8407 is a high‑purity chromium‑molybdenum‑vanadium hot‑work die steel developed by ASSAB, corresponding to domestic H13 and electroslag remelting SKD61. With excellent high temperature resistance, high wear resistance, high toughness, high polishability and thermal fatigue resistance, it occupies a high‑end position in plastic mold applications, especially suitable for scenarios requiring long service life, stable molding and high surface quality. Its pure material and uniform structure can reach HRC 48–52 after vacuum quenching and high‑temperature tempering, balancing wear resistance and toughness, which can effectively solve the problems of easy wear, cracking and poor polishing effect of ordinary steels.
Core Applicable Plastic Types8407 performs best with high‑abrasion, high‑mold‑temperature and high‑viscosity engineering plastics, especially glass‑fiber reinforced grades. It is widely used for PA6, PA66 with 30%–50% glass fiber, PBT+GF, PET+GF. These plastics have strong glass fiber particle erosion, high molding temperature (80–120°C) and fast injection speed. 8407’s high hardness and wear resistance can greatly extend mold life and reduce mold repair times. It is also ideal for high‑temperature plastics such as PPS, LCP and PEEK, which require stable performance under long‑term high heat (molding temperature 300–400°C).
For optical‑grade materials including PC and PMMA, 8407 provides excellent polishability up to #10000 for mirror finish, producing transparent products without pits and flow marks. It also works well for some corrosive or abrasive materials such as PVC and POM after nitriding or PVD coating. In addition, 8407 is suitable for thermoset plastic molds such as BMC and DMC, which have high molding temperature, high pressure and strong wear.
Applicable Mold Structures and Components8407 is mainly used for core, cavity and insert parts that bear high stress, are easy to wear and contact high temperature. It is not necessary to use 8407 for the entire mold. Core molding parts with large batches, high cycles, high wear and high mold temperature prefer 8407 to ensure molding accuracy and mold life. Gate bushes, sprue bushes and diverters, which suffer from high‑speed melt erosion for a long time, can benefit from 8407’s erosion resistance and thermal fatigue resistance to extend service life. Slides, lifters and inserts, which are moving parts with frequent friction and concentrated local stress, can take advantage of 8407’s balanced toughness and wear resistance to avoid chipping and scratching.
Unsupported Application ScenariosAlthough 8407 has excellent performance, it is not suitable for all plastic molds. For small‑batch, low‑wear, low‑temperature plastic molds such as PP, PE and ABS, pre‑hardened steels such as 718H, NAK80 and S136H can meet the requirements, and 8407 is not cost‑effective. For mold structures with ultra‑long thin core pulling, extremely thin wall thickness and one‑sided severe impact, 8407’s toughness is not as good as that of high‑toughness steels such as LG and modified DC53, which is prone to fracture. For strong corrosive scenarios such as long‑term production of strong acidic PVC and chlorine‑containing flame retardants, 8407’s corrosion resistance is not as good as that of stainless steels such as S136 and 420, so special corrosion‑resistant steels are recommended.
Typical Industry Applications and Material Selection Points8407 is widely used in high‑end fields such as automotive, electronics, industrial machinery and medical. In the automotive industry, it is used for molds of engine parts, vehicle lamps, interior structural parts and connectors. In the electronic and electrical industry, it is used for molds of precision connectors, coil frames and optical components. In the industrial machinery industry, it is used for molds of gears, bearing seats and valve parts. In the medical industry, it is used for molds of some high‑requirement transparent parts and wear‑resistant structural parts. For material selection, the common hardness of plastic molds is HRC 48–52, balancing wear resistance, toughness and polishability. Vacuum quenching and high‑temperature tempering must be carried out to ensure dimensional stability and uniform structure. Nitriding or PVD coating can be done according to needs to further improve wear resistance, anti‑sticking and corrosion resistance.
