WC-Co and CBN-Co gradient compound tool material and preparation method

Abstract

The invention discloses a WC-Co and CBN-Co gradient compound tool material. The WC-Co and CBN-Co gradient compound tool material is composed of a matrix layer, a connecting layer, a first transition layer, a second transition layer and an outer wear-resisting layer. The matrix layer is made of WC-Co. The connecting layer, the first transition layer, the second transition layer and the outer wear-resisting layer are all made of mixed powder of WC-Co and CBN-Co, and the mass fraction of the WC-Co is decreased in a gradient mode from the connecting layer to the outer wear-resisting layer. The surface of WC powder and the surface of CBN powder are coated with metal Co by means of chemical plating, WC-Co powder and CBN-Co powder are obtained, and the WC-Co is used as the matrix layer. The mixed powder of the WC-Co and the CBN-Co is used as the connecting layer, the first transition layer, the second transition layer and the outer wear-resisting layer in different mixing ratios, the prepared powder is evenly pressurized under the vacuum condition for performing spark plasma sintering after being sequentially filled into a graphite mold, natural cooling is conducted to an indoor temperature after power failure, and accordingly the gradient compound tool material is obtained. The gradient compound tool material has the superior hardness, superior abrasive resistance and low friction coefficient, and 'the irreconcilable contradiction of hardness and toughness' of a ceramic composite material is solved to a certain extent.

Description

technical field [0001] The invention belongs to the technical field of tool materials and processing, and in particular relates to a WC-Co and CBN-Co gradient composite tool material and a preparation method. Background technique [0002] In the machining process, the cutting tool is the main direct performer of the cutting process, and there are inevitably wear, damage or even fracture phenomena during the cutting process of the workpiece, especially in high-speed cutting, the wear of the tool is particularly serious; After the phenomenon, the service life of the tool will drop sharply, and the surface roughness of the processed workpiece will increase, which will easily cause the size of the workpiece to exceed the design tolerance. Molds and other equipment with high processing difficulty, especially large-scale parts or precision parts with national defense requirements, excessive tool changes will increase the repeated positioning error of the parts, which cannot meet t...

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Problems solved by technology

[0004] Although the CVD coating has good wear resistance, the CVD process also has its inherent defects: first, the process temperature is high, which may easily cause the bending strength of the tool material to decrease; Micro-cracks are generated when the CVD process is used; the third is that the waste gas and waste liquid discharged by the CVD process will cause relatively large environmental pollution

[0006] A Chinese patent discloses a gradient laminated coating tool and its preparation method (ZL 201110214393.2). The prepared ZrTiN composite coating tool has high hardness and strength, excellent wear resistance and corrosion resistance, but it is not suitable for cutting non-ferrous metal materials. When the surface friction coefficient is high, the service life of the tool cannot meet the needs of use

Since both WC and CBN are very difficult to sinter, and there is direct contact between WC particles and CBN particles during the sintering process, it is very difficult to prepare high-performance WC-Co-CBN composites under this condition.

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