摘要
某预应力钢丝生产厂在使用Φ12.5mm的77MnCr盘条生产Φ7.0mm的螺旋肋预应力钢丝时,常在拉拔过程中发生断线的现象。针对该问题,利用光学显微镜、扫描电镜和能谱仪对77MnCr盘条在冷拉拔过程中产生笔尖状断口的断裂试样进行了系统检测和分析。检验结果表明,试样中心部位存在的"V"形裂纹是造成盘条在拉拔过程中产生断裂的裂纹源。经分析得出V形裂纹的形成与盘条心部存在的网状渗碳体有关,而网状渗碳体的产生与连铸坯中心偏析,尤其是碳偏析和盘条轧制过程中的冷却速度有着十分紧密的关系。
Wire breakage often occurred in wire drawing when one prestressed wire manufacturer produced Φ7.0 mm spiral ribbed prestressed wire with Φ12.5 mm 77MnCr wire rod.In order to settle this problem,systematic inspection and analysis were conducted on the sample taken from broken 77MnCr wire with pencil-tip type fracture by means of optical microscope,scanning electron microscope and energy dispersive spectrometer.Inspection results show V shape crack in sample center is the crack source for wire breakage in drawing.It is found that the formation of V shaped crack is corresponding with network cementite in rod center,which is closely related to billet central segregation(esp.carbon segregation) and cooling speed in rod rolling.
出处
《天津冶金》
CAS
2012年第4期47-49,62,共3页
Tianjin Metallurgy
