HKIE Professional Assessment - Materials Discipline Practice Questions - HKIE Professional Assessment - Materials Discipline (Hong Kong Institution Of Engineers) Exam

Access More Questions

A structural steel component is quenched in oil to achieve full martensite and then tempered at 550 °C. What primary microstructural change occurs during this high-temperature tempering stage?

Martensite recrystallizes into coarse proeutectoid ferrite and graphite flakes. Supersaturated body-centered tetragonal (BCT) martensite decomposes into fine transition carbides and tempered martensite (ferrite matrix with dispersed Fe3C particles), restoring toughness. Retained austenite transforms directly into coarse ledeburite. Grain growth accelerates, converting the steel back into unhardened austenite.

Correct Answer:

Supersaturated body-centered tetragonal (BCT) martensite decomposes into fine transition carbides and tempered martensite (ferrite matrix with dispersed Fe3C particles), restoring toughness.

Access more questions from this quiz

Continue to HKIE Professional Assessment - Materials Discipline Practice Questions - HKIE Professional Assessment - Materials Discipline (Hong Kong Institution of Engineers) Exam for more practice questions and the full quiz experience.

Access More Questions