What are the most important factors affecting the machinability of mould steel materials?

It is often said that good materials cost a lot of money in knives and knives, which speaks to the fact that the machinability of the die steel material is affected by the material itself, while the material properties are mainly composed of its chemical composition, hardness, etc. What are the most important factors affecting the machinability of mould steel materials?

1. The chemical composition of the steel

The chemical composition of the steel is important. The higher the alloy composition of the steel, the more difficult it is to machine. When the carbon content increases, the metal cutting properties decrease.

2. The structure of the steel

The structure of the steel is also very important for the metal cutting properties. The different structures include: cast, foundry, extruded, rolled and machined. Forgings and castings have very difficult to machine surfaces.

3. Hardness of steel

Hardness is an important factor affecting the cutting performance of metals. The general rule is that the harder the steel, the more difficult it is to machine. High speed steel (HSS) can be used to machine materials with a hardness of up to 330-400 HB; HSS titanium nitride (TiN) coated, can machine materials with a hardness of up to 45 HRC; and for materials with a hardness of 65-70 HRC, carbide, ceramic, cermet and cubic boron nitride (CBN) must be used.

Non-metallic inclusions generally have an adverse effect on tool life. Al2O3 (aluminium oxide), for example, which is pure ceramic, is highly abrasive.

4. Residual stresses

The last one is residual stresses, which can cause metal cutting performance problems. It is generally recommended to carry out a stress relief process after rough machining.