Concept explainers
A part made from annealed AISI 1018 steel undergoes a 20 percent cold-work operation.
- a) Obtain the yield strength and ultimate strength before and after the cold-work operation. Determine the percent increase in each strength.
- b) Determine the ratios of ultimate strength to yield strength before and after the cold-work operation. What does the result indicate about the change of ductility of the part?
(a)
The yield strength if annealed AISI 1018 steel undergoes a 20 percent cold-work operation.
The ultimate strength if annealed AISI 1018 steel undergoes a 20 percent cold-work operation.
The percentage increase in yield strength.
The percentage increase in ultimate strength.
Answer to Problem 9P
The yield strength if annealed AISI 1018 steel undergoes a 20 percent cold-work operation is
The ultimate strength if annealed AISI 1018 steel undergoes a 20 percent cold-work operation
The percentage increase in yield strength is
The percentage increase in ultimate strength is
Explanation of Solution
Write the expression for work load factor and area.
Here, the original area is
Write the expression for true strain.
Here, the true strain is
Calculate the new yield strength after cold work.
Here, the new yield strength is
Calculate the new ultimate strength after cold work.
Here, the new ultimate strength after clod work is
Calculate the percentage increase in yield strength.
Here, the percentage increase in yield strength is
Calculate the percentage increase in ultimate strength.
Here, the percentage increase in ultimate strength is
Conclusion:
Refer to Table A-22 “Results of Tensile Test of Some Metals” for annealed AISI 1018 steel.
Obtain the yield strength as
The steel undergoes
Substitute
Substitute
Substitute
Thus, the yield strength is
Substitute
Thus, the percentage increase in yield strength is
Substitute
Thus, the ultimate strength is
Substitute
Thus, the percentage increase in ultimate strength is
(b)
The ratio of ultimate and yield strength before cold-work operation.
The ratio of ultimate and yield strength after cold-work operation and explain the ductility of part with the help of result.
Answer to Problem 9P
The ratio of ultimate and yield strength before cold-work operation is
The ratio of ultimate and yield strength after cold-work operation is
Explanation of Solution
Calculate the ratio of ultimate strength to yield strength before cold work.
Here, the ratio of ultimate strength to yield strength is
Calculate the ratio of ultimate strength to yield strength after cold work.
Here, the ratio of ultimate strength to yield strength after cold work is
Conclusion:
Substitute
Thus, the ratio of ultimate strength to yield strength before cold work is
Substitute
Thus, the ratio of ultimate strength to yield strength after cold work is
From the calculated value of
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Chapter 2 Solutions
Shigley's Mechanical Engineering Design (McGraw-Hill Series in Mechanical Engineering)
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