Choosing materials is important. The chemical compositi […]
Choosing materials is important. The chemical composition of steel is important. The higher the alloy composition of steel, the harder it is to process. As the carbon content increases, the metal cutting performance decreases. The structure of steel is also very important for metal cutting performance. Different structures include: forged, cast, extruded, rolled, and machined. Forgings and castings have very difficult to machine surfaces.
Hardness is an important factor affecting metal cutting performance. The general rule is that the harder the steel, the harder it is to process. High-speed steel (HSS) can be used to process materials with a hardness of up to 330-400HB; high-speed steel + titanium nitride (TiN) coating can process materials with a hardness of up to 45HRC; and for materials with a hardness of 65-70HRC, you must Carbide, ceramic, cermet and cubic boron nitride (CBN) are used. Non-metallic impurities generally have an adverse effect on tool life. For example, Al2O3 (alumina), which is pure ceramic, has strong abrasiveness.
Forming method-you can choose from two basic material types.
A) Hot working tool steel, which can withstand relatively high temperatures during die casting, forging and extrusion.
B) Cold working tool steel, which is used for blanking and shearing, cold forming, cold extrusion, cold forging and powder press forming. Plastics-Some plastics produce corrosive by-products, such as PVC plastics. Factors such as condensation, corrosive gases, acids, cooling / heating, water or storage conditions caused by prolonged shutdown can also cause corrosion. In these cases, it is recommended to use stainless steel mold steel. Mold size-Large size molds often use pre-hardened steel. Solid hardened steel is often used for small size molds.