Question

6. Plot the stress-strain response that you would expect to see if a specimen of annealed mild steel is subject to uniaxial tension. Indicate the following features on the graph that you draw i). Yield strength ii). Tensile strength iii). Failure strength iv). Failure strain. A sample of the same mild steel was then subject to cold-rolling to produce a 5% reduction in thickness and a second test specimen cut from t. What would the stress-strain response of this deformed material look like? Explain the reasons for the changes you have identified.

Answer 1

The above diagram shoes stress strain properties of mild steel.Now if the sample is subjected to cold rolling then stress strain response is as follows:

In above diagram we can see that the graph does not have yield point with yield plateau.In these type of curves the yield point is represented by a level at which stress strain curve become horizontal.Cold forming is believed to increase yield strength of steel .