Abstract: A bonded abrasive tool, having a structure permeable to fluid flow, comprises sintered agglomerates of a plurality of abrasive grains and a binding material, the binding material being characterized by a melting temperature between 500 and 1400° C, and the sintered agglomerates having a loose packing density of ?1.6 g/cc and three-dimensional shape; a bond material; and about 35-80 volume % total porosity, including at least 30 volume % interconnected porosity. Methods for making the sintered agglomerates and abrasive tools containing the sintered agglomerates are described.

Abstract: A bonded abrasive tool, having a structure permeable to fluid flow, comprises sintered agglomerates of a plurality of abrasive grains and a binding material, the binding material being characterized by a melting temperature between 500 and 1400° C., and the sintered agglomerates having a loose packing density of ?1.6 g/cc and three-dimensional shape; a bond material; and about 35–80 volume % total porosity, including at least 30 volume % interconnected porosity. Methods for making the sintered agglomerates and abrasive tools containing the sintered agglomerates are described.

Abstract: A bonded abrasive tool, having a structure permeable to fluid flow, comprises sintered agglomerates of a plurality of abrasive grains and a binding material, the binding material being characterized by a melting temperature between 500 and 1400° C., and the sintered agglomerates having a loose packing density of ?1.6 g/cc and three-dimensional shape; a bond material; and about 35-80 volume % total porosity, including at least 30 volume % interconnected porosity. Methods for making the sintered agglomerates and abrasive tools containing the sintered agglomerates are described.

Abstract: A bonded abrasive tool, having a structure permeable to fluid flow, comprises sintered agglomerates of a plurality of abrasive grains and a binding material, the binding material being characterized by a melting temperature between 500 and 1400° C., and the sintered agglomerates having a loose packing density of ≦1.6 g/cc and three-dimensional shape; a bond material; and about 35-80 volume % total porosity, including at least 30 volume % interconnected porosity. Methods for making the sintered agglomerates and abrasive tools containing the sintered agglomerates are described.

Abstract: A bonded abrasive tool, having a structure permeable to fluid flow, comprises sintered agglomerates of a plurality of abrasive grains and a binding material, the binding material being characterized by a melting temperature between 500 and 1400° C., and the sintered agglomerates having a loose packing density of ≦1.6 g/cc and three-dimensional shape; a bond material; and about 35-80 volume % total porosity, including at least 30 volume % interconnected porosity. Methods for making the sintered agglomerates and abrasive tools containing the sintered agglomerates are described.

Abstract: A grinding wheel is provided for grinding the fire deck of an engine block. The grinding wheel, includes a first annular grinding element disposed concentrically with the wheel on a backing plate. The first annular grinding element includes a first abrasive component of either metal brazed single layer abrasive components or abrasive components comprising grain bonded in a porous matrix having about 55 to 80 volume percent interconnected porosity. The wheel preferably has a second annular grinding element disposed concentrically inward of the first annular grinding element. The first annular grinding element preferably comprises a single layer of relatively course diamond abrasive component brazed on a metallic substrate, while the second annular grinding element preferably comprises a single layer of relatively fine diamond abrasive components brazed on a similar substrate.

Abstract: A method of obtaining superabrasive grinding performance from tools employing less expensive, non-superabrasive conventional abrasive grain involves operating the conventional abrasive tool at ultra high tangential contact speed, (that is at least about 125 m/s). Such ultra high operating speeds can be achieved with segmented abrasive grinding wheels having segments formed from vitreous or resin bonded particles of aluminum oxide, silicon oxide, iron oxide, molybdenum oxide, vanadium oxide, tungsten carbide, silicon carbide and the like. The abrasive segments can be cemented to the core of the tool with an adhesive such as epoxy cement. Abrasive segments can be made to a significantly greater depth than traditional superabrasive-bearing segments, and consequently, should provide long life as well as high performance. Additionally, conventional abrasive segments are easier to true and dress and to make into intricate profiles for grinding complex shaped work pieces.

Abstract: Bonded abrasive products comprising alumina-based abrasive grains and a geopolymer bond system are significantly improved by providing the grain with a vitreous coating before incorporation in the geopolymer bond.

Abstract: A method is provided for machining the fire deck of an engine block. The method includes providing a grinding wheel having an outer annular grinding element disposed concentrically or the wheel may be provided with an inner annular grinding element disposed concentrically inward of an outer element. The outer element comprises a single layer of relatively coarse diamond abrasive brazed on a metallic substrate, while the inner element comprises a single layer of relatively fine diamond abrasive brazed on a similar substrate. The outer grinding element and the inner element if utilized, is formed as a discrete unit individually fastened to a backing plate to facilitate independent height adjustment of the elements relative the backing plate. The method further comprises orienting the grinding wheel with its axis of rotation at a predetermined oblique angle a relative the fire deck.

Abstract: An abrasive article having certain minimum levels of permeability to fluids comprises about 40 to 80%, by volume interconnected porosity and effective amounts of abrasive grain and bond to carry out soft grinding and deep cut grinding operations. The high permeability to the passage of fluids and interconnected porosity provides an open structure of channels to permit the passage of fluid through the abrasive article and the removal of swarf from the workpiece during grinding operations.

Abstract: An efficient method for manufacturing bonded abrasive articles comprises the use of elongated abrasive grain having a length to cross-sectional width aspect ratio of at least 5:1 to yield abrasive articles which are highly permeable to the passage of fluids. A method for measuring permeability is provided. The abrasive articles are used to carry out soft grinding and deep cut grinding operations. The permeable abrasive articles provide an open structure of pores and channels permitting the passage of fluid through the abrasive article and the removal of swarf from the workpiece during grinding operations.

Abstract: The invention is a process of manufacturing an abrasive article with the steps of forming an abrasive article in the unfired state comprising an abrasive, a vitreous bond and a polymer resin wherein the polymer resin has an elastic modulus greater than about 2.0.times.10.sup.9 Pa, a weight gain due to moisture absorption when measured after exposure to a 90.degree. C. temperature and 85% relative humidity for 10 hours of less than about 2 wt % and a weight loss on firing in a nitrogen atmosphere at 5.degree. C. per minute to 550.degree. C. of greater than about 95 wt %, and firing the abrasive article thereby decomposing the polymer resin and creating pores in the abrasive article. The invention further includes the abrasive article formed in the unfired state by the above process.