Norton Masonry depressed center wheels have sharp silicon carbide, making these wheels suitable for use on masonry materials like concrete, brick, and asphalt. Reinforced 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. Depressed center wheels are flat faced with inset centers and are used for cutting off and portable grinding. The depressed center prevents the tool mandrel from gouging the workpiece. These wheels are typically used on flat workpieces at a slight angle with the workpiece. Depressed center wheels are frequently used with right-angle grinders. 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.