Norton Masonry Type 01 circular saw wheels use sharp silicon carbide, which is suitable for use on masonry materials like concrete, brick, and asphalt. Reinforced cutoff wheels are designed to resist breakage caused by severe cross-bending and are required on any operation where the work is not securely clamped. Resin bonds are organic bonds that soften under the heat of grinding, releasing dulled abrasive grains. Because of its forgiving nature, only an organic type bond is used in cutoff wheels. The resin-bonded wheel is more resilient than a vitrified wheel. The manufacturing term for a resin bond wheel is "cured," meaning the wheel has been heated to less than 500 degrees F. Straight (also called flat) wheels are the most common grinding wheel shape. Straight wheels are used for grinding on the periphery, or outside boundary edge, of the wheel and produce a slightly concave surface, called hollow ground, on the workpiece. These wheels can be used for cutting off, tool grinding (between centers or centerless), and removing mold marks and sand from castings, among others. They are frequently used with grinding machines. Using a harder grade wheel increases wheel life but also increases burn and requires more power, and decreases cut rate. Burn is the effect on a workpiece from thermal stress as abrasive cuts or rubs material away. The damage ranges from discoloration to cracking of the workpiece. Silicon carbide is a sharp, aggressive grain that offers high penetration, fast cutting, and high material removal even under light pressure. It is commonly used with softer materials like brass, plastics, and rubber, and abrasive materials like glass and enamel, but can wear out faster that aluminum oxide when used on wood. Abrasives are used for a variety of applications from shaping a part to fine finishing, depending on the grit size. Low grit numbers like 40 are coarse and are used for removing excess material and shaping a part. High grit numbers like 400 are fine and help to create a smooth surface finish. Norton Abrasives manufactures a wide variety of sanding, grinding, and polishing abrasives, and has been located in the United States since 1885. In 1990, Saint-Gobain purchased Norton, keeping its manufacturing facilities and offices in the same location. Norton/Saint-Gobain has been recognized as a Global 100 Sustainable Company, as well as earning ISO 9000 and 14001 certification for quality and environmental management standards.