基于应变设计X70M钢落锤断口成因分析

摘要

In this article, the special morphology of X70M DWTT fracture based on strain design material was analyzed by means of metallographic structure analysis and energy spectrum analysis. The results showed that the hard and soft phase structure of the above material distribute unevenly, and a large number of segregation of Nb, Ti and Mn exist in wall thickness center banded structure. Under the condition of large tear force, the material started to crack from banded structure and extended along the hard phase bainite organization. Because a large number of fine grained polygonal ferrite existed in material interior, so it is with good toughness, the crack arrest can be received effectively, and formed special DWTT fracture morphology.%采用金相组织分析及能谱分析等方法对基于应变设计材料X70M落锤断口特殊形貌进行了研究分析。分析结果表明，该种材料的硬相及软相双相组织分布不均匀，且壁厚中心带状组织区域存在大量Nb， Ti和Mn的偏聚，在受到较大撕裂力的情况下，材料从带状组织区域起裂，并沿硬相贝氏体组织扩展，但由于材料内部具有大量细晶粒的多边形铁素体组织，因此整体韧性较好，能够得到有效的止裂，于是形成了特殊的落锤断口形貌。