What are the primary factors influencing the machinability of materials?
1. Chemical composition: the higher the alloy composition of steel is, the more difficult it will be to process. When the carbon content increases, the metal cutting performance will decrease.
2. Structure of steel: different structures affect metal cutting performance, such as forging, casting, extrusion, rolling and machined, forging parts and casting have very difficult surfaces to be machined.
3. Hardness: hardness is an important factor influencing metal cutting performance. The general rule is that the harder steel is, the more difficult it will be to process.High speed steel (HSS) can be used for processing materials with a maximum hardness of 330-400 HB.High speed steel + TiN coating, machinable hardness up to 45 HRC materials;For materials with a hardness of 65-70 HRC, hard alloys, ceramics, metal ceramics, and cubic boron nitride (CBN) must be used.
4. Non-metallic inclusion: generally, it has adverse effects on tool life.For example, Al2O3 (alumina), which is a pure ceramic, has a strong abrasion.
5. Residual stress: residual stress can cause metal cutting performance problems, and it is often recommended to conduct stress release after rough machining.