Preparation method of polycrystalline diamond wire-drawing die and synthetic block of polycrystalline diamond wire-drawing die

Abstract

The invention belongs to the field of wire-drawing die preparation, and particularly relates to a preparation method of a polycrystalline diamond wire-drawing die. The preparation method of the polycrystalline diamond wire-drawing die comprises the following steps that S1, a wire-drawing die blank is prepared, an inner hole is preset in the middle of the wire-drawing die blank, and an annular inner assembly block with the inner hole is formed in a pre-pressing mode for later use; S2, a synthetic block is assembled: putting the inner assembly block into a pyrophyllite assembly block to prepare the synthetic block; and S3, the synthetic block is sintered; and the synthesized block is sintered in a cubic press. According to the preparation method, an inner heating pipe and an outer heating pipe are respectively arranged at the center and the outer part of the inner assembly block to heat the inner part and the outer part of the inner assembly block at the same time, so that the radial temperature gradient difference of the inner assembly block is reduced, the heating uniformity of the inner assembly block is improved, and the quality defects of cracks, uneven sintering and the like after the wire-drawing die blank is synthesized are greatly reduced.

Description

technical field [0001] The invention belongs to the technical field of preparation of polycrystalline diamond wire drawing die blanks, and in particular relates to a method for preparing polycrystalline diamond wire drawing dies and a synthetic block thereof. Background technique [0002] With the development of the economy, various large-size metal pipes, wires and bars with high strength and high precision are more and more widely used in communication, transportation, energy, aerospace and other fields, for high-precision pipeline bars The production of polycrystalline diamond usually adopts wire drawing process. Because polycrystalline diamond has the advantages of high hardness, good shape retention and high cost performance, it has more and more replaced traditional carbide wire drawing dies. At present, domestic large-size polycrystalline The six-sided top press is sintered at high temperature and high pressure. During the sintering process, the graphite tube is energ...

AI Technical Summary

Problems solved by technology

[0002] With the development of the economy, various large-size metal tubes, wires, and rods with high strength and high precision are more and more widely used in communication, transportation, energy, aerospace and other fields, for high-precision pipeline rods The production of polycrystalline diamond usually adopts wire drawing process. Because polycrystalline diamond has the advantages of high hardness, good shape retention and high cost performance, it has more and more replaced traditional carbide wire drawing dies. At present, domestic large-size polycrystalline The six-sided top press is sintered at high temperature and high pressure. During the sintering process, the graphite tube is energized to heat the assembly block, and the inner assembly block is placed inside the graphite tube. However, due to the large size of the large-size polycrystalline diamond wire drawing die blank, the drawing die blank is from outside to inside. The temperature gradient is large, and most of the synthesized products have quality problems such as cracking caused by uneven sintering; secondly, due to the traditional anvil structure that limits the structure of the synthesis block, the six faces of the assembly block are subject to the same pressure during the synthesis process. The lateral circumferential pressure gradient is not the same, the synthetic product is easily deformed, the dimensional accuracy of the product is poor, the thickness of the diamond layer and the internal stress distribution are uneven, which affects the quality of the product and subsequent processing, and the larger the size of the synthetic product, this The impact is also greater; at the same time, in actual production, the direct mixing of diamond powder and cobalt powder has the problem of uneven mixing, especially fine-grained diamond powder and cobalt powder with smaller particle sizes, which are very prone to agglomeration, which is difficult for ordinary mixing methods. Realize uniform mixing, resulting in the problem of cobalt agglomeration in the sintered body, which also greatly affects the quality of the product

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