Given exhaustive answers to questions 23 5 Option 2 control work on material for the training manual Garbuzova NE
1. Spring Steel 75 after correctly performed quenching and subsequent tempering has a hardness much higher than the pre-from adequate technical conditions. What caused this defect and how to fix it? Specify the structure and hardness that obespe¬chivayut high elastic properties of the springs.
2. For the manufacture of machine taps and dies steel R9F5 selected. Specify the composition; assign and justify the regime of heat treatment, explaining the effect of alloying elements on the transformation taking place at all stages of heat treatment. Describe the microstructure and properties of the steel after heat treatment.
3. For the production of power blades aviation gas turbines selected alloy HN77TYUR (EI437BU). Specify the composition of the group and determine the alloy as intended. Assign the mode of heat treatment and opi¬shite effect of temperature on the heat resistance characteristics of spla¬va compared to heat-resistant steel.
4. For the production of a number of parts used in shipbuilding brass LO70-1. Specify the composition and describe the structure of the alloy. Provide a general characterization of the mechanical properties of the alloy and the rationale of tin in a brass.
5. Describe the polar thermoplastics (polyamides, Penton, polycarbonates and others.). Their composition and properties primene¬niya region.