Question

compare strength and ductility of coarse pear lite, define pearlite and spheroidite

Answer 1

Coarse pearlite structure has better ductility and toughness compared to fine pearlite structure but fine pearlite structure has better strength compared to coarse pearlite structure.

1. Spheroidite - refers to a microscopic constituent in some steels, composed of spherically-shaped cementite particles in an alpha ferrite matrix. Spheroidite is formed when carbon steel is heated for more than 30 hours at temperatures exceeding 690°C. This prolonged exposure to such temperature extremes results in a structure of spheres or rods of cementite within a primary structure.

1. Pearlite is a mixture of alpha- ferrite and cementite forming distinct layers or bands in slowly cooled carbon steels. It is an iron alloy that contains around 88% ferrite and 12% cementite.