The microstructure and hence properties of many metals are very sensitive to the temperatures and pressures that they are exposed too. This can be taken advantage of during manufacturing to produce a component that has a specific set of properties as required by the application
The microstructure and hence properties of many metals are very sensitive to the temperatures and pressures that they are exposed too. This can be taken advantage of during manufacturing to produce a component that has a specific set of properties as required by the application. This assignment is intended to your understanding of the how metals achieve their mechanical properties through the use of temperature control.
In this assignment you must design a heat treatment schedule (hold temperatures, hold times and cooling rates) to produce a steel microstructure that has a combination of properties suitable for a bike frame. To do this you will need to understand the phase diagram and continuous cooling behaviour of the steel alloy provided, as well as determining the optimal combination of mechanical properties they believe the bike frame material requires.
Steel specimens will be provided in an annealed (or softened) condition with the nominal chemical composition of 0.3 wt% carbon, 0.9 wt% chromium, 0.5 wt% manganese, 0.2 wt% Molybdenum and 0.2 wt% silicon (balance is trace elements and Fe). There will be a number of furnaces and cooling/quenching media (such as water and oil) provided to select from (details of exact available temperatures and media will be provided closer to the date). Therefore the designed process must be achievable with the available facilities. Equipment provided to test the material after heat-treatment will include a hardness tester, tensile/compression frame, 3 point-bend test and metallography equipment to examine the microstructure.
1. A clear statement and justification of ALL the material property targets that have been specified for the heat-treated steel
2. A clear and detailed flow chart highlighting each step of the designed heat-treatment schedule
3. Expected/predicted microstructure and properties of the material at each step of the heat treatment schedule with evidence to justify these expectations
• Justification of the target properties for the final material
• Clear and accurate explanation of the designed heat treatment schedule
• Quality of evidence to support the expected microstructure and properties at each step in the heat treatment schedule
• Demonstration of fundamental knowledge in explaining why and how the microstructure should change to the desired form during each processing step, as well as in proposing thoughtful reasons for any discrepancies from expected results to actual results.
• Presentation and explanation of results
• Quality of written report – structure, grammar and presentation