专用轧头外形如图1所示,它是采用CrWMn合金工具钢制造的。经淬火处理后,在使用过程中只轻轻一轧,尾部就断裂。实物断口晶粒粗细不一,图1中箭头1所指的尾部区域,断口呈粗大晶粒,而逐渐向上,箭头2所指的区域则晶粒变细。在尾部外圆表面,有黑色网纹分布在箭头3所指的区域。对三个区域进行金相分析如下: 1.箭头1区域的基体组织如图2所示,主要为极粗大的白色针状淬火马氏体和多量残留奥氏体(暗 Special head shape shown in Figure 1, it is made of CrWMn alloy tool steel. After quenching, the use of only a slight rolling, the tail is broken. In-kind fracture varies in grain size. In the tail region indicated by arrow 1 in Fig. 1, the fracture is coarse and gradually upward while the region indicated by arrow 2 is finer. On the outer surface of the tail, there are black lines distributed in the area indicated by the arrow 3. Metallographic analysis of the three regions is as follows: 1. The matrix organization of the arrow 1 region is shown in Fig. 2, mainly consisting of extremely coarse white acicular quenched martensite and a large amount of retained austenite