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Question 23

At elevated temperature, the carbide phases in certain carbon steels are unstable and may decompose into _______. This decomposition is known as graphitization.

    Correct Answer: B

    At elevated temperatures, the carbide phases in certain carbon steels are unstable and can decompose into graphite nodules. This process is known as graphitization.

Discussion
ahmadmmOption: B

Graphitization is a change in the microstructure of certain carbon steels and ½Mo steels after long-term operation in the 800 °F to 1100 °F (425 °C to 595 °C) range. At these temperatures, the carbide phases in these steels are unstable and decompose into graphite nodules.