coercive force

it indirectly reflects the grain size of hard phase in the alloy. Coercive force (iso3326) is the residual magnetism in a hysteresis loop after magnetization and demagnetization of the bonding phase in cemented carbide. Because there is a direct relationship between the average grain size of tungsten carbide phase and coercivity, it is an important nondestructive test method in industry. The finer the tungsten carbide phase, the higher the coercive force value.

cobalt magnetism

Indirectly reflects the control of alloy carbon content. Magnetic saturation — cobalt is magnetic, while tungsten carbide crystals and cubic tungsten carbide crystals (TIC, TAC, NBC, VC, etc.) are non-magnetic. Therefore, if the magnetic saturation value of cobalt in a brand is measured, and then compared with the corresponding value of the sample containing pure cobalt, the alloying level of cobalt bonding phase can be obtained. This test is used to determine any deviation from the optimal carbon content. Low magnetic saturation value indicates the existence of carbon content / or carbide phase, and high magnetic saturation value indicates the existence of free carbon or graphite phase


chemical composition and internal residual pores of the alloy. Density (iso3369) is the ratio of mass to volume of materials, which is usually measured by drainage method. Density is usually used to determine the accuracy of a brand composition in the cemented carbide industry. Different from the general understanding, the porosity level of modern cemented carbide cannot be determined by measuring density. The density of tungsten carbide (WC) is 15.7g/cm3, and the density of cobalt (CO) is 8.9g/cm3. Therefore, for WC Co brand, the density decreases with the increase of cobalt content.


it reflects the grain size of the alloy and the wear resistance of the material. Hardness (ISO 3738 and ISO 3878) the ability of a material to resist local plastic deformation. The commonly used hardness measurement methods of cemented carbide are Rockwell hardness or Vickers hardness measurement, and the units are HRA and HV respectively. Vickers hardness measurement method uses a standard pyramid diamond with a square base to penetrate the sample surface under certain load conditions. The hardness value can be obtained by measuring the diagonal of the indentation. The common preload pressure of cemented carbide is 3kg (HV30). It should be noted that because the two measurement methods are different, the conversion of the two hardness values should be converted according to the reference table of the measured materials.

bending strength

it reflects the relationship between the comprehensive performance, organizational structure and quality of the material as a whole. Bending strength (ISO 3327) refers to the ability of a material to resist continuous cracking in bending. Its value is the stress measured at the breaking point of the material in a standard three-point bending test. TRS uses the average of several measured values as the measured value. This value can vary greatly with the sample geometry, surface state and experimental equipment. In particular, this result is sensitive to surface finish, surface residual stress, surface corrosion and internal defects of the material. It must be noted that TRS value cannot only be used as the standard for brand selection.

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