AME 2 Q2

Answer:

B. Annealing is a heat treatment process that softens the metal and increases ductility.  

1. Annealing / Normalising - Heat Treatment - Bodycote plc

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Explanation:

Annealing is a heat treatment process that involves heating a metal to a specific temperature, holding it there for a period of time, and then cooling it slowly. This process softens the metal, making it more ductile and easier to form or machine.

Why the other answers are incorrect:

• A. Annealing is a heat treatment process that increases hardness and brittleness. This is incorrect. Annealing actually softens the metal and reduces brittleness.
• C. Annealing is a process to increase the strength of a metal. While annealing can improve the machinability of a metal, it generally reduces its strength.
• D. Annealing is a process to improve the conductivity of a metal. Annealing primarily affects the mechanical properties of a metal, not its electrical conductivity.

Annealing is specifically used to soften and improve the ductility of a metal, making it easier to form or machine.

Answer:

B. Hardening is a heat treatment process to increase hardness and reduce ductility.

Explanation:

Hardening is a heat treatment process that involves heating steel to a specific temperature (austenitizing) and then rapidly cooling it (quenching). This process dramatically increases the hardness of the steel but at the expense of ductility, making it more brittle.  

1. Metallurgy - Hardening, Treatments, Heat - Britannica

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2. How does the process of hardening steel work and what is its purpose? | Sacher CNC

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Hardening is often followed by tempering to improve toughness without significantly reducing hardness.

Why the other answers are incorrect:

• A. Hardening is a heat treatment process to soften steel. Hardening actually increases the hardness of the steel.
• C. Hardening is a process to improve the machinability of steel. While the hardening process might make the steel more difficult to machine, its primary purpose is to increase hardness.
• D. Hardening is a process to reduce the strength of steel. Hardening significantly increases the strength of steel, especially its resistance to wear and deformation.

Hardening is a heat treatment process specifically designed to increase the hardness of steel, often at the expense of ductility.

Answer:

C. Increasing carbon content increases strength but decreases ductility.  

1. Exploring the Impact of Carbon Content on Steel Strength and Ductility - AZoM

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Explanation:

As the carbon content in steel increases, it forms a harder carbide structure within the metal matrix. This hardening process increases the steel's strength. However, this increased hardness comes at the expense of ductility, making the steel more brittle.  

1. How does the addition of carbon affect steel's properties? - TutorChase

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2. Does Increasing Hardness Increase Strength? - Technische veren specialist | Tevema.com

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3. Carbon metal content, Classification of Steel and Alloy Steels - The Fabricator

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Therefore, while carbon is essential for enhancing steel's strength, it's a trade-off as it reduces the material's ability to deform without fracturing.

Why the other answers are incorrect:

• A. Increasing carbon content increases ductility and decreases strength. This is incorrect as increasing carbon content typically increases strength but decreases ductility.
• B. Increasing carbon content increases both strength and ductility. While strength increases with carbon content, ductility decreases.
• D. Carbon content has no significant effect on steel properties. This is incorrect as carbon is a key alloying element in steel and significantly affects its properties.

Increasing carbon content primarily increases the strength of steel but at the expense of ductility, making it more brittle.

Answer:

C. Normalizing is a heat treatment process that refines the grain structure and improves toughness.  

1. Normalizing: Definition, Purpose, How It Works, and Stages - Xometry

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Explanation:

Normalizing is a heat treatment process that involves heating the metal to a specific temperature above the critical point, holding it there for a sufficient time, and then allowing it to cool in air. This process refines the grain structure, reduces internal stresses, and improves the overall mechanical properties of the metal, including toughness and ductility.  

1. Difference between normalizing, tempering, annealing, quenching - JC casting

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2. Anneal, Normalize, & Stress Relieve - Clifton Steel

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While it doesn't soften the metal as much as annealing, it still improves its machinability and formability.

Why the other answers are incorrect:

• A. Normalizing is a heat treatment process that increases hardness and brittleness. Normalizing actually refines the grain structure and improves toughness, leading to a balance of strength and ductility.
• B. Normalizing is a heat treatment process that softens the metal and increases ductility. While normalizing does improve ductility, it primarily focuses on refining the grain structure and improving overall mechanical properties.
• D. Normalizing is a process to increase the conductivity of a metal. Normalizing primarily affects the mechanical properties of a metal, not its electrical conductivity.

Normalizing is a heat treatment process that primarily aims to refine the grain structure of the metal, which leads to improved toughness, ductility, and machinability.