Based on the the two stress strain curves shown below Spring

Based on the the two stress strain curves shown below: Spring steel is tougher than plain carbon steel Spring steel is stiffer than plain carbon steel Plain carbon steel is tougher than spring steel Spring steel is more ductile than plain carbon steel Which one of the following hardness tests determines hardness by the depth of penetration? Brinell Vickers Knoop Rockwell Which one of the following phenomena is the primary mechanism for plastic deformation in Slip of dislocations Twinning Recovery Cold working

Solution

>> As, Toughness is the Area under Stress Strain Curve upto fracture

But from figure, we cant possibly compare the areas.

Whereas, due to more strain,

PlainCarbon Steel has more ductility than Spring Steel.

>> In Brinell Hardness Test, Hardness is calculated by depth of penetration of an indenter onto the workpiece, whose hardness is to be calculated.

>> When a layer under exertion of load slides from one place to another, then deformation occurs and as this is the permanent deformation, it is called plastic deformation.

So, due to Slip ofDislocations, Plastic Deformation of Metals occurs