Cemented carbide is made by powder metallurgy with one or more refractory carbides (tungsten carbide, titanium carbide, etc.) powder as the main component, adding metal powder (cobalt, nickel, etc.) as a bonding agent Alloy. It is mainly used to manufacture high-speed cutting tools and cutting tools for hard and tough materials, as well as cold-work molds, measuring tools, and high wear-resistant parts that are not subject to impact and vibration.
The characteristics of cemented carbide
⑴High hardness, wear resistance and red hardness
The hardness of cemented carbide can reach 86～93HRA at room temperature, which is equivalent to 69～81HRC. It can maintain high hardness at 900～1000℃ and has excellent wear resistance. Compared with high-speed tool steel, the cutting speed can be 4 to 7 times higher, the service life is 5 to 80 times longer, and hard materials with a hardness of up to 50HRC can be cut.
⑵High strength and elastic modulus
The compressive strength of cemented carbide is as high as 6000MPa, and the modulus of elasticity is (4～7)×105MPa, which is higher than that of high-speed steel. But its flexural strength is low, generally 1,000 to 3,000 MPa.
⑶ Good corrosion resistance and oxidation resistance
Generally, it has good resistance to atmospheric, acid, alkali and other corrosion, and it is not easy to oxidize.
⑷Small linear expansion coefficient
When working, the shape and size are stable.
⑸The shaped products are no longer processed and reground
Due to the high hardness and brittleness of cemented carbide, it is no longer necessary to cut or regrind after powder metallurgy forming and sintering. When special reprocessing is required, only electrical processing such as electric spark, wire cutting, electrolytic grinding or special grinding wheel grinding can be used. cut. Products of a certain specification usually made of cemented carbide are brazed, bonded or mechanically clamped on the cutter body or mold body for use.
Application of cemented carbide
⑴ Tool material
Cemented carbide has the largest number of tool materials, which can be used to make turning tools, milling cutters, planers, drills, etc. Among them, tungsten-cobalt cemented carbide is suitable for the processing of short chips of ferrous metals and non-ferrous metals and the processing of non-metallic materials, such as cast iron, cast brass, bakelite, etc.; tungsten-titanium-cobalt cemented carbide is suitable for the long-term processing of ferrous metals such as steel. Chip processing. Among similar alloys, the one with more cobalt content is suitable for rough machining, and the one with less cobalt content is suitable for finishing. The machining life of general-purpose cemented carbide for difficult-to-machine materials such as stainless steel is much longer than that of other cemented carbides.
Cemented carbide is mainly used as cold drawing dies, cold punching dies, cold extrusion dies, cold forging dies and other cold working dies.
⑶ Measuring tools and wear-resistant parts
Cemented carbide is used for wear-resistant parts such as wear-resistant surface inlays and parts of measuring tools, precision bearings of grinders, guide plates and guide rods of centerless grinders, and center of lathes.
Post time: Nov-18-2021