High Carbon Valve Steels and Alloys for Internal Combustion Engines
Valve steels and alloys for internal combustion engines are specialized high carbon steels and alloys designed to withstand temperatures up to 450 °C. These high-performance steels and alloys offer improved wear and fatigue resistance and improved reliability against high temperature valve failure. With improved tensile strength, they are more suitable for high stress applications like in diesel engines.
Valve steels and alloys, in accordance with the ISO 683-15:1992 and EN 10090-1998 standards, are classified into four groups according to their chemical composition:
• Group 1: contains additives of manganese, chrome and molybdenum and has a carbon content of 0.5-1.2%. It is suitable for temperatures up to 400 °C.
• Group 2: contains additives of chrome and molybdenum and has a carbon content of 0.6-1.3%. It is suitable for temperatures up to 420 °C.
• Group 3: contains additives of chrome, molybdenum and nickel with a carbon content of 0.75-1.3%. It is suitable for temperatures up to 440 °C.
• Group 4: contains additives of chrome and nickel with a carbon content of 0.7-1.4%. It is suitable for temperatures up to 450 °C.
These valve steels and alloys offer excellent hot workability and forging properties, making it easier to manufacture the valves. They are also available in various sizes and shapes.
The main advantage of using valve steels and alloys for internal combustion engines is their high resistance to mechanical and thermal fatigue, which allows them to perform better at higher temperatures and in higher speed environments. Additionally, they possess better wear resistance and corrosion resistance, as well as greater sensitivity to stress corrosion cracking when compared to regular carbon steel valves.
When selecting valve steels and alloys for internal combustion engines, it is important to pick materials that are strong enough to resist the harsh operating environment, such as high temperatures, high speed and extreme pressure. The chemical composition of the material should be carefully checked and the tolerances should meet the specific application requirements.
In summary, valve steels and alloys for internal combustion engines are specialized high-performance materials with improved tensile strength, wear resistance and fatigue resistance. They possess superior mechanical and thermal fatigue resistance and higher sensitivity to stress corrosion cracking than regular carbon steel valves. When selecting valve steels and alloys, the chemical composition and the tolerances should meet the specific application requirements.
