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采用药芯焊丝明弧自保护焊方法制备了含有2.0%~4.5%C、21%~23%Cr、1.5%~1.7%Si、0.2%~0.3%B(质量分数)的耐磨涂层,对其显微组织及耐磨性进行了表征,并考察了碳含量的影响。结果表明,其显微组织由γ-Fe+α-Fe+M7C3+M3(C,B)+Si5C3+Fe4N等组成。随碳含量提高,胞状富铬γ-Fe基体数量逐渐减小,直至消失,而位于晶界区域的硬质相体积分数增加。当碳含量为3.5%时,出现15~40μm六边形初生M7C3相颗粒,Fe4N相因石墨氧化形成保护气体量增加而下降。此外,湿砂耐磨性试验结果显示,堆焊涂层磨损为磨粒微切削机制为主,但无明显的塑性变形痕迹,其耐磨性不仅取决于其初生M7C3相数量,还与其共晶组织中二次M7C3数量和形态相关。
A wear resistant coating containing 2.0% -4.5% C, 21% -23% Cr, 1.5% -1.7% Si and 0.2% -0.3% B (mass fraction) was prepared by arc arc self- The microstructure and wear resistance were characterized, and the effect of carbon content was investigated. The results show that the microstructure consists of γ-Fe + α-Fe + M7C3 + M3 (C, B) + Si5C3 + Fe4N. With the increase of carbon content, the amount of cellular chromium-rich γ-Fe matrix gradually decreases until it disappears, while the volume fraction of hard phase located in the grain boundary region increases. When the carbon content is 3.5%, 15 ~ 40μm hexagonal primary M7C3 phase particles appear, and the amount of Fe4N phase decreases due to the increase of graphite gas. In addition, the test results of wet sand abrasion resistance show that the wear of surfacing coating is the main mechanism of abrasive micro-cutting, but there is no obvious plastic deformation. The wear resistance depends not only on the amount of primary M7C3 phase, but also on its eutectic Tissue secondary M7C3 number and morphology related.