Tungsten carbide reinforced composite material strengthened layer of mould steel basal body and preparation process thereof

Abstract

The invention relates to a tungsten carbide reinforced composite material strengthened layer of a mould steel basal body and a preparation process thereof, belonging to the technical fields of surface material preparation and surface processing. A surface strengthened layer comprises the following chemical components in percentage by weight: 1.85-2.45% of C, 2.90-3.85% of Si, 12.45-15.25% of Cr, 3.10-3.65% of B, 7.55-8.50% of W, 2.20-2.85% of Co, 4.50-5.50% of Fe, and the balance of Ni. Main strengthened phases in a spray welding layer comprise WC, Cr7C3, Ni4B3 and Co7W6. The process for preparing the surface strengthened layer through plasma spray welding comprises the following steps of: cleaning the surface of an H13 steel basal body; preparing the spray welding layer with required thickness by using mixed gas of argon and hydrogen; and controlling the overlapping amount between every two spray welding layer, wherein the obtained composite material surface layer can achieve the functions of repairing defects or strengthening the basal body; and the service life of a mould is recovered and prolonged.

Description

Technical field: [0001] The invention relates to a tungsten carbide-reinforced composite material surface reinforcement layer for a mold steel matrix, and belongs to the technical field of surface material preparation and surface processing. Background technique: [0002] At present, the surface defects of the mold are repaired or strengthened by arc surfacing, electric spark deposition, brush plating, laser cladding or "spraying + remelting" to prepare the mold surface repair layer or strengthening layer. H13 steel (US brand) is a strong and tough hot work die steel widely used in the world, which is equivalent to 4Cr5MoSiV1 in China, SKD61 in Japan and 1.2344 in Germany. Due to the high content of carbon and vanadium, the steel has high hardenability, thermal cracking resistance, good heat resistance and heat strength, and high stability against tempering. Based on the good comprehensive properties of the steel, it has been widely used in hammer forging dies, hot extrusio...

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Problems solved by technology

In the process of preparing the surface repair (strengthening) layer of the mold, the arc surfacing welding often causes a large heat-affected zone on the repaired mold due to the large amount of heat input, which easily leads to deformation or even cracking of the mold; the electric spark deposition method, Due to the uncertain quality of the bonding between the deposited layer and the matrix, especially the discontinuous porosity and compactness, some proposed repair materials, such as alloy systems, have complex components, or for high hardness and high strength materials, it is difficult to process them into wires required by electrodes. material or bar, and when the amount of repair is large, the production efficiency is extremely low and the repair cost is high (Xu Dong et al.: Application of EDM surface treatment technology on molds. Equipment Manufacturing Technology, 2010, 4: 150-153) ; For the brush plating method, the coating is generally very thin, mostly less than 0.3mm, and because the combination of the coating and the substrate is a mechanical combination, the bonding strength with the substrate is low, which greatly limits the practical application of the above methods (Zhao Weilin et al.: Brush Plating and Spray Welding Rapid Repair of Automotive Molds. Mold Industry, 2007, 33(2), 64-66); Due to the large investment in equipment at one time, the laser cladding method still has certain difficulties in promotion and application (Jiang Shengbo et al: Microstructure and Properties of Laser Cladding Repairing Scrapped Forging Die Coatings. Material Heat Treatment Technology, 2009(38), 86-88)

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