In a spark test, which property is estimated?

In a spark test, which property is estimated?

• A. Hardness
• B. Approximate carbon content
• C. Tensile strength
• D. Thermal conductivity

Answer: (B)

Spark testing is a quick way to gauge steel’s carbon content by watching the sparks produced when the metal is ground on a spinning wheel. The color, brightness, length, and how the sparks branch relate to how much carbon is present; higher carbon typically makes longer, brighter, more branched sparks. This makes the test useful for estimating approximate carbon content. Hardness, tensile strength, and thermal conductivity aren’t reliably read from spark patterns because they depend on different aspects of the metal’s structure and composition, which aren’t directly indicated by the sparks. So the purpose of a spark test is best described as estimating approximate carbon content.

Spark testing is a quick way to gauge steel’s carbon content by watching the sparks produced when the metal is ground on a spinning wheel. The color, brightness, length, and how the sparks branch relate to how much carbon is present; higher carbon typically makes longer, brighter, more branched sparks. This makes the test useful for estimating approximate carbon content.

Hardness, tensile strength, and thermal conductivity aren’t reliably read from spark patterns because they depend on different aspects of the metal’s structure and composition, which aren’t directly indicated by the sparks. So the purpose of a spark test is best described as estimating approximate carbon content.