Hello Abhijeet Moon,

although one would expect a distinct relationship between the difference or the ratio of UTS and YS relative to the strain hardening capability of a steel, the data rather suggest an "it depends" than a clear yes. Many parameter, like micro structure, alloys a.s.o., are influencing the behavior. But see for yourself: the article by KUZIAK et al. on "Advanced high strength steels for automotive industry" provides a lot data of different high strength steel grades and the analysis Pascal ANTOINE et al. discusses further basics in more detail as well as the other papers.

https://www.jstage.jst.go.jp/article/isijinternational/45/3/45_3_399/_pdf

http://www.pgatech.com.ph/documents/Significance%20of%20the%20Ratio%20of%20Tensile%20Strength%20to%20Yield%20Stress.PDF

http://www.acme.pwr.wroc.pl/repository/196/online.pdf

http://repository.up.ac.za/bitstream/handle/2263/10821/Tang_Effect(2008).pdf?sequence=1

Hello Abhijeet Moon,

although one would expect a distinct relationship between the difference or the ratio of UTS and YS relative to the strain hardening capability of a steel, the data rather suggest an "it depends" than a clear yes. Many parameter, like micro structure, alloys a.s.o., are influencing the behavior. But see for yourself: the article by KUZIAK et al. on "Advanced high strength steels for automotive industry" provides a lot data of different high strength steel grades and the analysis Pascal ANTOINE et al. discusses further basics in more detail as well as the other papers.

https://www.jstage.jst.go.jp/article/isijinternational/45/3/45_3_399/_pdf

http://www.pgatech.com.ph/documents/Significance%20of%20the%20Ratio%20of%20Tensile%20Strength%20to%20Yield%20Stress.PDF

http://www.acme.pwr.wroc.pl/repository/196/online.pdf

http://repository.up.ac.za/bitstream/handle/2263/10821/Tang_Effect(2008).pdf?sequence=1

I thank you for taking time out to answer my question.Dr. Ruediger Rentsch .Your advice was very helpful on the above topic and gave me a new perspective.

Whenever the material is subjected to tensile load, the strain rate is at lower rate compared to the corresponding tensile load/stress rate at the initial stages of deformation. The basic micro-structure due chemical constituents offers maximum resistance to any deformation initially, not only that the oxides of elements and other impurities also play role in giving resistance to flow of material. This is often called as strain hardening. The minimum stress and corresponding strength of material at which the stress and strain is linear called yield strength. Beyond this the material is subjected to plastic deformation. The maximum strength of material at which the load/stress is bearable called ultimate strength.

I looked into those ratios when I was working on my dissertation on aluminum alloys. I came to the conclusion that it is better to investigate the work hardening characteristics of the alloy rather than using a single number ratio or parameter (such as UTS/YS or strain hardening exponent, n). There is much to be learned by analyzing the entire stress-strain data. The Kocks-Mecking model is what I have used since then to analyze work (strain) hardening response of different alloys.

Higher UTS/YS ratio is one of the important parameter (for seismic resistance) in steel reinfocement bars, which is used in construction. Because more enery absorption capacity of steel before failure if UTS/YS ratio is high.