摘 要：高铬铸铁堆焊合金优良的耐磨性已成为广泛的共识，但是当其运用于氧化铝精炼厂的拜耳精炼过程中的浆料泵组件和管道时，不仅需要有良好的耐磨性，而且还需要较好的耐腐蚀性。

本文开发了一种新型无渣型铁基自保护药芯焊丝（SSFCW），其具有不同的钛含量，以制造堆焊合金。钛可以使用铝镁合金粉末和焊丝中的石墨转移到熔池，作为更强的脱氧剂。通过X射线衍射和扫描电子显微镜来观察得到所制备的合金的相组成和微观结构。结果表明，TiC优先在合金中形成，它主要作为一次M7(C,B)3（M 主要是Cr和Fe）碳化物的形核核心，并且把钛添加到药芯焊丝中时，降低了M7(C,B)3的数量。当添加Ti元素时，由于形成TiC，消耗了碳，所以合金的显微组织从过共晶组织变为亚共晶组织。向铁基SSFCW添加钛可提高合金的耐磨性和耐腐蚀性，以及得到相对较高的硬度和细化的微观结构。

在本研究中，将高铬铸铁耐磨合金放置于PH约为14的碱性溶液中，使用电化学腐蚀技术研究腐蚀行为，针对Ti对高铬合金堆焊层耐腐蚀性的影响进行了研究。实验结果表明: 钛能够改善合金的耐腐蚀性，这与添加钛元素引起的微观结构变化有关，钛含量的增加减少了晶界的碳化物的量，提高了溶解在铁基体中的铬的量，从而使得高铬铸铁堆焊合金具有优异的耐腐蚀性。

较高的钛含量会减小晶粒的尺寸以及降低碳化物含量，碱性介质中的耐腐蚀性随着基体中铬含量提高而升高。

关键词：自保护明弧堆焊；高铬铸铁；合金元素 Ti；微观组织；耐腐蚀性

Abstract：The abrasion resistance of high chromium cast iron wear resistant alloys using surfacing methods has been widely recognized. These materials not only need to have good wear resistance, but also need better corrosion resistance.

In this study, a new slag-free Fe-based self-shielded flux cored wire (SSFCW) was developed with different titanium content to produce experimental surfacing alloys. Titanium can be transferred to the molten pool using aluminum-magnesium alloy powder and graphite in the wire as a stronger deoxidizer. The phase composition and microstructure of the prepared alloy were observed by X-ray diffraction and scanning electron microscopy. The wear behavior of SSFCW was measured using an HT-500 needle disc friction meter. The results show that TiC is preferentially formed in the alloy. It is primarily the nucleation core of a M7(C,B)3 (M mainly Cr and Fe) carbides; and when titanium is added to the wire, it reduces the amount of M7(C,B)3. When Ti is added, due to the formation of TiC, carbon is consumed, so that the microstructure of the alloy changes from hypereutectic to sub-eutectic. The addition of titanium to the iron-based SSFCW improves the abrasion resistance and corrosion resistance of the alloy, as well as the relatively high hardness and fine microstructure.

In this study, the high chromium cast iron wear resistant alloy was placed in alkaline solution with pH of about 14, and the corrosion behavior was studied by electrochemical corrosion technique. The effect of Ti on the microstructure and corrosion resistance of high chromium alloy surfacing layer was studied. The experimental results show that the titanium content has a great influence on the microstructure and mechanical properties of the surfacing alloy. In particular, titanium can significantly enhance the wear resistance of the surfacing alloy and enhance the corrosion resistance of the alloy. These results are related to the microstructure changes caused by different titanium contents. The increase in titanium content reduces the amount of carbides in the grain boundary and increases the amount of chromium dissolved in the iron matrix. So that high-chromium cast iron surfacing alloy has excellent toughness and strong corrosion resistance.

Higher titanium content reduces grain size and reduces carbide content. Corrosion resistance in alkaline media increases as the chromium content in the matrix increases.