Option 38
1. What is the essence of the metal, ionic and covalent types of connection?
2. In what way can plasticity of cold-rolled copper tapes be restored?
Assign a heat treatment mode and describe the nature of the processes occurring.
3. Draw a diagram of the iron-iron carbide state, indicate the structural
Components in all areas of the diagram, describe the transformations and construct a curve
Cooling (using the phase rule) for an alloy containing 0.2% C. What is the structure of this
Alloy at room temperature and how such an alloy is called?
4. Using the iron-cementite state diagram, describe the structural transformations,
Occurring at heating of steel U10. Specify the critical points and select the optimal
Mode of heating this steel for quenching. Describe this type of heat treatment and describe
Those obtained structure and properties of steel.
5. Using the state diagram, iron-iron carbide and the hardness change curve in
Depending on tempering temperature, assign a hardening temperature for carbon steel 40 and
Leave required to provide hardness of 250 HB. Describe the transformations taking place
During heat treatment, and the structure obtained after processing.