C.B.M is ceramic backing material suitable for shipbuilding, marine facilities, plants and other steel structures and is widely used for one side welding technique such as CO2 semiautomatic welding and automatic welding.     C.B.M makes the back gauging technique unnecessary and contributes greatly to enhancing productivity and cost reduction by realizing one side welding.       COMPOSITON AND APPLICATION OF CERAMIC BACKING MATERIAL     SHAPE OF C.B.M APPLICATION OF C.B.M FEATURES OF CERAMIC BACKING MATERIAL   C.B.M is a fine ceramics product composed of adequately mixed natural inorganic substances(kaolin, talc, alumina, magnesia etc.) that are heat-treated at high temperatures of 1,350℃ ~ 1,400 ℃/span.   Since C.B.M is heat-treated at high temperatures it's shock resistance to rapid heating and cooling is excellent ( coefficient of thermal expansion is 1.85 - 2.5 ×10-6 at 1,000 ℃ ) and maintains superb stability against the high temperatures created good beads on the back side.   C.B.M has excellent characteristics of ceramic such as anti-acid, anti-chemicals and anti-corrosion and also caused no change or reaction of steel at the time of welding.