What material is usually preferred for high-strength applications in machining?

Tool steel is typically preferred for high-strength applications in machining due to its exceptional hardness and wear resistance. This type of steel is specifically alloyed to enhance its mechanical properties, making it ideal for cutting tools, dies, and molds that require durability and stability under high-stress conditions. The unique combination of carbon and other elements within tool steel allows it to maintain sharp cutting edges and withstand high temperatures without losing its strength.

In contrast, aluminum and plastic, while useful in various applications, do not possess the same level of hardness or strength when subjected to demanding machining scenarios. Aluminum is lightweight and corrosion-resistant, making it suitable for applications where weight is a concern, but it lacks the toughness needed for high-strength tasks. Plastic is versatile and can be molded into complex shapes, but it is generally not used in high-stress environments due to its tendency to deform under pressure. Copper, on the other hand, is valued for its excellent conductivity and machinability but falls short in strength compared to tool steel. Therefore, in the context of high-strength requirements in machining, tool steel stands out as the most suitable material choice.