Quenching: The Heat Treatment Process

Material science

LO2

Quenching

Quenching is heat treatment process, the material is rapidly cooled of workpiece to obtain certain material properties. low temperature processes, such as phase transformations, from occurring by only providing a narrow window of time in which the reaction is both thermodynamically favourable and kinetically accessible. It increases hardeness of both alloy and plastics and reduce crystalliity.

Effect of quenching

The structure of material before material quenching process is a pearlite grain structure that is uniform and lamellar. Pearlite is a mixture of ferrite and cementite formed when steel or cast iron are manufactured and cooled at a slow rate after quenching. The structure of the

Pearlite is a mixture of ferrite and cementite formed when steel or cast iron are manufactured and cooled at a slow rate. The microstructure of material after quenching turn into martensite as a fine, needle like grain strucuture.

Normalizing

Normalizing heat treatment is a process in which metal is heated above critical temperature, holding for a period of time long enough for transformation to occur, and air cooling.it forms a carbide size and distribution which facilitates later heat treatrement opertions and produces a more uniform final product

Effect of normalizing

1. it refines the grain structure and ekiminate coarse grained structures obtained in previous working operations such as rolling and forging etc.

2. It modify and improves cast dendritic structure and reduce segregation

3. it improves machinability of low carbon steel

4. it improve dimensional