多元复合强化耐磨堆焊药芯焊丝的研究

发布时间：2018-02-05 05:48

本文关键词： 药芯焊丝堆焊合金硬质相耐磨性能　出处：《沈阳工业大学》2017年硕士论文　论文类型：学位论文

【摘要】：工业的快速发展对耐磨材料提出了更高的要求。在零部件的表面熔敷一层耐磨性较高的金属层,可以有效提高其使用寿命。本文以传统的Fe-Cr-C合金体系为基础,以Fe-Cr-C-B、Fe-Cr-C-B-Nb、Fe-Cr-C-B-Ti三种合金体系为研究对象,制备了多元复合强化耐磨堆焊药芯焊丝。采用自保护明弧堆焊法制备堆焊层,探讨了堆焊层中硬质相的种类和分布形态,分析了元素含量变化对堆焊层硬度和耐磨性的影响。在Fe-Cr-C-B系堆焊合金中,优化了Cr元素的含量。并在此基础上,研究硼元素加入对堆焊层显微组织和耐磨性的影响。随着硼元素的增加,显微组织由M23C6向M_(23)(C,B)_6转变,弥散分布的硼化物,呈层片状、菊花状等。耐磨性实验结果表明,适量的硼元素可改善Fe-Cr-C-B系堆焊合金的耐磨性,其耐磨性与硼化物数量,致密度和尺寸有关。在Fe-Cr-C-B-Nb系堆焊合金中,制备的堆焊合金显微组织为马氏体,残余奥氏体,M_(23)(C,B)_6和NbC。硼化物M_(23)(C,B)_6沿晶界分布,NbC呈规则四边形弥散分布在基体中。NbC先于M_(23)(C,B)_6生成。过量的B元素不利于NbC析出,使Nb元素固溶强化硼化物和基体。耐磨性实验结果表明,M_(23)(C,B)_6和NbC两种硬质相显著改善了Fe-Cr-C-B-Nb系堆焊合金的耐磨性。在Fe-Cr-C-B-Ti系堆焊合金中,堆焊层中原位合成了TiC和M_(23)(C,B)_6两种硬质相。随着钛含量的增加,显微组织中TiC的数量逐渐增加,并沿晶界分布。硼含量的提高,使TiC的数量不稳定。TiC作为形核衬底,为M_(23)(C,B)_6附生生长提供条件。原位合成TiC和M_(23)(C,B)_6两种硬质相,可提高堆焊层的综合性能。
[Abstract]:The rapid development of industry has put forward higher requirements for wear-resistant materials. A metal layer with high wear resistance is deposited on the surface of parts and components. This paper is based on the traditional Fe-Cr-C alloy system and Fe-Cr-C-Bnb Fe-Cr-C-B-Nb. Three kinds of Fe-Cr-C-B-Ti alloy systems were used to prepare multicomponent composite and wear-resistant surfacing flux-cored wire and self-protective bright arc surfacing method was used to prepare surfacing layer. The types and distribution of hard phases in surfacing layer were discussed, and the effect of element content on hardness and wear resistance of surfacing layer was analyzed. In Fe-Cr-C-B surfacing alloy. The content of Cr was optimized. On this basis, the effect of boron addition on the microstructure and wear resistance of surfacing layer was studied. With the increase of boron element, the microstructure changed from M23C6 to M2C23C. The results of wear resistance test showed that the appropriate amount of boron could improve the wear resistance of Fe-Cr-C-B surfacing alloy. The wear resistance is related to the quantity, density and size of boride. In the Fe-Cr-C-B-Nb surfacing alloy, the microstructure of the surfacing alloy is martensite and residual austenite. M / C / C / C / C / B / C / C / C / C / C / C / C / C / C / C / C / C / C / C / C / C / C / C / C / C / C / C / C / C / C / C /. NbC is distributed in matrix as regular quadrilateral dispersion. NbC is formed earlier than M _ S _ 2O _ 3 / C _ B _ 6. Excessive B element is not conducive to the precipitation of NbC. The solid solution of NB element was used to strengthen the boride and matrix. The wear resistance of Fe-Cr-C-B-Nb surfacing alloys was improved remarkably by two hard phases, BX _ 6 and NbC. In Fe-Cr-C-B-Ti surfacing alloys, the wear resistance of the surfacing alloys was improved. In the surfacing layer, two kinds of hard phases, TiC and M _ (+ +) _ (23) C ~ (+ +) C ~ (2 +), were synthesized in situ. With the increase of titanium content, the amount of TiC in microstructure increased gradually. With the increase of boron content along grain boundaries, the quantity of TiC is unstable. Tic is used as nucleation substrate. In situ synthesis of two hard phases, TiC and MK23, can improve the comprehensive properties of the surfacing layer.
【学位授予单位】：沈阳工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TG455

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