1) A cold heading operation is performed to produce the head on a steel nail. The strength coefficient for this steel is \( 600 \mathrm{MPa} \), and the strain hardening exponent is 0.22 . Coefficient of friction at the die-work interface is 0.14 . The wire stock out of which the nail is made is \( 5.00 \mathrm{~mm} \) in diameter. The head is to have a diameter of \( 9.5 \mathrm{~mm} \) and a thickness of \( 1.6 \mathrm{~mm} \). The final length of the nail is \( 120 \mathrm{~mm} \). (a) What length of stock must project out of the die in order to provide sufficient volume of material for this upsetting operation? (b) Compute the maximum force that the punch must apply to form the head in this open-die operation. 2) A upset forging operation is performed in an open die. The initial size of the workpart is: \( D o=63 \mathrm{~mm} \), and ho \( =100 \mathrm{~mm} \). The part is upset to a diameter \( =70 \mathrm{~mm} \). The work metal has a flow curve with strength coefficient \( =600 \mathrm{MPa} \) and strain hardening exponent \( =0.22 \). Coefficient of friction at the die-work interface \( =0.40 \). Determine (a) final height of the part, and (b) maximum force in the operation.
Added by Kevin M.
Close
Your feedback will help us improve your experience
Keshav Singh and 76 other Physics 101 Mechanics educators are ready to help you.
Ask a new question
Labs
Want to see this concept in action?
Explore this concept interactively to see how it behaves as you change inputs.
Key Concepts
Recommended Videos
For a certain type of steel, stress is proportional to strain with Young's modulus as given in Table $12.1 .$ The steel has the density listed for iron in Table $15.1 .$ It bends permanently if subjected to compressive stress greater than its elastic limit, $\sigma=400 \mathrm{MPa}$, also called its yield strength. A rod $80.0 \mathrm{~cm}$ long, made of this steel, is projected at $12.0 \mathrm{~m} / \mathrm{s}$ straight at a hard wall. (a) Find the speed of compressional waves moving along the rod. (b) After the front end of the rod hits the wall and stops, the hack end of the rod keeps moving, as described by Newton's first law, until it is stopped by the excess pressure in a sound wave moving back through the rod. How much time elapses before the back end of the rod gets the message? (c) How far has the back end of the rod moved in this time? (d) Find the strain in the rod and (e) the stress. (f) If it is not to fail, show that the maximum impact speed a rod can have is given by the expression $\sigma / \sqrt{\rho} Y$.
A cylindrical metal specimen $15.0 \mathrm{~mm}(0.59$ in.) in diameter and $150 \mathrm{~mm}(5.9$ in.) long is to be subjected to a tensile stress of $50 \mathrm{MPa}$ (7250 psi); at this stress level, the resulting deformation will be totally elastic. (a) If the elongation must be less than $0.072 \mathrm{~mm}$ $\left(2.83 \times 10^{-3}\right.$ in.), which of the metals in Table $6.1$ are suitable candidates? Why? (b) If, in addition, the maximum permissible diameter decrease is $2.3 \times 10^{-3} \mathrm{~mm}\left(9.1 \times 10^{-5}\right.$ in.) when the tensile stress of $50 \mathrm{MPa}$ is applied, which of the metals that satisfy the criterion in part (a) are suitable candidates? Why?
A cylindrical specimen of stainless steel having a diameter of $12.8 \mathrm{mm}(0.505 \text { in. })$ and a gauge length of $50.800 \mathrm{mm}(2.000 \text { in. })$ is pulled in tension. Use the load-elongation characteristics tabulated below to complete parts (a) through (f). (a) Plot the data as engineering stress versus engineering strain. (b) Compute the modulus of elasticity. (c) Determine the yield strength at a strain offset of 0.002. (d) Determine the tensile strength of this alloy. (e) What is the approximate ductility, in percent elongation? (f) Compute the modulus of resilience.
Recommended Textbooks
University Physics with Modern Physics
Physics: Principles with Applications
Fundamentals of Physics
Watch the video solution with this free unlock.
EMAIL
PASSWORD