高碳镀锌钢丝组织差异性精细表征研究

Research on Fine Characterization of Microstructure Difference of High Carbon Galvanized Steel Wire

实验表征并对比分析了国内外不同厂商钢丝的精细组织.结果表明:国产钢丝在夹杂物尺寸分布、镀锌层厚度、索氏体片层间距、渗碳体形态、位错密度等方面均与进口钢丝存在一定差距,即进口钢丝中当量直径<5μm的夹杂物所占比例高达90.6%,而国产仅分别为85.4%和88.0%;国产钢丝镀锌层中Zn-Fe合金层更厚,镀层更疏松;国产钢丝的索氏体片层间距更大,分布更分散.渗碳体溶解更加严重,颗粒状、短棒状的渗碳体颗粒数量和分布明显增多;国产钢丝的位错密度是进口钢丝位错密度的10倍.上述在微观组织上的差异导致国产钢丝的性能较差、质量不稳定.

The fine microstructure in high carbon galvanized steel wires from different manufacturers at domestic and abroad were experimentally characterized and compared.The results show that the microstructure of the domestic steel wires has apparently difference with that of the imported ones,in terms of the distribution of inclusion sizes,the thickness of galvanized layer,the spacing of sorbite lamella,cementite morphology,dislocation density,and etc.For instance,the percentage of the inclusions with the equivalent diameter less than 5μm can be up to 90.6%in the imported wire,compared with 85.4%and 88.0%in the domestic ones.The Zn-Fe alloy layer in the galvanized layer of the domestic wire is thicker and the coated layer is more loose.Moreover,the sorbite lamellar spacing of the domestic wire is larger and the distribution is more dispersed.It is also found that in the domestic wire,the dissolution of cementite is more serious,the number of granular and short-rod cementite particles increase significantly,and the dislocation density is 10 times than that of the imported one.The microstructural differences above lead to the poor performance and unstable quality of the domestic steel wire.