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Prolonged heating of pearlitic steel just below the eutectoid temperature produces a very soft structure called:

1. Martensite
2. Spheroidite
3. Bainite
4. Fine pearlite

Answer

B. Spheroidite

Solution

Cementite forms spheres in a ferrite matrix, maximizing machinability and ductility.

More Engineering Materials questions

1. Isothermal transformation of austenite at temperatures between those forming pearlite and martensite produces:
2. The ability of a steel to be hardened to a depth by quenching is called:
3. The diagram that shows the time needed for austenite to transform at a constant temperature is the:
4. Reheating quenched (martensitic) steel to a temperature below the eutectoid temperature to reduce brittleness is called:
5. Rapid cooling of steel from the austenite region in water, oil or brine is called:
6. Heating steel into the austenite region and cooling it in still air is called:
7. Heating steel into the austenite region and cooling it slowly in the furnace is called:
8. A steel with less than 0.76% carbon is called a:
9. The very hard, brittle microconstituent formed by rapidly quenching austenite is:
10. The lamellar mixture of ferrite and cementite formed by the eutectoid reaction in steel is called:

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