted by preventing trapping of hydrogen by venting hydrogen intruded from the laminated material side 2 by providing a hole 4 from the base material 1 side corresponding to the cracked position at the time when the generation of crack is found. Since the vent hole 4 is sufficiently effective even if the dia. is so small as ca. 5mm.phi, there is no influence on the strength of the base material 1. |
