English Views: 0 Author: Eternal Tech Team Publish Time: 2026-10-09 Origin: Site
In manufacturing, molds are often called the "mother of industry," and mold steel is the core material that determines mold life, precision, production efficiency, and cost. Whether it is mobile phone housings, automotive lamp covers, medical containers, optical lenses, or stamped, die-cast, and forged parts, all rely on a mold with properly matched performance. Mold steel is not a single steel grade but a vast material family: some focus on corrosion resistance and mirror polishing, some emphasize high-temperature thermal fatigue resistance, some pursue high wear resistance and high toughness, and others are used for heavy-duty cutting or precision high-speed stamping. Different steels have different emphases in terms of hardness, toughness, wear resistance, corrosion resistance, polishability, hardenability, dimensional stability, and red hardness. Therefore, material selection cannot be based solely on "how hard it is," but should consider the mold's actual working conditions, molding materials, production volume requirements, and main failure modes.
This article starts from practical applications and systematically introduces the application scope of common mold steels, including plastic mold steel, hot work die steel, cold work die steel, high-speed tool steel, and powder metallurgy high-speed steel, to help you more quickly find the right type of steel for mold design, machining, procurement, and material selection.
It is a corrosion-resistant martensitic stainless steel plastic mold steel, produced by the electroslag remelting (ESR) process. It combines excellent corrosion resistance and superior mirror polishability with very high toughness and ductility. It also offers good wear resistance and dimensional stability, with a clean microstructure, and can achieve a mirror-grade polished finish. It is suitable for molds used in the food processing and animal feed industries, injection molds requiring high surface quality, and precision plastic products such as optical components and medical containers.
It is a high-chromium martensitic stainless steel plastic mold steel, refined by secondary refining plus electroslag remelting (ESR), with a clean and fine microstructure. It offers excellent corrosion resistance comparable to that of 420 stainless steel, along with good polishability, wear resistance, and machinability, and outstanding dimensional stability during quenching. It has excellent rust and acid resistance, and its corrosion resistance becomes even more reliable after quenching and mirror polishing. It is suitable for corrosive PVC and acetate injection molding environments, as well as plastic molds requiring high corrosion resistance and high polishing quality, such as those for optical components, medical products, and food industry products.
It is a precipitation-hardening, pre-hardened plastic mold steel, supplied at a hardness of 38–42 HRC. It offers high hardness and excellent wear resistance, making it suitable for plastic molding molds used in large-volume production. Its mirror polishability is extremely outstanding, enabling ultra-mirror finishing; it is also easy to texture/etch and has excellent weldability for overlay welding. Thanks to its age-hardening design, hardness is uniform from the core to the surface, and it still provides good machinability at the 40 HRC level. It is suitable for high-precision plastic molds, rubber molds, and plastic products requiring extremely high surface quality, such as lenses and ultra-clear exterior components.
It is a modified high-purity martensitic stainless steel plastic mold steel and a new-generation wear-resistant mirror mold steel launched by Fushun Special Steel, produced using military-grade steelmaking technology. It offers excellent corrosion resistance, polishability, and good wear resistance, along with very high toughness; after vacuum heat treatment, its hardness can reach HRC 52–58. It has a high degree of microstructural cleanliness and minimal heat-treatment deformation, making it suitable for precision mold machining. Its excellent rust resistance can greatly reduce mold maintenance costs. It is suitable for various plastic molds requiring high wear resistance, such as switches, sockets, and bakelite molds containing glass fiber and flame retardants, as well as for precision applications including optical product molds, automotive lamp molds, and LED lamp molds.
It is a pre-hardened chromium-nickel-molybdenum alloy plastic mold steel produced by a vacuum melting process, offering high steel cleanliness and excellent uniformity. It features excellent polishing and photo-etching performance, uniform hardness, and good machinability. It is supplied in the pre-hardened condition and can be directly machined for use. It is suitable for large, long-life plastic injection molds, such as molds for home appliances and computer housings, as well as molds for plastic products requiring high surface finish, blow molds, and sliders in plastic molds. It can also be used for compression molds, brake molds, and structural parts.
It is a pre-hardened plastic mold steel (3Cr2Mo) with good machinability and mirror polishing performance. Vacuum degassing refining treatment ensures a clean steel, making it suitable for plastic molds requiring polishing or texturing. It has uniform hardness, good polishing performance and photo-etching/texturing performance, good machinability, and good toughness at medium strength levels. Its supplied hardness is approximately 293–321 HB (31–34 HRC). It is widely used for large plastic molds and mold bases such as TV front shells, telephone sets, water dispensers, and vacuum cleaners, and is also used as a mold material for die-casting low-melting-point metals.
It is a premium stainless mold steel (Uddeholm Stavax ESR), produced by the electroslag remelting (ESR) process. It combines corrosion resistance and wear resistance with excellent polishability, good machinability, and quenching stability. With excellent corrosion and rust resistance, it is suitable for corrosive injection molding materials such as PVC and acetates, or for molds that must operate and be stored in humid environments. It offers outstanding mirror-polishing performance and is suitable for the production of optical components such as camera lenses and sunglass lenses, as well as long-life molds for medical containers, disposable tableware, and cutlery.
It is an electroslag remelted hot work die steel, specifically designed for the high tool hardness range of 51–57 HRC. It offers extremely high wear resistance and excellent toughness, along with good red hardness and resistance to temper softening. Due to its outstanding combination of wear resistance and toughness, it is also commonly used in cold work applications and plastic injection molds. It is suitable for smaller-sized components in die casting, such as die casting mold inserts, cores, punches, and ejector pins, and is also widely used for closed-die and open-die forging tools.
It is a chromium-molybdenum-vanadium alloy hot work die steel (ASSAB 8407 SUPREME), produced with special steelmaking technology and strict quality control. It features high purity and a fine microstructure, with better isotropy than conventional H13. It offers excellent thermal shock resistance and crack resistance, high high-temperature strength, and high toughness and ductility regardless of size, with isotropic properties and good machinability and polishability. Molds made of 8407 can be 1–2 HRC harder than those made of ordinary H13 without sacrificing toughness; the higher hardness helps slow the occurrence of thermal cracking. It is mainly used for aluminum, magnesium, and copper alloy die-casting molds, as well as forging dies and extrusion dies.
It is a chromium-molybdenum-vanadium high-performance hot work die steel (ASSAB 8418), an upgraded version of H13/SKD61/8407, produced by the electroslag remelting (ESR) process, with purity, isotropy, and thermal fatigue resistance significantly superior to ordinary H13. It offers excellent resistance to thermal fatigue cracking, thermal shock cracking, thermal wear, and plastic deformation, with high toughness and outstanding impact and chipping resistance. Under repeated high-temperature thermal cycling, its thermal cracking resistance is far superior to that of ordinary H13, greatly extending mold life. It is suitable for medium-to-large complex zinc, magnesium, aluminum, and titanium die-casting dies, as well as ultra-large forgings and integral dies for automotive structural parts.
It is a medium-alloy hot work die steel containing silicon, chromium, molybdenum, and vanadium, smelted in an electric furnace and then electroslag remelted (ESR), offering clean steel and better toughness. It features a balance of high-temperature strength and toughness, excellent thermal fatigue resistance, high hardenability, and good wear resistance, and is more resistant to molten-metal erosion than ordinary die steel. It is suitable for manufacturing extrusion dies, die-casting dies, hot forging dies, and hot shearing blades for aluminum, zinc, and copper alloys, and is also an ideal material for making ejector pins and ejector sleeves. In aluminum die-casting die applications, at a hardness of 40–46 HRC, its service life can reach 45,000–65,000 cycles.
It is a German-standard pressure-resistant hot work die steel (equivalent to H13). It offers excellent temper resistance and high-temperature toughness, strong thermal shock resistance, and good hardenability. It has a fine microstructure, good toughness and ductility, and excellent machinability and polishability. It can resist sudden temperature changes and thermal stress fatigue, and maintains stable dimensions after heat treatment with minimal deformation. It provides good machinability and polishing performance, along with high toughness and plasticity and excellent overall properties. It is widely used for aluminum, magnesium, and zinc die-casting dies, light and heavy metal extrusion dies, as well as steel mandrels, punches, shearing tools, and plastic molding tools.
It is an electroslag remelted hot work die steel (Cr-Mo-V type) with a uniform material structure. It offers excellent machinability and polishability. It has good high toughness and high ductility, and its wear resistance and through-hardening performance at both high and low temperatures are outstanding. It provides excellent toughness and ductility in all directions, high thermal fatigue resistance and wear resistance, and can be nitrided. It also has good dimensional stability and good hardenability, with better isotropy than conventionally melted steel. It is suitable for die-casting dies (cavity inserts, insert blocks, cores, spreader cones, nitrided ejector pins, and nitrided sleeves) as well as extrusion dies.
It is an air-hardening hot work die steel (4Cr5MoSiV1) and one of the most widely used grades among all hot work die steels. It has high hardenability and resistance to thermal cracking, excellent thermal fatigue resistance, and is not prone to thermal fatigue cracks; even when such cracks occur, they are relatively fine and short and do not readily propagate. It offers good heat resistance, good strength and hardness at elevated temperatures, high wear resistance and toughness, excellent comprehensive mechanical properties, and relatively high temper resistance. It is widely used for hot extrusion dies and mandrels, forging dies for die forging hammers, forging press dies, precision forging machine dies, and die-casting dies for aluminum, copper, and their alloys.
It is a chromium-molybdenum-vanadium alloy tool steel (Uddeholm Unimax), a high-hardness hot work tool steel that provides excellent wear resistance even during prolonged exposure to high temperatures. It offers excellent isotropic toughness and ductility, good wear resistance, and good machinability. It is suitable for long-life production molds, reinforced plastic molds, and compression molding molds, and is also a solution for high chipping resistance requirements in heavy-duty cold work tool applications such as heavy blanking, cold forging, and thread rolling. In molding processes with severe mold wear, such as long production cycles, reinforced plastic molding, and compression molding, it can improve mold durability and wear resistance.
It is a chromium-molybdenum-vanadium alloy hot work tool steel (Uddeholm Dievar). Through advanced development, production, and refining technology, it is manufactured as a die steel resistant to heat, cracking, thermal wear, and plastic deformation. It offers outstanding resistance to heat checking, gross cracking, thermal wear, and plastic deformation, and its thermal performance and thermal fatigue resistance are superior to those of AISI H13 and AISI H11. It has excellent toughness and hardenability, with outstanding resistance to heat checking. It is a preferred choice for die steels with high-performance requirements in die casting, forging, and extrusion, and is suitable for high-pressure die casting and other demanding hot work applications.
It is a Hitachi Metals hot work die steel (corresponding to JIS SKD61), smelted in an electric furnace and then electroslag remelted, resulting in cleaner steel and a uniform structure. It offers high toughness, wear resistance, and excellent resistance to heat erosion, with temper hardening characteristics, resistance to high-temperature softening, and good high-temperature fatigue resistance. It has good high-temperature strength, toughness, and high-temperature fatigue resistance, can withstand sudden temperature changes, and is suitable for long-term operation at high temperatures, with excellent machinability and polishing performance. It is used in general die-casting dies, zinc die-casting dies, low-pressure casting dies, high-hardness plastic molds, and hot forging punches, etc.
It is a new-type cold work die steel developed by modifying SKD11 (manufactured by Daido Steel), overcoming SKD11's shortcomings in high-temperature tempering hardness and toughness. After high-temperature tempering at 520–530°C, it can reach a high hardness of 62–63 HRC, exceeding SKD11 in strength and wear resistance, while its toughness is also significantly improved. It is suitable for precision stamping dies, precision blanking dies for wire-cut EDM machining, and stamping dies for various applications, as well as tools for the plastic deformation of difficult-to-machine materials, cold forging dies, deep drawing dies, and thread rolling dies.
It is a high-carbon, high-chromium alloy tool steel (BOHLER K110), a 12% chromium ledeburitic steel. After heat treatment, it offers very high hardness and wear resistance, strong hardenability, and good dimensional stability. The addition of molybdenum and vanadium improves machinability and hardenability. It has good resistance to temper softening and high compressive strength. It is suitable for high-precision, long-life cold work dies and thermosetting plastic molds, high-efficiency blanking dies, punching dies, and coining/embossing dies for thin sheets not exceeding 2 mm in thickness, as well as various scissors, insert blades, and woodworking blades.
It is a high-carbon, high-chromium alloy tool steel. After heat treatment, it offers very high hardness and wear resistance, strong hardenability, and good dimensional stability. It is suitable for making high-precision, long-life cold work dies and thermosetting plastic molds. This steel is easy to machine and is suitable for making sharp cutting edges, scissors, circular saws, cold or hot work trimming dies, screw threads, wire dies, milling cutters, stamping dies, etc. It can also be used for thermosetting resin molding molds. It is currently one of the most widely used cold work stamping die steels, offering good wear resistance and excellent toughness, with minimal quenching deformation.
It is a high-carbon, high-chromium air-hardening tool and die steel, belonging to ledeburitic steel. It offers high hardenability, high hardness, and high wear resistance, good high-temperature oxidation resistance, good rust resistance after quenching and polishing, and minimal heat-treatment deformation. It provides high hardness and high wear resistance, does not deform, and also has a certain degree of corrosion resistance. It is suitable for manufacturing various high-precision, long-life cold work dies, cutting tools, and measuring tools, such as complex-shaped punching dies, cold extrusion dies, thread rolling wheels, thread rolling dies, cold shearing blades, and precision gauges.
It is a 5% chromium air-hardening die steel (AISI A2 type), with excellent non-deforming properties and greater toughness than most cold work die steels. Its wear resistance lies between that of oil-hardening and high-carbon, high-chromium tool steels, but it offers higher toughness than both types. It is easy to machine, has good non-deforming characteristics and good hardenability, and can reach a hardness of 57–62 HRC after heat treatment. It is suitable for applications requiring a good combination of toughness, wear resistance, and machinability, including blanking dies, forming dies, punches and shear blades, drawing dies, curling dies, and embossing dies, etc.
It is an 8% chromium cold work die steel (BOHLER K340 ISODUR), produced by the electroslag remelting (ESR) process. Compared with conventional 12% chromium steel, it offers significantly better toughness, quenching performance, and higher resistance to adhesive wear. It features outstanding toughness, excellent compressive strength, and good machinability, with a uniform microstructure that reduces the risk of stress cracking during EDM. It is widely used in various fields of cold forming, such as blanking dies, punching and trimming dies, cold rolling rolls, cold extrusion dies, cold heading dies, and cold deep drawing dies, etc.
It is a high-carbon, high-chromium alloy tool steel (Hitachi Metals) and an improved version of SKD11. After heat treatment, it offers very high hardness and wear resistance, strong hardenability, and good dimensional stability. Due to a change in the amount of vanadium added, its machinability is significantly improved, and aging deformation as well as cracking and deformation during wire-cut EDM are suppressed. It has high toughness—twice that of SKD11—and its hardness after high-temperature tempering can reach above HRC 62. It is suitable for manufacturing precision stamping dies, extrusion dies, and drawing dies. It can also be used for measuring instruments, cutting tools, etc., as well as precision hardware mold forming and other molds requiring both high toughness and high wear resistance.
It is a high-carbon, high-chromium cold work die steel (ledeburitic steel), with hardenability, hardness after quenching and tempering, strength, and toughness all higher than those of Cr12. Workpieces with diameters of 300–400 mm or less can be fully through-hardened, with minimal quenching deformation. The addition of molybdenum and vanadium significantly improves the steel's hot working performance, impact toughness, and carbide distribution. It is used to manufacture various cold stamping dies and tools with larger cross-sections, complex shapes, and demanding working conditions, such as piercing dies, trimming dies, curling dies, deep drawing dies for steel sheet, circular saws, standard tools and gauges, and thread rolling dies, etc.
It is a tungsten-molybdenum high-speed tool steel (6-5-2 type), one of the most widely used and versatile high-speed steels. It offers high hardness and high strength, along with good toughness, high wear resistance, and high compressive strength, and can maintain stable cutting performance at temperatures below 600°C. It is suitable for manufacturing various wear-resistant and impact-resistant tools for heavy-duty cutting, high-grade stamping dies, screw dies, milling cutters, drill bits, etc. It is also used for various hot work and cold work dies, punches, cutting knives, slitting knives, and various roll tools, etc.
It is a tungsten-molybdenum series tough high-speed tool steel (Hitachi Metals), internationally used. Its carbide particles are fine and uniform, and it features high toughness, impact resistance, good cutting performance, and good hot plasticity. It offers good wear resistance, can resist high temperatures of 600°C without softening easily, and has good red hardness. After heat treatment and quenching, its hardness can reach 64 HRC, its wear resistance is twice that of high-chromium steel, and its toughness is 1.5 times higher. It is suitable for manufacturing various wear-resistant and impact-resistant tools for heavy-duty cutting, high-grade stamping dies, screw dies, milling cutters, drill bits, etc. It is also suitable for manufacturing long-life cold stamping dies and high-speed blanking dies.
It is a molybdenum-series high-speed tool steel (commonly known as 6542), offering the advantages of low carbide segregation and relatively high toughness. It has good hardness and wear resistance, but is prone to overheating, so the quenching heating temperature must be strictly controlled. It possesses excellent wear resistance and toughness, making it suitable for molds subjected to vibration and impact loads. It is mainly used for cold forging dies, fine blanking dies, powder compacting dies, shearing machine dies, plastic molds with added glass fiber, as well as deep drawing dies and piercing dies, etc. It can also be used as a cold work steel for punching, forming, and embossing dies.
It is an American molybdenum-series high-speed tool steel (W2Mo10Cr4Co8), with fine and uniformly distributed carbide particles, good toughness, high hardness, and good wear resistance. However, it has high sensitivity to decarburization and overheating, and its hot working and heat treatment ranges are relatively narrow. Its upper hardness limit can reach HRC 70; it has good red hardness, high high-temperature hardness, and is easy to grind. It is suitable for manufacturing various wear-resistant and impact-resistant tools for heavy-duty cutting, high-grade stamping dies, screw dies, and punches requiring relatively high toughness and complex shapes, etc. It is also used for high-toughness, precision, wear-resistant hardware cold stamping dies and cutting tools.
It is a powder metallurgy high-speed steel (tungsten-molybdenum type with high vanadium), manufactured by the powder metallurgy process. Based on the compositions of conventional high-speed steels such as M2 and SKH-9, its carbon and vanadium contents are increased, achieving an excellent balance among toughness, wear resistance, red hardness, and grindability. It offers good resistance to adhesive wear, chipping, and cracking, high compressive strength, as well as good hardenability and dimensional stability after heat treatment. It is particularly suitable for blanking and forming of thin workpiece materials, or for cases where die failure is caused by a combination of abrasive wear and adhesive wear. It is mainly used for precision high-speed stamping dies, cold work male and female dies, semiconductor IC molds, cold extrusion, cold forging, rack cutting, and powder compaction, etc.
It is a high-cobalt alloy powder metallurgy high-speed steel (ASSAB PM 60 SuperClean), with a total alloy content of nearly 40%, containing large amounts of cobalt and carbon, and is a high-performance powder metallurgy high-speed steel. It offers excellent wear resistance, excellent red hardness and temper resistance, and excellent compressive strength. It can still maintain high hardness and resistance to temper softening at high temperatures, is extremely wear-resistant, and typically achieves a hardness of HRC 67–70 after tempering. It is particularly suitable for cold work tools and dies requiring both maximum wear resistance and maximum compressive strength, such as heavy-duty cold work die punches and dies, electronic packaging material punching dies, precision trimming tools, carbide replacement dies, and forming tools for difficult-to-machine materials, etc.
