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Research Of Flux-cored Wire For Hardfacing With Abrasion Resistance And Hardfacing Alloys Reinforced With TiB2

Posted on:2013-07-03Degree:MasterType:Thesis
Country:ChinaCandidate:F B WeiFull Text:PDF
GTID:2231330371990183Subject:Materials Processing Engineering
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High hardness wear-resistant hardfacing flux-cored wires are widely adapted to the production of wear parts and repair work of hardfacing in energy, mining field, etc. However, there is still a big gap between domestic high hardness wear-resistant hardfacing flux-cored wires and foreign famous brand wires considering their comprehensive performance, especially wear resistance. There are lots of work to complete on the study of strengthening and wear-resisting mechanism of the wear-resistant hardfacing alloys.The main factors that influence wear-resistant hardfacing alloy performance consist of the alloy’s component, microstructural of the hardfacing alloys, welding technology parameters and welding heat treatment, etc. This paper, in light of the current theoretical basis and practical requirement of wear-resistant hardfacing flux-cored wire, put forward the new design proposal of adding alloy elements to the traditional metal powder flux-cored wire. In this paper, through adding TiB2ceramic powder with different content to the Fe-Cr-C flux-cored wire, two self-shielded flux-cored wires for hardfacing with high hardness and abrasion resistance reinforced with TiB2were produced. Fe-Cr-C surfacing alloys reinforced with TiB2were produced by arc surfacing. The processing property、microstructure of hardfacing alloys and effects of TiB2in flux-cored wire on properties(Hardness and Wear resistance) were investigated by means of a optical microscope(OM), scanning electron microanalysis(SEM), X-ray diffractometer(XRD). The process performance and microstructure were studied by a series of experimental tests, the effects of TiB2content on the hardfacing alloy’s performance (Hardness and Abrasion resistance) were analyzed. The results go as following:(1) Fe-Cr-C hardfacing alloys reinforced with TiB2were produced by arc hardfacing, whose welding manufacturability meets the application requirements. Combining with experiments, the grinding rolls produced by the best process specifications have been used in production.(2) The newly developed hardfacing alloy’s microstructure reinforced with TiB2are composed of primary carbides, martensite and a small amount of residual austenite, which is a kind of optimization typical wear-resistant hardfacing alloy’s organization category. Meanwhile, TiC-TiB2composite compound particle was formed and dispersed in the primary carbides and matrix structures by adding TiB2.(3) TiB2reinforced Fe-Cr-C surfacing alloys have higher hardness and better wear resistance. Especially, when added10wt%TiB2, the average hardness value of the hardfacing alloy achieved68.4HRC, and wear resistance is1.2times of that of the normal Fe-Cr-C hardfacing alloy. By microhardness testing, hardness of primary carbides and matrix texture of TiB2reinforced Fe-Cr-C hardfacing alloys are the highest.(4) One of the reasons which leads to the increase of hardfacing alloy’s hardness and wear resistance is that the adding of TiB2ceramic powders has increased the particles of crystal nucleation in hardfacing alloys, which improved the nucleation rate of primary carbides, interrupted the growth of columnar crystal and inhibited its grain growth, making its size smaller and increasing the number of wear-resistant hard phase.
Keywords/Search Tags:titanium boride, flux-cored wire, hardfacing, wear properties
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