Garbuzova КР2 Option 25

1. As a result of heat treatment, some machine parts must have a solid
Wear-resistant surface layer with a viscous core. For the manufacture of their chosen steel
15HF. Specify the composition and determine the steel group for its intended use. Assign a thermal and
Chemical-thermal treatment, give its justification, explaining the effect of doping on
Transformations occurring at all stages of heat treatment of this steel. Describe
Structure and properties of steel after heat treatment.
2. As a result of heat treatment, the crankshafts of ship and automobile
Engines should receive increased strength over the entire section (hardness 250 ... 280 HB).
To make them, steel 40ХФА was chosen. Specify the composition and determine the steel group by appointment.
Tion. Assign and justify the mode of heat treatment, explaining the effect of doping on
Transformation during the heat treatment of this steel. Describe the structure and properties of steel after
Heat treatment.
3. For parts operating in weak aggressive environments, steel 30X13 is used.
Specify the composition and determine the steel group by structure. Explain the purpose of chromium in this
Steel, assign and justify the mode of heat treatment.
4. The BrBNT-1.9 alloy was chosen for manufacturing current-conducting elastic elements.
Give the chemical composition, heat treatment and the resulting mechanical properties
Material. Describe the processes that occur during heat treatment, and explain the nature
Hardening in connection with the copper-beryllium state diagram.
5. Describe the sittals and methods for their production. The effect of the composition and magnitude of the crystals on
Properties of glass. Area of ​​application.