Option 44
1. What is segregation? Causes of its occurrence and ways of elimination.
2. Whether metal hardening is preserved, if plastic deformation is carried out at
Temperature above the recrystallization temperature? Give a detailed explanation.
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 5.2% C. What is the structure of this
Alloy at room temperature and how such an alloy is called?
4. 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
Tempering temperature required to provide a hardness of 450 HB. Describe the transformations,
Which occurred in the steel during the quenching and tempering process, and obtained after the thermal
Processing structure.
5. Taps of steel U10 are hardened: the first - from the temperature of 760 ° C, and the second - from
Temperature 850 ° C. Apply the selected temperatures to the iron-cementite state diagram
Heat and explain which of these taps is hardened correctly, has higher cutting
Properties and why.