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带状组织是铸坯热轧过程中形成的常见组织缺陷,严重影响钢材后续加工性能和使用性能。对常见亚共析钢带状组织的形成机制、危害、控制措施和评级方法等研究现状与认识进行系统评述。分析认为,合金元素微观偏析是形成带状组织的根本原因,合理地控制合金成分、枝晶形态和热加工工艺也是抑制带状组织的重要途径。由微观偏析导致的枝晶内和枝晶间Ar3转变温度差异越大,带状组织越易形成。奥氏体分解过程中的冷却速率和奥氏体晶粒尺寸是形成带状组织的主要影响因素。较高的冷却速率、较大的奥氏体晶粒尺寸均会抑制带状组织发生。还分别阐述一次、二次碳化物对过共析钢带状组织形成的主要作用。同时,提出促进合金元素均匀扩散、减少连铸坯凝固组织微观偏析是减轻或消除带状组织的主要途径。带状组织中可能存在长条状夹杂物,然而,钢中夹杂物的大小、形貌和分布对带状组织的影响程度至今还不清晰。精细地表征与定量评价带状组织及其危害程度是亟待开展的重要工作。此外,铸坯加热制度对消除带状组织和控制组织晶粒度的综合影响也有待深入认识。
The ribbon structure is a common tissue defect formed during the slab hot rolling, seriously affecting the steel’s subsequent processing performance and serviceability. This paper systematically reviews the research status and understanding of the formation mechanism, hazards, control measures and rating methods of common hypo-eutectoid steel bands. The analysis shows that micro-segregation of alloying elements is the fundamental reason for the formation of banded structure. The reasonable control of alloy composition, dendrite morphology and thermal processing is also an important way to suppress banded structure. The greater the difference in Ar3 transition temperature between dendrites and dendrites due to microsegregation, the easier the ribbon structure is formed. The cooling rate and the austenite grain size during the austenite decomposition are the main influential factors for the formation of banded structure. Higher cooling rates and larger austenite grain sizes inhibit banding. Also described separately, the second carbide on the eutectoid steel strip formation of the main role. At the same time, it is proposed to promote the uniform diffusion of alloying elements and reduce the microstructure segregation of solidified slab, which is the main way to reduce or eliminate the banded structure. However, the influence of the size, morphology and distribution of inclusions in steel on the banded structure is still unclear. The detailed characterization and quantitative evaluation of banded tissues and their harmfulness are important tasks to be carried out urgently. In addition, the slab heating system to eliminate the banded and control the grain size of the integrated impact remains to be fully understood.