Why does carbon have high solubility in -Fe than in -Fe HW of ETM 307 Chapter 11: Iron and Steel 100 points 1. What are austenite and the austenitizing heat treatment? (7.5 points) 2. What is...

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Why does carbon have high solubility in -Fe than in -Fe HW of ETM 307 Chapter 11: Iron and Steel 100 points 1. What are austenite and the austenitizing heat treatment? (7.5 points) 2. What is ferrite? (7.5 points) 3. What is cementite? (7.5 points) 4. What is pearlite? How to form pearlite? (7.5 points) 5. What is bainite? How to form bainite? (7.5 points) 6. What is martensite? How to form martensite? (7.5 points) 7. What are the key elements to generate high-strength, low-alloy steels? Please explain the roles of these alloying elements (10 points) 8. What is the key element to generate stainless steels? Why? What types of stainless steels are magnetic or nonmagnetic? (10 points) 9. What are the key elements to generate tool steels? Please explain the roles of these alloying elements (10 points) 10. What are cast irons? What are the roles of Si and Mg in cast irons? (10 points) Alloying elements play a critical role at achieving special properties and characteristics in iron. They cause solid-solution strengthening, precipitation strengthening and grain refinement as well as other favorable functions. C is the principal alloying element of iron, and it exists primarily as a form of carbide after reacting with iron or other alloying elements. The theme of the heat treatment of iron alloys is to adjust the distribution of C and carbide particles. This is also the key to understanding and designing the heat treatment of iron alloys. 11. The following figure is the TTT diagram of a hypoeutectic steel, and the pink line is the cooling history. Please describe the microstructure at each of the six points indicated along the line. (15 points) Temperature (°C) Time (s) MS M90 M50 (-Fe+(-Fe 100 50 Bainite Pearlite 900 800 0 700 600 500 400 300 200 100 1 day 1 hour 1 min 105 104 103 102 10 1 0.1 1 2 3 4 5 6 PAGE MSU © Qingzhou Xu