Differences between HSS, HSSE and HSSE-PM

Do you know this? Frayed drill holes? Dull drill bits? Unfortunately, these are consequences of the wrong choice of a drill bit. HSS, HSSE, and HSSE-PM are the abbreviations for different types of tool steels used in the production of drill bits and screw taps. Here is a brief explanation of the differences:

  1. HSS (High-Speed Steel): HSS is a high-alloy tool steel commonly used for drills, twist drill bits, screw taps or thread cutting dies. HSS has up to four times the cutting speed of commercial tool steel. It features a good combination of hardness, wear resistance and toughness. The compressive strength at room temperature is about 2,000 to 3,000 N/mm². HSS retains its hardness even at higher temperatures up to about 600 °C, so that cutting speeds of 80 m/min are possible in steel. In comparison, ordinary tool steel, also known as cold work steel, loses its hardness from about 200 °C, and cutting speeds in steel are limited to 5 m/min. Coatings can be used to increase the wear resistance and service life of threading tools. HSS is well suited for general applications and offers good performance in low to medium stress conditions.
  2. HSSE (High-Speed Steel with Cobalt): HSSE, or HSS-E, is a further development of HSS in which 5% or 8% cobalt (Co) is added as an alloying element. This improves the heat resistance and wear resistance of the high-speed steel, this also leads to a longer tool life time. HSSE drills are particularly well suited for demanding applications with higher temperatures and harder materials.
  3. HSSE-PM (High-Speed Steel with Cobalt and Powder Metallurgy): HSSE-PM is a further development of HSSE. In the production of this special tool steel, cobalt is added and the powder metallurgical process is used. This further improves toughness and wear resistance and achieves outstanding tool life. HSSE-PM screw taps are particularly suitable for demanding applications with high stress and difficult materials.
Bernd the bear with various threading tools

In summary, the higher the cobalt content and the more advanced the manufacturing process, the more resistant and durable the tool steel. Therefore, when selecting the appropriate drill bit or screw tap, it is important to carefully consider the specific requirements of the application and the material to be machined. HSS is well suited for general applications, while HSSE and HSSE-PM offer better performance in more demanding environments. Individual needs and requirements should be carefully considered to make the best choice and achieve optimum results in your tapping and drilling operations.