中文摘要：

采用金相分析及扫描电镜观察，研究了造成72A帘线钢抗拉强度偏低的主要原因。结果表明：80～120μm厚度的部分脱碳层对成品抗拉强度影响不大，由冷却工艺造成的索氏体化率偏低以及索氏体片层间距偏大才是造成72A帘线钢抗拉强度偏低的主要原因。

英文摘要：

The primary cause of 72A tire cord steel with low tensile strength was studied by metallographic analysis and SEM observation. The results show that the partial decarburization with a thickness of 80-120 μm has no effects on the tensile strength of the sample. The primary cause of 72A tire cord steel with low tensile strength is low sorbite rate and larger sorbite lamellar spacing.