What Is Nickel Chromium Molybdenum Steel?
Nickel Chromium Molybdenum Steel is an alloy steel that includes carbon steel with added nickel, chromium, and molybdenum. This combination is designed to increase the steel’s strength at high temperatures and enhance its hardenability and tempering properties. Commonly used as skin-hardening steel, it benefits from surface hardening treatments such as heat treatment, carburizing, and nitriding.
Applications of Nickel Chromium Molybdenum Steel
This steel is known for its exceptional mechanical properties among alloy steels and is often used in applications requiring high strength, such as aircraft parts. Despite its high strength, it is challenging to weld and process. Among its seven grades, nickel chromium molybdenum steel is the most mechanically superior, though it is also more expensive due to the inclusion of nickel.
Types of Nickel Chromium Molybdenum Steel
Examples of this steel include:
- SNCM439 and SNCM447: Known for their high toughness and suitability for large parts.
- SNCM447: Offers the highest strength and hardness among these steels, making it ideal for small and medium-sized shafts, precision gears, and collet chucks.
- SNCM415 and SNCM420: Mainly used for carburizing, suitable for large parts like spindles and spline shafts.
- SNCM616: Suitable for both carburized and tough steels, featuring high toughness and minimal dimensional changes during heat treatment. It’s used for strong gears, shafts, and casting molds but is challenging to machine.