Option 26
1. Explain the essence of the phenomenon of dendritic liquation and methods of its elimination.
2. What are the standard characteristics of mechanical properties
Plasticity of metals and alloys? How are they determined?
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 1.2% C. What is the structure of this
Alloy at room temperature and how such an alloy is called?
4. How can a coarse-grained structure in forged steel 30 be eliminated? Using
Diagram of iron-cementite state, justify the choice of the heat treatment mode for
Correction of the structure. Describe the structural transformations and the nature of the change in properties.
5. Indicate the temperatures at which the process of strength nitriding is performed.
Explain why nitriding is not performed at temperatures below 500 and above 700 ° C
(Using the iron-nitrogen state diagram). What are the grades of steels used for
Nitriding, and describe the full cycle of their thermal and chemical-thermal treatment