Which of the following materials is not suitable for wire drawing dies?

Wire drawing dies need to withstand high pressure, high-speed friction and complex chemical environment, so the material hardness, wear resistance, strength and corrosion resistance are extremely high.

The following materials are usually not suitable due to performance defects: ordinary carbon steel (Q235) has low hardness (HRC≤20) and is easy to corrode, aluminum alloy softens at high temperature and has insufficient strength, ordinary cast iron is brittle and has poor wear resistance, low-hardness tool steel (such as T8 steel) has a hardness of only HRC55-60 and is easy to temper at high temperature, unreinforced ceramics (such as pure alumina) have a high risk of brittle fracture, and plastics (such as polytetrafluoroethylene) have insufficient heat and pressure resistance. These materials are prone to wear, deformation, cracking or adhesion during the drawing process, resulting in short die life and affecting wire quality.

Tungsten carbide, cubic boron nitride (CBN), and diamond-coated tool steel are usually selected as materials for wire drawing dies to ensure die life and wire surface quality.