Recent Kawasaki Steel's development on size and shape measurement techniques for hot steel rolling processes is reviewed. First, a precision enhancement technique for a laser distance meter is described, then its rugged structure necessary for measurement in such tough environment as hot rolling processes is described in detail. A plate length meters and an inter-stand sensors for a hot strip mill are shown as developed size measurement techniques. Furthermore, plate shape meters and laser profile gauges for H-beams are depicted as specific examples of shape measurement techniques. (author)
It has been clarified by the present authors, based on the plasma nitriding of Fe-Cr alloys and Fe-Ti alloys carried out at the temperature under 550{degree}C hitherto, that an internal nitriding layer is formed due to the fine dispersion of the particles of Cr nitride and Ti nitride in {gamma}{prime} Fe4N layer on the specimen surface. In this study, the plasma nitriding of Fe-Cr alloys are carried out at 650{degree}C, and the effects of the solute (Cr) content on the structures, nitride and the thickness distribution are examined. The main results obtained therefrom are indicated hereafter. In accordance with the observation on the cross-sectional structure of the alloys, only the nitriding layer deduced as the dispersion and precipitation of the particles of Cr nitride from {alpha}-Fe of the mother phase is formed, while {gamma}{prime}-Fe4N layer, which is found at the temperature under 550{degree}C, is not formed. The nitride of Cr generated in the nitriding layer is CrN in all ...
Pitting corrosion measuring method for almunum alloys sold on the market was studied. By addition of a little quantity of Cu {sup ++} ion, corrosion potential of alminum alloys rapidly approachs to pitting corrosion potential in the solution including chloride. After Cu {sup ++} ion of 5ppm is added in advance into the solution including chrolide to measure the pitting corrosion potential, alminum alloy test pieces are imersed into the solution in the atmospheric air, then the stable corrosion potential is shown after three-minite imersion, and this potential is defined to the pitting corrosion potential. The pitting corrosion potential can be easily measured by this method stated above (copper ion method). The values measured by copper ion method is comparatively agreed with that measured by the existing potentio dynamic method. The pitting corrosion potential have a straight lined relation with the logarithm of Cl {sup -} concentration. As the measured values by potentio dynamic ...
Inert gas contamination, structure and mechanical properties of consolidated high-Ni alloy powder material were studied to improve its characteristics. In experiment, the chemical composition and fraction of porosity in cross sections of Alloy 625 powder were examined which was produced by Ar gas atomization method impinging supplemental gas jet onto accumulated alloy powder in the bottom of a tank for rapid cooling. The structure and mechanical properties of the alloy rod were also examined which was produced by hot hydrostatic pressing or hot extrusion of the powder filled into a capsule. As a result, although Ar content included in the powder produced by Ar gas atomization method decreased with reduction in grain size, the fine powder less than 22{mu}m still included Ar of nearly 0.5mass-ppm. Obvious correlation was found between the fraction of porosity in powder cross sections and Ar in the powder. Although cavities were detected in the consolidated powder material produced by hot ...
From a macroscopic point of view, corrosion of Zn alloy coated steel sheet occurs by the coating preceding corrosion mechanism; microscopically, however, the coated layer corrosion velocity in the tip of corrosion is different. In order to find the main factors of under-film corrosion of Zn and Zn-Fe alloy coatings in the salt water spray atmospheric exposure test, the correlation between point inflation-exfoliation width and chlorine penetration behavior, point adhesion, and the difference in chlorine penetration behavior due to alloy coating components were investigated. Consequently, the following results were obtained: 1. The better correlation was observed between chlorine penetration distance and point inflation-point exfoliation width. 2. The durability of coating against chlorine penetration improved by increase in point adhesion and Zn content in the coating layer. 3. Zn-Fe (10-20%) alloy coating showed better durability against chlorine penetration than pure Zn coating. 4. ...