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Commonly used metal materials and their characteristics, advantages and disadvantages in CNC machining and mold processing

October 6, 2023

1. 45—high quality carbon structural steel, the most commonly used medium carbon quenched and tempered steel


Main features: the most commonly used medium carbon quenched and tempered steel has good comprehensive mechanical properties, low hardenability, and is prone to cracks during water quenching. Small parts should be quenched and tempered, and large parts should be normalized. Application examples: mainly used to manufacture high-strength moving parts, such as turbine impellers and compressor pistons. Shafts, gears, racks, worms, etc. Pay attention to preheating of welded parts before welding and stress relief annealing after welding.


2. Q235A (A3 steel)—the most commonly used carbon structural steel


Main features: high plasticity, toughness, welding performance, cold stamping performance, certain strength, and good cold bending performance. Application examples: widely used in parts and welded structures with general requirements. Such as tie rods, connecting rods, pins, shafts, screws, nuts, ferrules, brackets, machine bases, building structures, bridges, etc, that are not subject to large forces.


3. 40Cr—one of the most widely used steel types, belonging to alloy structural steel


Main features: after quenching and tempering treatment, it has good comprehensive mechanical properties, low temperature impact toughness and low notch sensitivity. It has good hardenability. It can obtain high fatigue strength when oil-cooled. Parts with complex shapes can be easily processed when water-cooled. Cracks occur, the cold bending plasticity is medium, and the machinability is good after tempering or quenching and tempering, but the weldability is not good and cracks are prone to occur. It should be preheated to 100~150℃ before welding. It is generally used in the quenched and tempered state. It can also Carbonitriding and high-frequency surface quenching are performed. Application examples: After quenching and tempering, it is used to manufacture medium-speed and medium-load parts, such as machine tool gears, shafts, worms, spline shafts, ejector pin sleeves, etc. After quenching and tempering and high-frequency surface quenching, it is used to manufacture high-hardness, durable parts. Grinding parts, such as gears, shafts, spindles, crankshafts, spindles, sleeves, pins, connecting rods, screws and nuts, intake valves, etc., are used to make heavy-duty, medium-speed impact parts after quenching and medium-temperature tempering. Parts, such as oil pump rotors, sliders, gears, spindles, collars, etc., are quenched and tempered at low temperatures to make heavy-duty, low-impact, wear-resistant parts, such as worms, spindles, shafts, collars, etc, carbon the nitriding process is used to manufacture transmission parts with larger sizes and higher low-temperature impact toughness, such as shafts, gears, etc.


4. HT150—gray cast iron


Application examples: gear box, machine tool bed, box, hydraulic cylinder, pump body, valve body, flywheel, cylinder head, pulley, bearing cover, etc.


5. 35—commonly used materials for various standard parts and fasteners


Main features: appropriate strength, good plasticity, high cold plasticity, and acceptable weldability. It can be partially upsetting and drawing in the cold state. Low hardenability, use after normalizing or quenching and tempering, application examples: suitable for manufacturing small-section parts, parts that can withstand larger loads: such as crankshafts, levers, connecting rods, shackles, etc, various standard parts, fasteners.


6. 65Mn—commonly used spring steel


Application examples: various small-sized flat and round springs, seat springs, spring springs, spring rings, valve springs, clutch reeds, brake springs, cold-rolled coil springs, circlips, etc.


7. 0Cr18Ni9—the most commonly used stainless steel (US steel number 304, Japanese steel number SUS304)


Characteristics and applications: it's the most widely used as stainless heat-resistant steel, such as food equipment, general chemical equipment, and energy industrial equipment.


8. Cr12—commonly used cold work die steel (US steel number D3, Japanese steel number SKD1)


Characteristics and applications: Cr12 steel is a widely used cold work die steel, which is a high-carbon, high-chromium ledeburite steel. This steel has good hardenability and good wear resistance, because the carbon content of Cr12 steel is as high as 2.3%, it has poor impact toughness, is prone to brittleness, and is prone to forming uneven eutectic carbides, Cr12 Due to its good wear resistance, steel is mostly used to manufacture cold punching dies, punches, blanking dies, cold heading dies, cold extrusion dies, punches and dies, and drill bushings that are subject to small impact loads and require high wear resistance, gauges, wire drawing dies, impression dies, wire rolling boards, drawing dies and cold pressing dies for powder metallurgy, etc.


9. DC53—commonly used cold work die steel imported from Japan


Characteristics and applications: high-strength and toughness cold work die steel, steel grade manufactured by Japan's Datong Special Steel Co., Ltd. After high temperature tempering, it has high hardness, high toughness and good wire cutting properties. Used for precision cold stamping dies, drawing dies, wire rolling dies, cold blanking dies, punches, etc. 10. SM45 - ordinary carbon plastic mold steel (Japanese steel number S45C).


10. DCCr12MOV—wear resistant chromium steel


Domestic, it has lower carbon content than Cr12 steel, and with the addition of Mo and V, carbide unevenness has been improved. MO can reduce carbide segregation and improve hardenability, and V can refine grains and increase toughness. This steel has high hardenability, and the cross section can be completely hardened below 400mm. It can still maintain good hardness and wear resistance at 300~400℃. It has higher toughness than Cr12, has small volume change during quenching, and has high Wear resistance and good overall mechanical properties. Therefore, various molds with large cross-sections, complex shapes, and large impacts can be manufactured, such as ordinary drawing dies, punching dies, punching dies, blanking dies, trimming dies, rolling dies, wire drawing dies, and cold extrusion dies. Cold cutting scissors, circular saws, standard tools, measuring tools, etc.


11. SKD11—tough chromium steel


Produced by Hitachi Co., Ltd., Japan. Technically improve the casting structure in steel and refine the grains. Compared with Cr12mov, its toughness and wear resistance are improved. Extends the service life of the mold.


12. D2—high carbon, high chromium cold work steel


Made in the United States. It has high hardenability, hardenability, wear resistance, good high-temperature oxidation resistance, good rust resistance after quenching and polishing, and small heat treatment deformation. It is suitable for manufacturing various cold work molds, cutting tools and tools that require high precision and long life. Measuring tools, such as stretching dies, cold extrusion dies, cold shearing knives, etc.


13. SKD11 (SLD)—non deformation tough high chromium steel


Produced by Hitachi Co., Ltd., Japan. As the MO and V content in the steel increases, the casting structure of the steel is improved, the grains are refined, and the carbide morphology is improved. Therefore, the strength and toughness (bending strength, deflection, impact toughness, etc.) of this steel are higher than those of SKD1. With high D2, the wear resistance is also increased, and it has higher temper resistance. Practice has proven that the life of this steel mold is improved compared to Cr12mov. Often used to manufacture molds with high requirements, such as drawing molds, impact grinding wheel molds, etc.


14. DC53—high toughness high chromium steel


Produced by Daido Co., Ltd. of Japan. The heat treatment hardness is higher than SKD11. After tempering at high temperature (520-530), it can reach a high hardness of 62-63HRC. DC53 exceeds SKD11 in terms of strength and wear resistance. The toughness is twice that of SKD11. The toughness of DC53 rarely causes cracks and cracks in cold work mold manufacturing. The service life is greatly improved. The residual stress is small. After high temperature, the residual stress is reduced. Because cracks and deformation after wire cutting are suppressed. Cutting and grinding properties exceed SKD11. Used for precision stamping dies, cold forging, deep drawing dies, etc.


15. SKH-9—General-purpose high-speed steel with high wear resistance and toughness


Produced by Hitachi Co., Ltd., Japan. Used for cold forging dies, strip cutting machines, drill bits, reamers, punches, etc.


16. ASP-23—powder metallurgy high speed steel


Made in Sweden. The carbide distribution is extremely uniform, wear-resistant, high toughness, easy to process, and dimensionally stable after heat treatment. Used for various long-life cutting tools such as punches, deep drawing dies, drilling dies, milling cutters and shear blades.


17. P20—Generally required large and small plastic molds


Made in the United States. Can be operated by electro-erosion. Factory pre-hardened HB270-300. Quenching hardness HRC52.


18. 718—Highly demanding large and small plastic molds


Made in Sweden. Especially electrolytic corrosion operations. Factory pre-hardened HB290-330. Quenching hardness HRC52.


19. Nak80—high mirror surface, high precision plastic mold


Produced by Daido Co., Ltd. of Japan. Factory pre-hardened HB370-400. Quenching hardness HRC52.


20. S136—corrosion-resistant and mirror-polished plastic mold


Made in Sweden. Factory pre-hardened HB<215. Quenching hardness HRC52.


21. H13—commonly used die casting molds


For aluminum, zinc, magnesium and alloy die casting. Hot stamping die, aluminum extrusion die.


22. SKD61—advanced die casting mold


Produced by Japan's Hitachi Co., Ltd., with electric ballast re-dissolution technology, its service life is significantly improved compared to H13. Hot stamping die, aluminum extrusion die.


23. 8407—Advanced die casting mold


Made in Sweden. Hot stamping die, aluminum extrusion die.


24. FDAC


Sulfur is added to enhance its machinability. The factory pre-hardened hardness is 338-42HRC, and can be directly carved without quenching or tempering. Used for small batch molds, simple molds, various resin products, sliding parts, and mold parts with short delivery times. Zipper mold, glasses frame mold.