Decision control work number 2 on materials science from the methodology Garbuzova N.E.
Variant 44

Tasks:

1. Select steel for making springs. Assign a heat treatment mode,
Describe the nature of the transformations that occur, the microstructure and the main properties of the springs after
processing. How can fatigue strength of springs be increased?

2. As a result of thermal and chemical-thermal treatment, the transmission shafts
car should receive a hard abrasion-resistant surface layer when viscous
the medium. For their manufacture, steel 15ХГН2ТА is chosen. Decipher the composition of steel and
determine the steel group for the purpose. Assign a heat treatment mode, bring it
justification, explaining the effect of doping on the transformations occurring during thermal
processing. Describe the microstructure and properties of the steel after heat treatment.

3. For the manufacture of vacuum equipment and the achievement of tight contacts between
metal and glass is used alloy platinum H48. Decode the composition and define the group
alloy to the destination. Describe the effect of alloying elements on the main characteristic
alloy and the reasons for choosing this alloy composition (in connection with the anomaly of the change in the thermal
coefficient of expansion).

4. The alloy AL1 is chosen for the pistons of the internal combustion engine. Decode the composition
alloy, specify the method of manufacturing parts, the heat treatment and nature
hardening. Describe the characteristics of the mechanical properties of the alloy.

5. Advantages and disadvantages of plastics. The use of plastics for die tools.