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Since it is more difficult than general cutting, the cutting fluid of such materials must also have different properties, and it is hoped that it will be beneficial to reduce the cutting difficulty. Among the difficult-to-cut materials, some have higher hardness, reaching 65-70HRC; some have very low thermal conductivity, so that the heat in the cutting zone cannot be conducted quickly; others are very high in hardness and strength, and the material is chemically active, elastic mode. The extremely small amount and large elastic recovery and large elongation rate all cause cutting difficulties.

When cutting various difficult-to-cut materials, select the appropriate cutting fluid according to the respective properties, cutting characteristics and processing stages of the material to be cut. The purpose is to improve the machinability of difficult-to-cut materials to achieve the purpose of processing. Commonly used cutting fluids include aqueous solution, common emulsion, extreme pressure emulsion, mineral oil, vegetable oil, animal oil, extreme pressure cutting oil, etc. Various cutting fluids will have different effects on the above materials.
For high-strength steel, in addition to the common cutting fluid and extreme pressure cutting fluid, it can also use soybean oil or rapeseed oil as the tapping cutting fluid, which can also have good results.