挤压铸造高速钢轧辊的研究

Study of Extrusion Casting High Speed Steel Roll

高速钢具有硬度高、红硬性好等特点 ,适合于制作轧辊、导辊等高温下工作的部件。高速钢轧辊通常采用离心铸造方法生产 ,由于高速钢中合金元素密度差大 ,轧辊偏析严重 ,高速钢优异的耐磨性发挥不出来。为了克服离心铸造方法的缺点 ,开发了挤压铸造高速钢轧辊技术 ,研究了挤压铸造工艺对高速钢性能的影响。压力、保压时间和压下速度是影响高速钢轧辊缩孔的重要因素。采用浇注温度 1 4 0 0～ 1 4 5 0℃、压力1 5 0 MPa、保压时间 1 2 0～ 1 5 0 s,压下速度 1 4～ 1 6 mm/ s,可获得组织致密、无偏析、加工量少的高速钢轧辊。应用于高速线材轧机预精轧机架 ,使用寿命比高镍铬无限冷硬铸铁轧辊提高 5～ 8倍。

High speed steel (HSS) has the characteristics of high hardness and good red hardness, is fit for the manufacture of parts working at high temperature such as roll, guiding roll, and so on. The HSS roll is usually manufactured by means of centrifugal casting, because of the density difference of alloy elements, roll segregation is very serious, segregation decreases roll wear resistance. In order to overcome above shortcomings, extrusion casting process is researched. The effects of extrusion casting process on the properties of HSS roll are researched, pressure, pressing time and pressing speed are three important factors affecting shrinkage cavity, as pouring temperature is 1400～1450℃, pressure is 150MPa, pressing time is 120~150s, pressing speed is 14~16mm/s, HSS roll having compact structure, no segregation and small working allowance is obtained. Using in high speed wire rod rolling mill, its service life is 6~9 times of high Nickel-Chromium infinite chill cast iron roll.