Question

please make sure it is correct

Heating a low - medium carbon steel sample above its recrystallization temperature and while quenching the heated sample in brine solution would lead a microstructure with shapes. Cold-working leads to a grain structure O elongated, equi-axed oll needle like, elongated O coarse, pear latic OIV fine, pearlatic

Answer 1

Answer:

Correct option is 2nd one:Needle like, elongated

Reason:

Generally quenching is used for hardening the various components in the heat treatment process. Mostly quenching is applicable to most type of steels.By heat treatmnet and quenching process, the soft and high temperature austenite is converted to hard martensite.

For getting the martensite structure, cooling rate should be ery fast and to attain very high cooling rate the brine solution is used as brine solution provides the fast cooling. Fast cooling is useful as it avoids the formation of bainite and pearlite.

As martensite is very hard and have needle like structure so when low medium carbon steels is quenched with the brine solution, it leads to needle like microstructure

In case of cold working, cold working is the plastic deformation of materials which is done below the recrystallisation temperature. It is known as the permanent deformation. When the cold work is done the workpiece is pressed and the compression takes place by which the grains are elongated and dislocations piles up and also leads to strength increase