# Ultimate tensile stress of material

• songoku
In summary, the conversation discusses the labels of the stress-strain curve for a metal and which one corresponds to the Ultimate Tensile Stress (UTS). The answer key states that the UTS is labeled as B, but the person believes it should be labeled as A. They also mention that the Wikipedia article on UTS supports their belief, as long as the "True Stress-Strain" curve is considered instead of the "Engineering Stress-Strain" curve. However, someone else points out that point B could also be considered the breaking point due to the material necking and reducing its cross-section. They provide a resource for further reading on the topic.

#### songoku

Homework Statement
The diagram shows the stress-strain curve for a metal. Which label corresponds to the Ultimate Tensile Stress for this metal?
Relevant Equations
None

I don't understand why B. I would think B is the breaking point.

Thanks

songoku said:
Homework Statement:: The diagram shows the stress-strain curve for a metal. Which label corresponds to the Ultimate Tensile Stress for this metal?
Relevant Equations:: None

I would think B is the breaking point
Is there a difference?
https://en.wikipedia.org/wiki/Ultimate_tensile_strength

Edit… I misread the article at that link the first time. Reading it again, it agrees with you that A is the UTS.

Last edited:
songoku
The “Engineering Stress-Strain”curve is misleading in that area. The “True Stress-Strain” curve is what you need to consider.

songoku
songoku said:
Homework Statement:: The diagram shows the stress-strain curve for a metal. Which label corresponds to the Ultimate Tensile Stress for this metal?
Relevant Equations:: None

View attachment 313238

I don't understand why B. I would think B is the breaking

A is UTS and B is Breaking point

songoku
songoku and erobz
Thank you very much for the help haruspex, erobz, Martin TSK, Lnewqban

erobz and Lnewqban