Materials kontrolnaya2 / 30 version of Garbuzova

Complete answers to 5 questions of the 30th variant of the 2 control work on materials science according to the methodology of N. Garbuzova are given.
1. Assign a mode of heat treatment of dies of cold press¬povki from steel U10. Give its justification and describe the structure and properties of the stamps. Explain why small stamps are made from this steel.
2. As a result of thermal and chemical-thermal treatment, worms should obtain a hard, wear-resistant surface layer with a viscous core. To make them, steel 12Х2Н4ВА has been chosen. Specify the composition of the steel and determine the steel group for its intended use. Assign and justify the regime of thermal and chemical-thermal treatment, explaining the effect of doping on the transformations occurring at all stages of processing of this steel. Describe the microstructure and properties of worms in the finished state.
3. Assign stainless steel for the manufacture of parts that work in acetic acid at temperatures up to 40 ° C. Give the chemical composition of the steel, the necessary heat treatment and a semi-finished structure. Explain the corrosion resistance of the material and the role of each alloying element.
4. Assign a grade of aluminum bronze for the manufacture of small critical parts (bushings, flanges, etc.). Specify its composition, describe the structure using the copper-aluminum state diagram and the main properties of bronze.
5. Describe the thermoplastic and thermosetting polymers and specify the difference between them.