Advanced workpiece materials

Group P

The ISO workpiece material classification group P includes mild and general steels.

The workpiece material classifications were decided based on material machinability.

However, the machinability of mild steel and general steel varies greatly. A common factor shared between the two materials is that they both generate continuous type chips that can easily damage the surface finish.


Machinability of workpiece materials

As the name explains, mild steel is soft, and welding can easily occur. However, the cutting resistance when machining mild steels is low, and this factor makes it necessary to choose tools with a priority on chip control and welding resistance.


In the meantime, chip control of general steel is not so troublesome, allowing for tool choice to be based mainly on tool life and machining efficiency.

When steel contains higher levels of carbon, it increases its heat treatable properties and is therefore harder and more adhesive. This type of steel generally, referred to as high carbon steel generates high temperatures during machining, necessitating heat resistant cutting tool grades. On the contrary, low carbon steel has the same inherent problems as mild steel.

Steel gears is an example of group P workpiece materials.