Mechanical Engineering - Engineering Materials - Discussion

Usually invar or nickel steel.

It has a high thermal conductivity.

It has low coefficient of thermal expansion.

Yes, it is due to low thermal expansion.

The correct answer is: nickel-chrome steel.

Nickel-chrome steel, also known as 18/8 stainless steel, is a popular choice for making precision measuring instruments due to its unique properties:

1. High corrosion resistance.
2. Low thermal expansion.
3. High dimensional stability.
4. Good mechanical properties (strength, toughness).
5. Resistance to magnetic interference.

Nickel-chrome steel contains approximately 18% chromium and 8% nickel, which provides excellent corrosion resistance and stability. This makes it an ideal material for precision instruments, such as:

1. Gauges.
2. Calipers.
3. Micrometers.
4. Dial indicators.
5. Precision scales.

The other options are not correct because:

- Nickel steel is not as corrosion-resistant as nickel-chrome steel.
- High-speed steel is designed for high-temperature applications and is not typically used for precision measuring instruments.
- Chrome-vanadium steel is a high-strength steel alloy, but it is not as corrosion-resistant as nickel-chrome steel and may not provide the same level of dimensional stability.

The specific composition and properties of steel alloys can vary depending on the application and manufacturer.