The Bronze Age and Iron Age, which appeared after the Stone Age, are marked by the application of metal materials. Now a wide variety of metal materials have become an important material basis for the development of human society.
1.45 Steel: high-quality carbon structural steel
Main characteristics: It is the most commonly used medium carbon steel with ordinary cold plasticity. Annealing and normalizing are slightly better than quenching and tempering. It has strong strength and good machinability. After proper heat treatment, it can obtain certain toughness, plasticity and wear resistance. The comprehensive mechanical properties are good, the hardenability is low, and there is a tendency of cracking during water quenching. Small parts should be quenched and tempered to obtain higher strength and toughness; Large parts should be normalized. Therefore, 45 steel is usually used in the tempered or normalized state.
Main application: It is widely used in mechanical parts, mainly for manufacturing high strength moving parts, such as impeller, compressor piston, shaft, gear, rack, worm, etc. During welding, attention shall be paid to preheating before welding and stress relief annealing after welding.
2. Q235A (A3 steel): the most commonly used carbon structural steel
Main characteristics: good plasticity and toughness, certain elongation, good weldability, hot workability, cold stamping performance, and certain strength and cold bending performance.
Main application: widely used for parts and welding structures with general requirements. Q235A is generally used in the hot rolling state. The section steel, reinforcement, steel plate and steel pipe rolled with Q235A can also be used to manufacture various welded structural parts, bridges and generally unimportant machine parts, such as bolts, pull rods, rivets, collars and connecting rods.
3.40Cr: one of the most widely used steel grades
Medium carbon quenched and tempered steel, cold heading die steel. The steel has moderate price, easy processing, and certain toughness, plasticity and wear resistance can be obtained after proper heat treatment. Normalizing can promote the refinement of the structure, close to the equilibrium state, and improve the cutting performance of the blank. Tempered at 550~570 ℃, the steel has the best comprehensive mechanical properties. The hardenability of the steel is higher than that of 45 steel, and it is suitable for surface hardening treatment such as high-frequency quenching, flame quenching, etc.
① After quenching and tempering, this steel is used to manufacture mechanical parts that can bear medium load and medium speed, such as steering knuckle of automobile, rear half shaft, gear, shaft, worm, spline shaft, center sleeve, etc. on machine tools; ② After quenching and medium temperature tempering, it is used to manufacture parts that can withstand high load, impact and medium speed operation, such as gear, main shaft, oil pump rotor, sliding block, sleeve ring, etc; ③ After quenching and low temperature tempering, it is used to manufacture parts that bear heavy load, have low impact and wear resistance, and have a solid thickness of less than 25mm on the section, such as worm, main shaft, shaft, collar, etc; ④ After quenching and tempering and high-frequency surface quenching, it is used to manufacture parts with high surface hardness and wear resistance without great impact, such as gears, sleeves, shafts, main shafts, crankshafts, mandrels, pins, connecting rods, screws, nuts, inlet valves, etc. In addition, the steel is also suitable for manufacturing various transmission parts for carbonitriding treatment, such as gears and shafts with large diameter and good low-temperature toughness.
4. HT150: gray cast iron
Main characteristics: Most or all of the carbon in this cast iron is in the form of free flake graphite, and its fracture surface is gray, so it is called gray cast iron. It has certain mechanical properties. The mechanical properties of gray cast iron are related to the structure of the matrix and the morphology of graphite. The flake graphite in gray cast iron seriously splits the matrix, which is easy to cause stress concentration at the sharp corners of graphite, making the tensile strength, plasticity and toughness of gray cast iron much lower than that of steel, but the compressive strength is equivalent to that of steel, and it is also the cast iron with the worst mechanical properties among common cast iron castings. At the same time, the matrix structure also has a certain influence on the mechanical properties of gray cast iron. The graphite flakes of ferrite pearlite matrix gray cast iron are slightly thicker than pearlite gray cast iron, and the properties are not as good as pearlite gray cast iron. Therefore, gray cast iron with pearlitic matrix is widely used in industry. At the same time, gray cast iron has good casting performance, good vibration reduction, good wear resistance, good machining performance, and low notch sensitivity.
Main applications: castings bearing medium load, such as base, support, box, tool rest, bed, bearing seat, workbench, pulley, end cover, pump body, valve body, pipeline, flywheel, motor base, etc.
5.35 steel: high-quality carbon structural steel
Main characteristics: good plasticity and appropriate strength, good process performance, fair welding performance, mostly used in normalizing state and quenching and tempering state.
Main applications: 35 # steel is widely used to manufacture various forgings and hot pressed parts, cold drawn and upset forged steels, seamless steel pipes, and parts in mechanical manufacturing, such as crankshaft, shaft, shaft pin, lever, connecting rod, beam, sleeve, rim, washer, screws, nuts, etc.
6.65Mn: spring steel
65Mn spring steel, manganese improves hardenability, φ 12mm steel can be quenched in oil, its surface decarburization tendency is smaller than that of silicon steel, and its comprehensive mechanical properties after heat treatment are better than that of carbon steel, but it has overheating sensitivity and temper brittleness.
Small size flat and round springs, cushion springs, spring clockwork, spring rings, valve springs, clutch springs, brake springs, cold drawn steel wires, cold coiled coil springs, etc.
7.0Cr18Ni9: most commonly used stainless steel
0Cr18Ni9 stainless steel is called 06Cr19Ni10 steel in the latest standard, 304 steel in the United States and SUS304 steel in Japan.
Main characteristics: non-magnetic, good low-temperature performance. The weldment of 0Cr18Ni9 steel with thin section size has sufficient intergranular corrosion resistance, excellent corrosion resistance in oxidizing acid (HNO3), and good corrosion resistance in alkali solution, most organic acids and inorganic acids, as well as in atmosphere, water and steam.
Main applications: As a stainless heat-resistant steel, it is widely used in food equipment, general chemical equipment and other aspects, such as household products, cabinets, indoor pipelines, water heaters, boilers, bathtubs, auto parts, medical appliances, building materials, chemicals, food industry, agriculture, and ship parts.
8. Cr12: Cold working die steel
American steel grade D3, Japanese steel grade SKD1
Main characteristics: Ledeburite steel with high carbon and high chromium. The steel has high strength, good hardenability and good wear resistance; The impact toughness is poor, brittle and easy to form uneven eutectic carbide.
Main applications: Cr12 steel is a widely used cold working die steel, which is mainly used to manufacture cold punching dies, punches, blanking dies, cold heading dies, cold extrusion die punches and dies, drill sleeves, gauges, wire drawing dies, stamping dies, thread rolling plates, drawing dies, and cold pressing dies for powder metallurgy with low impact load and high wear resistance.
9. DC53: SKD11 improved new cold work die steel
Japanese steel grade S45C
Main characteristics: DC53 is a new type of cold work die steel improved by Japanese Datong special steel SKD11. Good machinability and abrasiveness. The advantage of heat treatment is that the quenching and hardening energy is higher than SKD11, so the defect of insufficient hardness during vacuum heat treatment can be improved. The advantage of wire cutting is that high temperature tempering can reduce the residual stress and eliminate the residual Vostite iron, which can prevent crazing and deformation during wire cutting. It has higher die performance in case hardening treatment. In short, it is a general cold work die steel with high hardness and toughness.
Main applications: used for precision cold stamping die, drawing die, thread rolling die, cold blanking die, punch, etc.
10. SM45: high-quality carbon plastic die steel
Main characteristics: the steel has poor hardenability. It is used to make plastic moulds of large size, which are generally hot rolled, hot forged or normalized. The hardness of the moulds is low and the wear resistance is poor. The small plastic mould can be made with higher hardness and better toughness by quenching and tempering treatment. The steel has a high carbon content, which is easy to crack after water quenching, so oil quenching is generally used. The steel has the advantages of low price, good machinability, high hardness after quenching, good strength and toughness and certain wear resistance after quenching and tempering.
Main application: It is widely used to manufacture medium and small plastic moulds of medium and low grades.
11. Cr12MoV: wear-resistant carbon molybdenum alloy steel
Main characteristics: Cr12MoV This steel has good wear resistance, hardenability, hardenability, strength and toughness, thermal stability, compressive strength, micro deformation, excellent comprehensive performance and wide adaptability.
Main applications: ordinary drawing die, punching die, blanking die, trimming die, rolling die, drawing die, cold extrusion die, cold cutting scissors, circular saw, standard tools, measuring tools, etc.
12. SKD11: ductile chromium steel
It is a Japanese tool steel grade, which is produced by Hitachi and Datong Steel Works. The SKD11 produced by Hitachi is called SLD (the latest improved version is called SLD-MAGIC), and the SKD11 produced by Datong Steel Works is called DC11.
Main characteristics: It has good toughness and high temperature fatigue resistance, can withstand temperature fusion, is suitable for long-term work under high temperature, and has good cutting and polishing properties.
Main applications: This steel is easy to turn, and suitable for making sharp knife edges, scissors, circular saws, cold or hot finishing molds, roller edges, screw lines, wire molds, milling cutters, impact molds, circular rollers, power transformer core punching molds, cutting steel sheet rolling knives, steel tube forming rollers, special forming rollers, precision gauges, cold pressing tools with complicated shapes, mandrels, metallurgy, tin working molds, plastic molds, screw head molds, etc.
13. D2: High wear resistance and micro deformation cold work die steel
Main characteristics: D2 steel not only has high wear resistance, can be vacuum heat treated to HRC60 ° - 62 °, and has excellent processing performance, but also has high hardenability and hardenability, good high-temperature oxidation resistance, good rust resistance after quenching and polishing, small heat treatment deformation, and is suitable for manufacturing various high-precision molds.
Main applications: applicable to tool steel with complex deformation, various cold stamping dies with high wear resistance and long life, cold shear blades, and thread rolling plates; Cold extrusion forming, stretch film, beer stainless steel sheet and balance cutting die for high hardness materials.
14. SKH-9: general high-speed steel with high wear resistance and toughness
Main characteristics: the carbide structure is fine, neat and well distributed. And the tissue is even. Therefore, wear resistance and toughness are relatively balanced. Especially, only the increase or decrease of carbon content will not damage the high temperature characteristics, and the steel properties can be continuously and substantially changed. High carbon steel grades are suitable for use when hardness and wear resistance are required. It has good plasticity, chippability and abrasiveness in hot and cold working.
Main applications: It is suitable for manufacturing powerful cutting wear-resistant, high-grade Heng mold, screw mold, tools that need toughness and complicated shapes, such as milling cutter, drill bit, etc.
15. ASP-23: Chromium Molybdenum Vanadium Powder High Speed Steel
Main characteristics: high wear resistance (abrasion resistance), high compressive strength, very good hardenability, good toughness, good dimensional stability of heat treatment, and good tempering softening resistance.
Main application: especially suitable for blanking and forming of thin processed materials. For example: blanking of medium carbon steel or high carbon steel, punching of hardened steel plate or cold rolled steel strip, plastic mould containing glass fiber.