Dull grading

Dull Grading of Roller Cone Bits. The grading is accomplished by using an eight-column dull code as follows [46]. 

The section describes the first lADC standardized system for dull grading natural diamond, PDC, and TSP (thermally stable polycrystalline diamond) bits, otherwise known as fixed cutter bits [55]. The new system is consistent with the recently revised dull grading system for roller bits. It describes the condition of the cutting structure, the primary (with location) and secondary dull characteristics, the gage condition, and the reason the bit was pulled. 

The format of the dull grading system is shown in Figure 4-165. For completeness, Figure 4-165 contains all of the codes needed to dull grade fixed cutter bits and roller bits. Those codes which apply to fixed cutter bits are in boldface. 

Figure 4-165. I ADC bit dull grading codes—bold characters for fixed-cutter bits [55]. (Courtesy SPE.)...

The first two spaces of the dull grading format are used for the inner two-thirds of the bit radius and the outer one-third of the bit radius, as shown... 

The fifth space will always be an X for fixed cutter bits, since there are no bearings. This space can be used to distinguish dull grades for fixed cutter bits from dull grades for roller bits. 

Clark, D. A., et al., Application of the new lADC dull grading system for fixed cutter bits, SPE/IADC 1645, Proc. 1987 SPE/IADC Drilling Conference, New Orleans, March 15-18, 1987, pp. 851-858. 

Uses Coating binder for paper/paperboard, size press, wallpaper applies., esp. mod. gloss level publication grades and matte and dull grades Features Outstanding wet and dry pick resist. exc. blister resist, for web offset grades... 

With sheet or pipe, multilayer coextmsion can be used. SoHd outer-soHd core coextmsion can place an ABS grade on the outside that has special attributes such as color, dullness, chemical resistance, static dissipation, or fire-retardancy over a core ABS that is less expensive or even regtind. 

Commercial attention focuses on the derivatives of the pyranthrone molecule at a varying level of halogenation. Most are orange but others exhibit a dull medium to bluish red shade. Due to their good weatherfastness pyranthrone pigments are used for high grade industrial finishes. 

The pigment provides slightly dull yellowish red shades. Commercially available grades of P.R.267 have as yet not been met on the market. In Japan the pigment is primarily recommended for the use in printing inks. 

P.O.59 is a nickel complex which affords very dull yellowish shades of orange. The pigment was used to match deep to medium shades in the yellow and orange part of the spectrum for high grade industrial finishes, as well as for architectural paints. 

Aniline Black provides a deep, neutral shade of black. Extensive absorption and little scattering make for good hiding power. The commercial grades cover a comparatively wide range of particle size distributions. The types with fine particle sizes in particular provide characteristically dull, velvety effects in finishes and... 

Greenstone is a low-grade metamorphic rock derived from a basic, low-silica parent rock like diabase or basalt. It gets its name from the dull greenish color of the fresh rock. Like other iron-rich rocks, when greenstone weathers it usually yields a red soil. 

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