Tool steel is the backbone of many industrial applications, relied upon for its exceptional durability, hardness, and resistance to wear and abrasion. Within the realm of tool steel, there exist various grades, each engineered to excel in specific tasks and environments. Understanding the nuances of these grades is crucial for selecting the right material for the job at hand. In this guide, we delve into the six primary grades of tool steel, elucidating their properties and applications.

1. W1: Often referred to as water-hardening tool steel, W1 is one of the simplest and least expensive grades available. It possesses excellent toughness and wear resistance, making it suitable for applications such as chisels, punches, and woodworking tools. However, W1 steel lacks the high hardness and edge retention of other grades, necessitating frequent re-sharpening.

2. O1: Oil-hardening tool steel, or O1, is renowned for its superior machinability and dimensional stability. It exhibits excellent wear resistance and can be easily heat-treated to achieve high hardness levels. O1 steel finds widespread use in tool and die making, blanking, forming, and cutting applications.

3. A2: Air-hardening tool steel, A2, boasts exceptional toughness and resistance to deformation at elevated temperatures. It is characterized by its high abrasion resistance and dimensional stability during heat treatment. A2 steel is commonly employed in applications such as blanking dies, forming dies, and gauges requiring high wear resistance.

4. D2: D2 tool steel is revered for its high carbon and chromium content, endowing it with excellent wear resistance and edge retention. It offers superior hardness and abrasion resistance compared to many other grades, making it ideal for applications such as cold forming dies, blanking dies, and thread rolling dies.

5. S7: S7 tool steel is a shock-resistant grade renowned for its exceptional toughness and impact resistance, even at low temperatures. It features high hardenability and good dimensional stability during heat treatment. S7 steel is commonly utilized in applications subjected to high impact and stress, including hammer and chisel heads, shear blades, and pneumatic tools.

6. M2: M2 tool steel, also known as high-speed steel (HSS), is revered for its unparalleled combination of hardness, wear resistance, and heat resistance. It can maintain its cutting edge even at high temperatures, making it ideal for applications such as drills, taps, reamers, and milling cutters requiring high cutting speeds and temperatures.

Each grade of tool steel possesses unique properties that cater to specific industrial requirements. The selection of the appropriate grade depends on factors such as the intended application, desired hardness, wear resistance, and machinability. By understanding the characteristics of each grade, manufacturers and engineers can make informed decisions to optimize performance and productivity in their respective fields.