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前言钢线在拉拔成不同规格钢丝之前,首先要经过热处理炉进行930℃加热,待烧透,然后通过60厘米厚的木炭粉保温层进入500～550℃的铅浴锅进行等温淬火。将上述热处理过的钢线进行拉拔,通常要经过七道模具,为第一次拔丝成品完成。在生产中经常出现拉拔到第三、四道模子产生钢线断裂。为寻求原因,对生产拉拔断裂的试样及不同时间停车试验后的热处理钢线,拉拔产生断裂的断口及微观组织进行比较。一、生产缺陷样的检查 1.断口形貌生产拉拔到第三、四道次断裂的钢线断口都为正负一对。断口心部属正拉断型为等轴韧窝结构,边部受剪切力和挤压力为抛物线型韧窝,如图1所示。
Preface The wire before drawing into different specifications of the wire, the first to go through the heat treatment furnace 930 ℃ heating, to burn through, and then through the 60 cm thick charcoal powder insulation into the 500 ~ 550 ℃ lead bath isothermal quenching. The above heat-treated steel wire drawing, usually through the seven molds, for the first finished wire drawing finished. Often appear in the production of drawing to the third, four molds have a steel line fracture. In order to find out the reasons, the tensile fracture and the microstructure of the sample produced by tensile fracture and the heat treatment steel wire after stopping test at different times were compared. First, the production of a defect-like inspection 1. Fracture appearance Production drawing to the third, four times the fracture of the steel line are positive and negative pairs. Broken heart is a positive pull-off type for the equiaxed dimple structure, the edge of the shear force and squeeze the parabolic dimple, as shown in Figure 1.