▌ The methods to change the properties of steel are mainly as follows: 1. Alloy composition carbon: C increases the hardness of the quenching structure; form carbides to improve wear resistance; reduce toughness; reduce weldability Cr: Cr increases the hardness of steel to form h

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▌ Definition of steel:

Steel refers to an iron-carbon alloy with a carbon content of 0.0218% to 2.11%. Adding Cr, Mo, V, Ni and other alloy components to ordinary steels can obtain alloy steel . Our mold steels are all alloy steels.

▌ The methods to change the properties of steel are mainly as follows:

1. Alloy composition

Carbon: C

  • increases the hardness of the quenched structure;
  • forms carbides and improves wear resistance;
  • reduces toughness;
  • reduces weldability

Chromium: Cr

  • increases the hardness of steel to form hard and stable chromium carbide, thereby improving wear resistance;
  • can improve the hardness of steel ;
  • When the Cr content exceeds 12%, It has corrosion resistance and provides good polishing and rotational properties

Molybdenum: Mo

  • Mo is a strong carbide-forming element, improving wear resistance;
  • Mo>0.5% can inhibit tempering brittleness caused by other alloy elements;
  • provides red hardness and thermal strength;
  • improves hardenability and tempering stability

Vanadium: V

  • can form high hardness carbides and improve wear resistance;
  • refines the grains of steel, reduces superheating sensitivity, improves the strength, toughness and tempering stability of steel

nickel: Ni

  • Ni can improve the hardenability of steel;
  • Ni can refine the grains

sulfur (S)

  • often exists in steel in the form of MnS, which deteriorates the continuity of the cutting matrix, deteriorates the toughness, corrosion resistance, polishing, discharge processability, and corrosion properties of the material, and can improve the cutting ability of the material.

2. Smelting process

  • Ordinary steelmaking process

  • Electroslag remelting (ESR)
  • Place the crude steel billet in an electric slag furnace, and a strong current is sent to the electric furnace to generate a very high temperature, so that the crude steel billet melts into steel water, the steel water flows through the electric slag, and impurities are filtered and adsorbed by the electric slag, thereby achieving the purification effect. The overall remelting speed is fast, but some very fine impurities are not removed.

  • Vacuum arc remelting (VAR)
  • is in a vacuum furnace, and a strong current is passed on the steel blast. The bottom of the steel blast begins to melt, and the impurities vaporize into gas and are drawn away, thereby increasing the purity of the steel. Moreover, it solidifies drop by drop, the solidification rate is very fast and the tissue becomes very dense. The characteristics are that the impurities are thoroughly removed, but the overall remelting speed is slow.

3. Heat treatment

Heat treatment of steel refers to the process of changing the performance of steel by heating and cooling by controlling the heating temperature, insulation time and cooling speed of the steel to meet the processing or use requirements. The main heat treatment processes include: annealing, quenching, tempering, .

▌ mold steel classified by use

1. cold work mold steel

cold work mold steel is mainly used to make molds that press molds for workpieces in cold state. Such as cold punching molds, cold stamping molds, cold drawing deep drawing molds, imprinting molds, cold extrusion molds, thread pressing molds and powder pressing molds, etc. The range of cold work mold steel is very wide, from various carbon tool steels, alloy tool steels, high-speed tool steels to powder high-speed tool steels and powder high-alloy tool steels.

2. Hot working mold steel

Hot working mold steel is mainly used to manufacture molds that pressure processing workpieces under high temperature states. Such as hot forging molds, hot extrusion molds, die casting molds, hot upset forging molds, etc. Commonly used hot-working mold steels include: alloy mold steels with medium and high carbon content added with alloy elements such as Cr, W, Mo, V; for hot-working mold steels with special requirements, they are sometimes made of high alloy austenite heat-resistant mold steel.

3. Plastic mold Steel

Due to the many varieties of plastics, the requirements for plastic products are also very different, and various performance requirements are also put forward for the materials used to make plastic molds. Therefore, many developed industrial countries have formed a wide range of steel series for plastic molds.Including carbon structural steel, carburized plastic mold steel, pre-hardened plastic mold steel, aging hardened plastic mold steel, corrosion-resistant plastic mold steel, easy-cut plastic mold steel, overall hardened plastic mold steel, martensite aging steel, and plastic mold steel for mirror polishing, etc.

Die molds into five levels according to their lifespan. Requirements for steel:

Die molds are generally divided into five levels according to their service lifespan. Level 1 is more than one million times, Level 2 is 500,000-1 million times, Level 3 is 300,000-500,000 times, Level 4 is 100,000-300,000 times, and Level 5 is less than 100,000 times.

Both first and second-level molds require steel that can be heat-treated and hardness around HRC50, otherwise it will be easy to wear and the injection molded products are prone to exceed the difference. Therefore, the selected steel must have good heat treatment performance and good cutting performance under high hardness. Of course, there are other considerations.

usually uses 8407, S136, 20, H13 in the United States, 2316, 2344, 083 in Europe, or SKD61, DC53 in Japan (original hardware mold material, used in special circumstances). Plastics with strong corrosiveness are generally selected as S136, 2316, 420 and other steels. In addition to S136, 2316, 420 and weak corrosiveness, there are also SKD61, NAK80, PAK90, and 718M. The appearance requirements of the product also have a great impact on the selection of mold materials. Products with transparent parts and surfaces that require mirror surfaces, the available materials include S136, 2316, 718S, NAK80, PAK90, 420. The molds with extremely high transparency should be S136, followed by 420.

The third-level mold uses many pre-hardened materials, and the grades are S136H, 2316H, 718H, and 083H, with hardness HB270-340.

Level 4 and 5 molds use P20, 718, 738, 618, 2311, 2711. For molds with very low requirements, S50C, 45# steel may be used, that is, the cavity is directly made on the mold embryo.

▌ Steel codes of various countries

1. American standard AISI

Code:

P1-P19: LowCarbon Steel

P20-P39: Low Carbon, High Alloy Steel (Plastic molded steel)

2XX,3XX,4XX,6XX: Stainless Steel (Stainless Steel)

H1-H19: Chromium base (chromium-based-hot steel)

Wx: Water Hardening Steel

Sx: Shock Resisting Steel

Ox: OilHardening Steel (oil steel)

Ax: AirHardening Steel

Dx: High Carbon, High Chromium Steel (chromium steel)

Mx: Molybdenum base (H.S.S.- high-speed steel )

2. German standard DIN

Code:

1.2738: Low carbon, high alloy (P20 - Plastic mold steel)

1.2311: Low carbon, high alloy (P20 - Plastic molded steel)

1.2312: Lowcarbon, high alloy, free Machine (P20-easy cutting)

1.2083: StainlessSteel (420-acid-resistant steel)

1.2316: High performance stainless steel (420-high-acid-resistant steel)

1.2343: Chromiumbase (chromium-based-H11-hot-working steel)

1.2344: Chromiumbase (chromium-based-H13-hot-working steel)

1.2510: Lowalloy steel (O1-oil steel)

1.2379: Highcarbon, high chromium steel (D2 – chromium steel)

3. Japanese standard JIS

Code:

SxxC: Plain Carbon steel (Huang Brand - S55C)

SUSxx: Stainless Steel (Acne-anti-steel-420)

SCrx: Chromium Steel

SCMx: Chromium Molybdenum Steel (P20)

SKx: Carbon Tool Steel

SKSx: Low Alloy Steel (O1)

SKD11: MediumHigh Alloy Steel (Chrom Steel-D2)

SKD6: MediumHigh Alloy Steel (MediumHigh Alloy Steel-H11)

SKD61: MediumHigh Alloy Steel (MediumHigh Alloy Steel-H13)

SKHxx: High Speed ​​Steel (High Speed ​​Steel-M 2)

SUMx: Free Cutting Steel (Easy Cutting Steel)

SUJx: Bearing Steel

▌ Common imported mold steel and its parameters and performance

Sweden Yishengbai STAVAXESR-S136 — High wear resistance, corrosion resistance, pre-hardened mirror steel

  • factory status: HB215
  • equivalent Buderus standard: 2316
  • equivalent Bailu Bohler standard: M310
  • equivalent Hitachi hitachi standard: HPM38
  • equivalent Datong DAIDO standard: PAK90
  • wear resistance: ★★★☆☆
  • Toughness: ★★★☆☆
  • Dimensional stability: ★★★☆☆
  • Processability: ★★★☆☆
  • Polishing: ★★★★★★★★
  • Corrosion resistance: ★★★★☆
  • Product description: For advanced non-embroidered tool steel . Excellent corrosion resistance, polishing, wear resistance and mechanical processing. Electric spark processing can achieve ultra-mirror processing effect and high-quality surface, and have excellent stability during quenching. After the mold is used for a long time, the surface of the mold hole remains smooth. The mold does not require special protection when operating or storing in humid environments. Recommended for injection molds and corrosive plastic molds with high polishing requirements.

Sweden One Win Hundred 8402 — High-quality hot work tool steel

  • Factory status: HB 185
  • Quite Buderus standard: 2344
  • Quite Bohler standard: W302
  • Quite Hitachi Hitachi standard: DAC
  • Quite Dasame DAIDO standard: DHA1
  • Wear resistance: ★★☆☆☆
  • Toughness: ★★★☆☆
  • Hardenability: ★★★☆☆
  • Processing: ★★★☆☆
  • Product Description: High and low temperatures have good wear resistance, excellent toughness and ductility, stable and excellent processability and polishing properties, excellent high temperature strength and thermal fatigue resistance, excellent hardenability, and very small heat treatment dimensional deformation. Used for metal hot forging molds, aluminum extrusion molds, plastic molds, aluminum die casting molds, etc.

Sweden One Hundred 8407 — Advanced hot work tool steel

  • Factory status: HB 185
  • Quite Buderus standard: 2344ESR
  • Quite Hitachi Hitachi standard: DAC
  • Quite Dasame DAIDO standard: DHA1
  • Wear resistance: ★★★☆☆
  • Toughness: ★★★☆☆
  • Hardenability: ★★★☆☆
  • Processing: ★★★★☆
  • Product description : It is a chromium, molybdenum, vanadium alloy tool steel. It uses special steelmaking technology and strict quality control to obtain high purity and fine structure. The isotropicity (isotropy) of 8407 is better than that of the general traditional refining system H13. This is more valuable for the anti-mechanical fatigue and thermal stress fatigue properties of the mold, such as die-casting molds, forging molds and extrusion molds. Therefore, the hardness of the mold using 8407 can be increased by 1-2 HRC compared to ordinary H13 without sacrificing toughness. High hardness can slow down the occurrence of thermal cracks and improve mold life. Used for various metal die casting molds, extrusion molds, and high-quality plastic molds.

Sweden Yishengbai ASP23 — High wear resistance, high toughness powder high speed steel

  • Factory status: HB 260
  • is equivalent to Hitachi Hitachi Standard: HAP10
  • Wear resistance: ★★★★☆
  • Toughness: ★★★☆☆
  • Temperature stability: ★★★☆☆
  • Processability: ★★★☆☆
  • Product description: It is chromium molybdenum vanadium powder steel, with high wear resistance (anti-wear particle wear), high compressive strength, very good hardenability, good toughness, good dimensional stability of heat treatment, and good tempering softening resistance. ASP-23 is particularly suitable for the cutting and forming of thin processed materials, or mold failure is due to the wear and adhesion of mixed abrasive particles, or the wear of knowledge abrasive particles, and the risk of plastic deformation of the surface is also high. For example, cutting of medium-carbon steel or high-carbon steel, cutting hardened steel plates or cold-rolled steel strips, plastic molds containing glass fibers.

Sweden Yishengbai XW-42 — Advanced high wear-resistant cold work tool steel

  • factory status: HB210
  • is quite Buderus Buderus standard: 2379
  • is quite Bohler standard: K110
  • is quite Hitachi hitachi standard: SLD
  • is quite the same as DAIDO standard: DC11
  • wear resistance: ★★★☆☆
  • toughness: ★★★☆☆
  • dimension stability: ★★★☆☆
  • processability: ★★★☆☆
  • Product Description: It is a high-carbon and high-chromium alloy tool steel containing molybdenum and vanadium. It has both wear resistance and toughness, and has excellent quenching properties, which are often recommended as molds that require good wear resistance and appropriate toughness (impact resistance). For example: precision hardware molds, semiconductor molds, precision parts, etc.

Sweden One Win 1 718HH — High polishing pre-hard precision plastic mold steel

  • Factory status: Pre-hard HB 330-370
  • Quite Buderus standard: 2711
  • Wear resistance: ★★★☆☆
  • Toughness: ★★★☆☆
  • Processability: ★★★☆☆
  • Polishing: ★★★★☆☆
  • Corrosion resistance: ★★★☆☆
  • Product description : It is vacuum-smelted chromium-nickel-molybdenum alloy steel, and the improved pre-hardened plastic mold steel. It has been hardened and tempered before leaving the factory. There is no risk of quenching and cracking and heat treatment deformation. There is no need for heat treatment. Nitriding and flame hardening can be applied to improve the surface hardness and wear resistance of the mold. Very excellent polishing performance and improved wear resistance. Used for injection molds and extrusion molds of thermoplastic materials, plastic product molds, blow molds, forming molds, structural parts, and shafts with high surface finish.

Sweden Yishengbai VIKING — High wear resistance, high toughness cold work tool steel

  • Factory status: HB225
  • Wear resistance: ★★★☆☆
  • Toughness: ★★★★☆
  • Temperature stability: ★★★☆☆
  • Processing: ★★★☆
  • Product description: Good heat treatment dimensional stability, good machining, combining excellent toughness and good wear resistance. It is used in fine punching dies, edge cutting dies, deep drawing dies, cold forging dies, etc.

Japan Datong NAK80 — Pre-hard mirror precision plastic mold steel

  • Factory status: HRC37-43
  • is equivalent to Hitachi hitachi Standard: HPM50
  • wear resistance: ★★★☆☆
  • toughness: ★★★☆☆
  • processability: ★★★☆☆
  • polishing: ★★★★☆
  • corrosion resistance: ★★★☆☆
  • product description: pre-hardened steel (36-43 HRC), which can be processed directly without heat treatment; the hardness of the surface and center is relatively uniform, and the machining is good; the discharge processability is good, and the grinding after discharge process is very easy, because the surface hardness after discharge process is uniform and the white layer is low; the mirror polishing is good; the welding is good; the corrosion is good; the dimensions are stable, and suitable for precision parts and large-scale production. Due to its chemical composition, this material is highly brittle and is prone to cracking in places with relatively concentrated processing stress when used in more complex molds. It has high thermal sensitivity. It must be preheated during welding, heat insulation, heat and stress removal treatment after welding, otherwise there will be a risk of welding failure. It should be noted that when the treatment temperature exceeds 520°C, the size will be changed.

Japan Datong DC53 — High hardness and high toughness cold work tool steel

  • Factory status: HB255
  • is quite Hitachi hitachi Standard: SLD8
  • is quite a win-win ASSAB standard: ASSAB88
  • wear resistance: ★★☆☆☆
  • Toughness: ★★★★☆☆
  • Dimensional stability: ★★☆☆
  • Processability: ★★★☆☆
  • Polishing: ★★★☆☆
  • Product Description: Datong Steel DC53 is improved on the basis of SKD11. The hardness after heat treatment is higher than SKD11. After high temperature (520-530℃) is tempered, it can reach 62-63HRC high hardness, exceeding SKD11 in terms of strength, and its toughness is twice that of SKD11. Toughness is more prominent in cold work mold steel, so cracks and cracks are rarely seen when manufactured with DC53, which greatly improves the service life. The residual stress after wire cutting process reduces the residual stress by high temperature tempering. Therefore, cracks and deformations after online cutting and processing of large molds and molds that require precision are suppressed. The machinability exceeds SDK11. DC53 has better machinability than SDK11. Therefore, the use of DC53 can increase the mold life and reduce the processing process.

Japan Datong NAK55 — High pre-hard high performance precision mold steel

  • Factory status: HRC37-43
  • Wear resistance: ★★★☆☆
  • Toughness: ★★★☆☆
  • Processing: ★★★☆☆
  • Polishing: ★★★★☆
  • Product Description: Pre-hardened steel, no heat treatment required, suitable for mirror polishing processing pre-hardened steel. It is mainly used in mirror polishing molds, with excellent polishing properties, machinability and erosion properties.

Japan Datong S-STAR — Pre-hardened high polish corrosion resistant plastic steel

  • Factory status: HRC30-34
  • is quite Buderus Buderus standard: X40Cr13
  • is quite Hitachi hitachi standard: HPM38
  • is quite a win-win ASSAB standard: S136
  • wear resistance: ★★★☆☆
  • Dimensional stability: ★★★★☆
  • processability: ★★★★☆
  • polishing: ★★★★★★★☆
  • polishing: ★★★★★★★★★★
  • corrosion resistance: ★★★★☆
  • Product Description: Pre-hard corrosion-resistant high polishing stainless steel, high polishing elasticity, good corrosion resistance, good wear resistance, good dimensional stability, suitable for molds that require high mirror, high wear resistance and corrosion resistance. For example: rubber molds, VCD video disc molds, cosmetic containers, and medical equipment tools, etc.

Japan Datong DHA1 — High performance hot work tool steel JIS SKD61

  • Factory status: HB229
  • Quite Buderus standard: 2344
  • Quite Bohler standard: W302
  • Quite Hitachi Hitachi standard: DAC
  • Quite ASSAB standard: 8402
  • Wear resistance: ★★★☆☆
  • Toughness: ★★★☆☆
  • Red hardness: ★★★☆☆
  • Dimensional stability: ★★★☆☆
  • Processability: ★★★☆☆
  • Polishing: ★★☆☆☆
  • Product Description: Datong Steel DHA1 is widely used in aluminum and magnesium die-casting molds. It has good machinability and heat resistance.It is a general thermal mold steel. DHA1 is used in aluminum-magnesium die-casting molds, die-casting molds and related parts, hot stamping molds, hot extrusion molds, and hot shear blades.

— High hardness, high wear resistance, high chromium tool steel JIS SKD11

  • Factory status: HB255
  • Quite Buderus standard: 2379
  • Quite Bohler standard: K110
  • Quite Hitachi Hitachi standard: SLD
  • Quite ASSAB standard: XW-42
  • Wear resistance: ★★★☆☆
  • Toughness: ★★★☆☆
  • Dimensional stability: ★★★☆☆
  • Processability: ★★★☆☆
  • Product Description: Long life, high wear resistance, high toughness, impact resistance, heat treatment is not easy to deform, and the structure is subtle. It is mainly used in punching dies, precision hardware stamping dies, cold work forming dies, cold drawing dies, forming rolls, and punches.

Japanese Hitachi Metal HPM1 — Advanced pre-hard mold steel

  • Brand: Japanese Hitachi Metal
  • Factory status: HRC37-42
  • Very same DAIDO standard: NAK55
  • Wear resistance: ★★★☆☆
  • Toughness: ★★★☆☆
  • Processing: ★★★☆☆
  • Polishing: ★★★★☆☆
  • Corrosion resistance: ★★★☆☆
  • Product description: Advanced pre-hard plastic mold steel with hardness up to HCR37-42℃, no need for heat treatment. Large-piece molds are made of special dissolution and good machining (the best when HRC40) and have balanced hardness and machining properties inside and outside, with good machining properties, good polishing properties, no heat treatment, good machining properties, good corrosion resistance, and excellent polishing properties. It is mainly used in precision rubber molds, high-strength mold plates, etc.

Japanese Hitachi Metal SLD — High wear-resistant high chromium cold work tool steel JIS SKD11

  • Brand: Japan Hitachi Metal
  • Factory status: HB210
  • Quite Buderus Buderus standard: 2379
  • Quite Bohler standard: K110
  • Quite Dashi DAIDO standard: DC11
  • Quite ASSAB standard: XW-42
  • wear resistance: ★★★☆☆
  • Toughness: ★★★☆☆
  • Dimensional stability: ★★★★☆
  • Processability: ★★★☆☆
  • Product Description: A wide range of general-purpose cold processing tool steel. It has extremely high wear resistance, high compressive strength, relatively good toughness, good quenching performance, and small deformation of heat treatment. In recent years, with the application of isotropy, the performance of SLD has been further improved, and the use effect is significantly better than other SKD11 type mold materials. Used for stamping, blanking, shearing, stretching, bending, imprinting, cold extrusion, cold forging, powder pressing and other molds.

Japanese Hitachi Metal HPM50 — High Polished Pre-hard Precision Mold Steel

  • Brand: Japanese Hitachi Metal
  • Factory status: HRC38-43
  • Very Dasame DAIDO standard: NAK80
  • Wear resistance: ★★★☆☆
  • Toughness: ★★★☆☆
  • Processing: ★★★☆☆
  • Polishing: ★★★★☆
  • Corrosion resistance: ★★★☆☆
  • Product description : It has good polishing and optical rotation performance, excellent discharge performance, and the surface after treatment is very good. It can be used for etching and processing of
  • . After discharge (electric spark) processing, the surface hardness will not increase, and the subsequent processing procedures can be simplified, the tissues are uniform, and it is most suitable for precision etching, with excellent toughness and excellent mechanical characteristics. It is mainly used in mirror polishing molds.

Japanese Hitachi Metal HPM7 — Advanced Precision Plastic Mold Steel

  • Factory Status: HRC29-33
  • Quite Buderus Standard: 2738HH
  • Quite Bohler Standard: M238
  • Quite Dashi DAIDO Standard: PX88
  • Quite ASSAB Standard: 718
  • Wear Resistance: ★★★☆☆
  • Toughness: ★★★☆☆
  • Processability: ★★★★☆
  • Polishing: ★★★★☆
  • corrosion resistance: ★★★☆☆
  • product description: It is a P20+NI improvement. After special refining of new technology, the material is improved in essence, toughness, and solubleness. The hardness of large-section materials is relatively balanced. The machinability is better than that of ordinary fast-cut steel and CSM-based steel. It has excellent welding properties, good mirror processing properties, rarely produce striped structure after discharge, the hardness of the hardened surface is low, and it has good toughness and nitriding characteristics.

Japanese Hitachi Metal SLD8 — High hardness and high toughness cold work tool steel

  • Brand: Japanese Hitachi Metal
  • Factory status: HB235
  • Very similar DAIDO standard: DC53
  • wear resistance: ★★☆☆☆
  • Toughness: ★★★★☆
  • Dimensional stability: ★★☆☆
  • Processability: ★★★★☆
  • Product description: Improved version of SLD (Japanese standard SKD11). Due to the change in the amount of vanadium added, the processability has increased significantly. Toughness is more than 50% better than SLD. In terms of anti-temperature softening, the hardness of HRC62-63 can be obtained by tempering at 530°C. By using this characteristic, aging deformation and rupture and deformation during wire cutting can be suppressed. It is mainly used in precision hardware mold molding or precision parts and other molds that require both toughness and wear resistance.

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