Please answer part A and B . Thanks! Question 4 In the process of bending a meta
ID: 2073911 • Letter: P
Question
Please answer part A and B. Thanks!
Question 4 In the process of bending a metal plate 90degree, the plate experienced thinning at the bended corner, which is an indication of localized unstable plastic deformation. You've been asked to provide a solution to this problem. You cannot change the material but you can apply heat treatment processes (a) Considering the thickness of the plate, localized surface treatment is not considered. What is your recommendation and why? (b) With that suggested process in (a) what will be the yield stress, ultimate tensile stress, elastic modulus, uniform elongation and true strain change? Show the correlation for each item associated with the process you recommended.Explanation / Answer
Given that the in the process of bending a metal plate 90 degree, a plate is experienced thinning at the bended corner.
In finding the solution to this problem, we have to increase the strength of the metal in order to reduce the thinning process when bended.
Given that the material cannot be changed, this has to be done only by using the heat treatment process.
Hence in the heat treatment process there are following sub -processes
1. Metal hardening
2. Metal quenching
3. Metal tempering
Metal hardening: In this process the metal is heated at critical temperature and kept at this temeprature for one hour per inch of thickness and then cooled fastly to increase the hardness of the metal which makes the metal stronger.
Metal quenching: The hardened metal in the hardening process is taken next for the quenching process. In this process metal is quenched (immersed) in the oil or water to further harden the material.
Metal tempering: Tempering is the process to improve the combination of toughness and brittleness of the material. This treatment is done only after the quenching process.It is the process of reheating the metal at low temperatures. Hence the final result is the High tensile strength material and high stress.
(b)
We know young's modulus is ratio of stress to strain
Youngs modulus = stress/strain
hence if the stress is increased thenm youngs modulus is increased and strain is decreased.
Elongation is constant in the entire process.