Up to now many countries in the world have different pressure vessel regulations, different standards and different certification practices to assure that pressure vessels are safe. In order to remove these technical barriers to trade and permit the free movement of goods, new pressure vessel systems are in course of development in both the European Union (EU) and the American Society of Mechanical Engineers (ASME). It is code strategy of pressure vessels between EU and ASME. In this paper, Japanese code strategy of pressure vessels is briefly discussed.

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Explosively bonded composites were prepared, of commercial pure titanium to two kinds of very low carbon steel (0.005mass%C and 0.03mass%C). A microstructure of the bonded interface zone was investigated by a transmission electron microscopy (TEM) and an energy dispersive X-ray spectrometer (EDX), and reaction products in this zone were identified by selected area electron diffraction patterns. Both of as-bonded and heat-treated specimens were used. As a result, in the as- bonded specimens an amorphous bonded interface zone was formed, whose width was in range of 0.05μm to 0.2μm. In same zone, however, intermetallic compounds such as FeTi, Fe₂Ti and TiC, were not observed. On the other hand, in the bonded zone of heat-treated specimens, intermetallic compounds of FeTi and Fe₂Ti were identified by EDX analysis, where the FeTi phase, however, was found to be amorphous-like phase from TEM observation. The TiC phase was observed at the specimen heat-treated at 850°C for 20h.

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Creep rupture Strength and microstructure were investigated for base metals and simulated HAZ specimens of 9Cr-Mo or 9Cr-W steels with V and Nb.
Results obtained were as followed.
(1) The 1000°C HAZ Specimens show minimum creep rupture strength.
(2) Decrease in rupture strength in the 1000°C HAZ depends mainly on combined effect of grain refinement and coagulated carbides for 9Cr-1 Mo type steels.
(3) Substitution of W for Mo is very effective in enhancement of creep rupture strength of HAZ.
(4) Weakening of the HAZ is reduced by increase in amount of carbides during aging and higher stability of carbide with higer W content for 9Cr-2W type steels.

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The failure assessment diagram was constructed to assess the structural integrity of high-pressure autofrettaged vessels with a semi-elliptical axial defect, and a systematic sensitivity analysis of factors influencing unstable fracture under the residual stress field was performed. Under the maximum service pressure, increase in the autofrettage radius has a beneficial effect on critical flaw size ac, although it has little effect on the yielding scale at unstable fracture. Increase in the fracture toughness has a beneficial effect on both factors. When the inner-to-outer radius ratio is constant, increase in the vessel dimensions has a similar effect as decreasing the fracture toughness. When the inner radius and the safety factor of the pressure concerning plastic collapse failure are constant, the relative size of and the yielding scale at unstable fracture decrease with increasing wall thickness. In every case analyzed, the concept of leak before break (LBB) does not hold. However, the structural integrity is assured because the critical defect size is large enough to be easily detected during in service inspection.

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In this paper, the brittle fracture strength of screw joint specimens was investigated experimentally. As a result, the effects of length of thread engagement, number of free thead and initial tightening torque on the brittle fracture strength of screw joint were made clear. The brittle fracture strength of circumferentially notched round bar was also investigated.
It was found that the brittle fracture strength of screw joint was nearly equal to that of circumferentially notched round bar, in the case where diameter, notch depth and notch acuity of both specimens were the same.

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An Automatic detection method of fluorescent-magnetic particle indications for steel billets and welds using the high sensitive CCD camera and image processing techniques has been studied based on a personal computer. In this paper, the automatic detection system consists of two main processes, the extraction of flaw indications and their quantitatively sizing. The flaw indications in the billets and welds are first extracted from digitized images by means of the smoothing, the line segment extraction with the oriented templates and then the component labeling algorithms. As a result of application of these image processing techniques to detection of flaws, the effect of background noise and unwanted indications has been reduced and besides the image quality of desired flaw indications has been enhanced.
For the extracted indications of fatigue cracks with various depths in weld, the relationship between the crack depth and the degree of brightness of the corresponding indication has been experimentally investigated, and the results show that there is possibility to evaluate roughly the size of cracks by the brightness level of extracted indications.

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