A 0500 diameter 440 martensitic heat treated stainless steel

A 0.500\" diameter 440 martensitic, heat treated stainless steel bar is subjected to the following tensile loads:

a.) 20,000 #

b.) 36,000 #

c.) 80,000 #

Determine whether these loads are in the the plastic or elastic range. You may assume that the ratio of yied to tensile strength for this steel is 0.45.

Solution

We know that, In heat treted condition

yield strength of 440 martensitic stainless steel is around 279300 psi

a) 20,000 Pound load

Stress = 20,000 / [3.14 / 4 * 0.5 * 0.5]

Stress = 101859 psi < 279300 psi

So, in a) case there is elastic deformation happen

b) 36,000 Pound load

Stress = 36,000 / [3.14 / 4 * 0.5 * 0.5]

Stress = 183346 psi < 279300 psi

So, in b) case there is elastic deformation happen

c) 80,000 Pound load

Stress = 80,000 / [3.14 / 4 * 0.5 * 0.5]

Stress = 407436 psi > 279300 psi

So, in c) case there is plastic deformation happen