Bluing process

Aj = area of inside of surface for heaL transfer, such as coil, flat surface, or other barrier, sq ft/ft hi = inside heat transfer fluid side coefficient, in coil, flat plate, or other barrier, BLu/hr/sq fl/°F r0 = fouling resistance (factor) associated with fluid on outside (tank process side) of heat transfer... 

Both browning and bluing are essentially controlled artificial rusting processes using special oxidizing mixtures. The process consists of a number of stages ... 

The process of browning and bluing can be very time-consuming and labor intensive. Today, nearly all bluing (blackening) is done by the hot salt, black oxide process because of its speed and cheapness of materials. Hot salt... 

K. Kitahara, K. Seki and S. Suzuki, in Proceedings of the Emil-Warburg Symposium, Dynamical processes in condensed molecular systems , eds, A. Blu-men, J. Klafter and D. Haarer, World Scientific(1990). 

T. Blu, M. Unser, Quantitative Fourier analysis of approximation techniques Part I. Interpolators and projectors. IEEE Trans. Signal Processing 47, 2783-2795 (1999)... 

Teijin has developed a new PC film with improved optical qualities to the extent that it was the only such film chosen for the cover layer of the next generation Blu-ray DVD. Currently made by the use of a film casting process but destined to transfer to a new extrusion process which will significantly reduce costs. 

The bluing of steel has long been used as a process for producing a protective oxide on steel. When oiled and maintained, the thin oxide film prevents the rusting of steel in normal atmospheres. Such oxide coatings can be produced by exposing a clean steel surface to dry... 

After treatment, the black ferric-phosphate coating can be scrubbed off, leaving a fresh metal surface. Multiple applications of phosphoric acid may be required to remove all rust. The black phosphate coating can also be left in place, where it will provide moderate further corrosion resistance. (Such protection is also provided by the superficially similar Parkerizing and blued electrochemical conversion coating processes.)... 

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