Decision control work number 2 on materials science from the methodology Garbuzova N.E.
Variant 42

Tasks:

1. Assign a quenching temperature, a cooling medium and a tempering temperature of the countersink
of steel U12A. Describe the nature of the transformations that occur, the microstructure and hardness
after heat treatment.

2. As a result of heat treatment, the parts of the machines should receive an increased
strength over the entire section (hardness 250 ... 280 HB). To make them, steel ZOKGS was chosen.
Specify the composition and determine the steel group for the purpose. Assign a thermal mode
processing, give its justification, explaining the effect of doping on transformations,
occurring during heat treatment. Describe the structure and properties of steel after
heat treatment.

3. Assign stainless steel for the manufacture of parts operating in an acetic environment
acid at a temperature of no higher than 40 ° C. Give the chemical composition of the steel required
heat treatment, the resulting structure. Explain the physical nature of the corrosive
stability of steel and the role of each alloying element.

4. For soldering in the glass vacuum devices of conductors, an alloy of kovar 29NK is used.
Specify the alloy composition, properties and reasons for its application in this field of technology.

5. Describe the thermo- and thermosetting plastics. What is their difference in structure and properties?