SWRH82B盘条使用中脆断的原因分析及防治

Cause Analysis and Prevention of Brittle Fracture of SWRH82B3WireRodinUse

采用体式光学显微镜、金相显微镜、化学成分分析、扫描电子显微镜、电子能谱、显微硬度,分析了82B盘条在使用过程中出现的杯锥状断口、放线头尾脆断和拉拔斜茬状断口的三种典型断口特征。结果表明,杯锥状断裂的主要原因是盘条中心严重的成分正偏析和控冷不当使心部形成网状渗碳体所致;放线脆断和斜茬状断口均因碰撞、刮擦等外界原因导致表面形成硬脆的形变马氏体。针对三种典型断口分别提出了具体的工艺改进措施,能够有效降低SWRH82B盘条发生上述脆断的几率。

Using stereo light microscope,metallographic microscope,chemical composition analysis,scanning electron microscope,electron spectrum and microhardness,three typical brittle fractures of SWRH82B wire rod during use were analyzed,including cup cone fracture,head and tail brttle fracture on pay-off bobbin and oblique stubble fracture.The results show that the main reason for the cup-cone fracture is serious positive segregation of the composition in the center of the wire rod and improper cooling control,which causes the core to form a network of cementite.Brittle fracture and oblique stubble fracture are all caused by the formation of hard and brittle deformed martensite on the surface due to violent collisions,scratches and other external effects.Specific process improvement measures were proposed for three typical fractures,which can effectively reduce the probability of the above-mentioned brittle fracture of SWRH82B wire rod.