Question

Identify the element which increases the Ms temperature of a steel containing 1.0% C:

• A. Chromium
• B. Copper
• C. Manganese
• D. Aluminium

Hint:

Aluminium is a ferrite stabilizer and increases Ms temperature, while most transition metals lower it by stabilizing austenite.

Answer 1

The Correct Option is D

Step 1: Understanding Ms Temperature
The Ms (Martensite start) temperature is the point at which transformation from austenite to martensite begins during cooling. The Ms temperature is sensitive to: - Carbon content, - Alloying elements. Step 2: Role of Alloying Elements
Most alloying elements such as Chromium, Manganese, and Nickel tend to decrease the Ms temperature because they stabilize austenite. Step 3: Aluminium's Effect
- Aluminium is a ferrite stabilizer, meaning it promotes the formation of ferrite and destabilizes austenite. - This leads to an increase in Ms temperature. - Aluminium also refines grain size and enhances toughness in some grades of steel. Step 4: Elimination of Incorrect Options
- Chromium, Copper, Manganese: All these elements tend to lower the Ms temperature by stabilizing the austenite phase. Conclusion: The element that increases the Ms temperature in steel with 1.0% C is Aluminium.