Roughness and Hardness of 60/40 Cu-Zn Alloy
— The functional performance of machined components, often, depends on surface topography, hardness, nature of stress and strain induced on the surface, etc. Invariably, surfaces of metallic components obtained by turning, milling, etc., consist of irregularities such as machining marks are responsible for the above. Surface finishing/coating processes used to produce improved surface quality/textures are classified as chip-removal and chip-less processes. Burnishing is chip-less cold working process carried out to improve surface finish, hardness and resistance to fatigue and corrosion; not obtainable by other surface coating and surface treatment processes. It is a very simple, but effective method which improves surface characteristics and is reported to introduce compressive stresses. micro-irregularities start moving in the direction of the newly formed surface. The grain structure is condensed, producing a smoother and harder surface with superior load-carrying and wear-resistant capabilities. 2 + 0.0525X 4 + 0.0125X 1 X 4 − 0.02X X 4 − 0.0375X 3 X 4 Hv=160.625 − 2.37 5X 1 + 5.125X 2 + 1.875X 3 + 4.375X 4 − 1.625X 1 X 4 + 4.375X 2 X 4 − 2.375X 3 X 4 High surface microhardness (175H V ) was obtained at 400rpm, 2passes, 0.05mm/rev and 15kgf., and high surface finish (0.20µm) was achieved at 30kgf, 0.1mm/rev, 112rpm and single pass. In other words, surface finish improved by 350% and microhardness improved by 21% compared to as machined conditions.
EFFECT OF BALL BURNISHING PARAMETERS ON SURFACE ROUGHNESS USING SURFACE ROUGHNESS METHODOLOGY
Burnishing, a plastic deformation process, can be used to finish surfaces by plastic deformation of surface irregularities. A simple inexpensive and newly designed balburnishing tool, with interchangeable adapter for using different ball diameters, was used throughout the experimental work. In present paper reports on the optimization of the surface finish produced by ball burnishing process, using the surface response (RMS) methodology. A second order mathematical model correlating four predominant process parameters, viz, burnishing force, speed, ball diameter and number of tool pass, with the surface roughness parameter has been obtained. The model can be used in selecting the optimum process parameters for obtaining a desired control surface finish.
Wood Microbiology: Decay and Its Prevention
Introductory text on the principles of decay and discoloration processes in wood, with emphasis on the major fungal damages which may develop during the growth, storage, and use of wood. The characteristics, detection, effects, and control of microbial attacks are stressed. Provides a synthesis of the current literature on wood microbiology, a rapidly expanding field of study. (Abstractor's note: This is an important resource for conservation researchers studying the decay of wood in art and architecture.) The following is a list of chapter headings: 1) Introduction to wood microbiology; 2) Wood deterioration agents; 3) Characteristics and classification of fungi and bacteria; 4) Factors affecting the growth and survival of fungi in wood (fungal ecology); 5) Fungal metabolism in relation to wood decay; 6) The decay setting: some structural, chemical, and moisture features of wood in relation to decay development; 7) General features, recognition, and anatomical aspects of wood decay; 8) Chemical changes in wood caused by decay fungi; 9) Ultrastructural features of wood decay; 10) Changes caused by decay fungi in the strength and physical properties of wood; 11) Colonization and microbial interactions in wood decay; 12) Decays originating in the stems of living trees; 13) Biodeterioration of stored wood and its control; 14) Wood stains and discolorations; 15) Decay problems associated with some major uses of wood products; 16) Detection of internal decay; 17) Paint mildew and related degradative problems; 18) Natural decay resistance (wood durability); 19) Chemical protection of wood (wood preservation); and 20) Some trends in wood microbiology research and a new emphasis (biotechnology). -- AATA