A coating alloy for repairing tungsten-based powder alloy die-casting mold and its preparation method

Abstract

The invention discloses a coating alloy for repairing a tungsten-based powder alloy die-casting mold and a preparation method thereof. The coating alloy for repairing the tungsten-based powder alloy die-casting mold aims to repair a local abrasion surface of the mold, so that the size and the function of the mold are restored and reused, and the performance of the surface of the mold is improved.According to the core technology, the multi-layer composite coating alloy with different functionalities is formed through superposition of multiple surface technologies, the coating alloy is cobalt,chromium, tungsten, iron and tungsten carbide alloy, the coating alloy is prepared from the following components of, by mass in percentage (Wt / %), 45%-50% of the cobalt (Co), 30%-40% of the chromium (Cr), 2%-4% of the tungsten (W), 2%-4% of the tungsten carbide (WC), and the balance iron (Fe).

Description

technical field [0001] The invention relates to a coating alloy for repairing a tungsten-based powder alloy die-casting mold and a preparation method thereof. A high-energy-density laser beam is used to heat and melt the coating alloy and rapidly solidify to form a metallurgical bond with the matrix. The invention provides a wear-resistant coating and belongs to the field of material science and engineering. Background technique [0002] Tungsten-based powder alloy is a composite material composed of tungsten as the hard phase and nickel, copper or nickel, iron, etc. as the binder phase. It has high thermal conductivity, high strength, high density, low thermal expansion coefficient and excellent corrosion resistance. It is one of the best materials for manufacturing high-precision molds and die-casting molds. During the die-casting production process of tungsten-based powder alloy die-casting molds, molten non-ferrous metal liquid enters the mold cavity at high pressure, h...

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Problems solved by technology

Due to its special physical and chemical properties, tungsten-based powder alloys have strong thermal conductivity and small linear expansion coefficient; tungsten has a high melting point and does not form alloys with most metals. Even if alloys are formed, they are mostly intermetallic compounds. Engineering technology is used to repair the worn part of the working surface of the tungsten-based powder alloy die-casting mold cavity. The main problem is that there is a large difference in the chemical composition and performance of the repair layer and the base material, and the compatibility and combination of the materials are poor. During the production process of the repaired tungsten-based powder alloy die-casting mold, the repair layer on the surface of the cavity is washed by the high pressure, high temperature and high speed of the molten metal. At the same time, there is heat released during the solidification process of the molten metal, and the surface of the cavity The repair layer first reaches a higher temperature and expands; after the mold is opened, the repair layer on the surface of the cavity contacts with air and shrinks to produce tensile stress. Cracks, which eventually lead to cracking and peeling of the repair layer as the number of productions increases

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