The machinability (machinability, machinability) of die steel is the same as the machinability, which refers to the degree of difficulty for metal materials to become qualified workpieces after being cut by cutting tools. So what are the factors that affect the machinability of die steel?

1.化学成分：钢的合金成分越高，就越难加工，当碳含量增加时，金属切削性能就下降。

1. Chemical composition: the higher the alloy composition of steel is, the more difficult it is to process. When the carbon content increases, the metal cutting performance will decline.

2.钢的结构：不同的结构影响金属切削性能，如锻造.铸造.挤压.轧制和已切削加工过的，锻件和铸件有非常难于加工的表面。

2. Steel structure: different structures affect metal cutting performance, such as forging, casting, extrusion, rolling and machined, forging and casting have very difficult machining surface.

3.硬度：硬度是影响金属切削性能的一个重要因素，一般规律是钢越硬，就越难加工。高速钢（HSS）可用于加工硬度为330-400HB的材料；高速钢+钛化氮（TiN）涂层，可加工硬度为45 HRC的材料；而对于硬度为65-70 HRC的材料，则必须使用硬质合金.陶瓷.金属陶瓷和立方氮化硼（CBN）。

3. Hardness: hardness is an important factor affecting metal cutting performance. The general rule is that the harder the steel is, the more difficult it is to machine. High speed steel (HSS) can be used to process materials with hardness up to 330-400hb; high speed steel + titanium nitride (TIN) coating can process materials with hardness up to 45 HRC; for materials with hardness of 65-70 HRC, cemented carbide, ceramics, cermet and cubic boron nitride (CBN) must be used.

4.非金属参杂：一般对刀具寿命有不良影响。例如Al2O3（氧化铝），它是纯陶瓷，有很强的磨蚀性。

4. Nonmetal impurity: generally, it has adverse effect on tool life. For example, Al2O3 (alumina), which is a pure ceramic, has strong abrasiveness.

5.残余应力：残余应力能引起金属切削性能问题，一般在粗加工后进行应力释放工序。

5. Residual stress: residual stress can cause metal cutting performance problems, and it is generally recommended to carry out the stress release process after rough machining.

铸铁的切削特性是什么？

What are the cutting characteristics of cast iron?

一般来说，铸铁的硬度和强度越高，金属切削性能越低，从刀片和刀具可预期的寿命越低，用于金属切削生产的铸铁其大部分类型的金属切削性能一般都很好。金属切削性能与结构有关，较硬的珠光体铸铁其加工难度也较大。片状石墨铸铁和可锻铸铁有优良的切削属性，而球墨铸铁相当不好。

Generally speaking, the higher the hardness and strength of cast iron, the lower the metal cutting performance, and the lower the life expectancy of blade and cutter. Most types of metal cutting performance of cast iron used in metal cutting production are generally very good. The cutting performance of metal is related to the structure, and the hard pearlite cast iron is difficult to process. Flake graphite cast iron and malleable cast iron have excellent cutting properties, while nodular cast iron is rather poor.

一般对加工铸铁所要求的典型刀具属性为：

Generally, the typical tool properties required for processing cast iron are as follows:

高热硬度和化学稳定性，但也与工序.工件和切削条件有关；要求切削刃有韧性.耐热疲劳磨损和刃口强度。切削铸铁的满意程度取决于切削刃的磨损如何发展：快速变钝意味着产生热裂纹和缺口而使切削刃过早断裂，工件破损，表面质量差，过大的波纹度等。正常的后刀面磨损，保持平衡和锋利的切削刃正是一般需要努力做到的。

High thermal hardness and chemical stability, but also related to process, workpiece and cutting conditions; the cutting edge is required to have toughness, thermal fatigue wear and edge strength. The satisfaction of cutting cast iron depends on how the wear of the cutting edge develops: rapid blunting means hot cracks and notches, resulting in premature fracture of the cutting edge, workpiece damage, poor surface quality, excessive waviness, etc. Normal flank wear, maintaining balance and sharp cutting edge is the general need to strive to achieve.