Garbuzova КР2 Option 07

Garbuzova КР2 Option 07

1. Assign a quenching temperature, a cooling medium and a tempering temperature of the springs from
Steel 65G, which must have a hardness of 45 ... 50 HRC. Describe the microstructure and properties.
2. As a result of thermal and chemical-thermal treatment, the gears must receive
A hard abrasion-resistant surface layer with a viscous core. To make them
18KhT steel is chosen. Specify the composition and determine the steel group for its intended use. Assign and
Justify the regime of thermal, chemical-thermal treatment, explaining the effect of doping on
Transformations occurring at all stages of heat treatment of this steel. Describe
Microstructure and properties of the surface and the core of the gear after heat treatment.
3. For some parts of precision instruments, an elinvar alloy is chosen. Specify the composition and
Determine which group the alloy belongs to by designation. Describe the impact
Alloying elements on the main characteristic of the alloy and the reasons for choosing this alloy.
4. For bronze details, bronze БРОЦ4-4-2,5 was chosen. Decipher the composition and describe
Structure of the alloy. Explain the purpose of the alloying elements. Give the characteristics
Mechanical properties of the alloy.
5. Phenol-formaldehyde laminates (polyethylene and vinyl plastic). Their properties and
Field of application in mechanical engineering.