大尺寸夹杂物对12MDV6铸件冲击性能的影响

Effect of large inclusion on impact toughness of 12MDV6 casting

以实际生产过程中12MDV6铸件冲击性能不稳定为背景,研究了大尺寸夹杂物对于12MDV6铸件冲击性能的影响。通过研究12MDV6铸件在冶炼全流程中夹杂物的变化过程,利用扫描电镜对夹杂物的特征进行分析,得出大尺寸夹杂物的产生位置,并提出改进工艺。结果表明,大尺寸的氧化物夹杂(Ca-Al-O+MgO、Al-O、Mg-Al-O)是导致12MDV6铸件冲击性能不合格的主要原因,夹杂物主要在AOD冶炼过程中生成。Al合金的大量添加来弥补AOD过程中的温度不足是导致大尺寸氧化物夹杂产生的直接原因。工艺改进方案主要包括减少AOD过程Al合金的添加量、提高电炉冶炼出钢时碳和硅元素的质量分数,以此弥补AOD冶炼过程中温度的降低。工艺改进后,铸件的冲击功在180 J以上,完全满足用户需求,实现了高效生产。

Based on the unstable impact toughness of 12 MDV6 casting during the actual production,the effect of large-size inclusions on the impact toughness of 12 MDV6 casting was studied.The formation process of large-size inclusion was obtained by studying the characteristics of inclusions analyzed by SEM during the smelting process of 12 MDV6 casting,and finally the corresponding improved process is proposed.The results are as follows.The large-size oxides,including Ca-Al-O+MgO,Al-O and Mg-Al-O,cause the unqualified impact toughness of 12 MDV6 casting,which are mainly formed during the AOD process.The heavy addition of Al alloy to compensate for the insufficient temperature in the AOD process is the direct reason for the formation of large-size oxides.The improvement process mainly includes two aspects,one is to reduce the amount of Al alloy added in the AOD process,the other is to increase the mass fraction of elemental carbon and silicon at the end of the electric furnace.The impact energy of the casting is above 180 J after the process is improved,meeting the needs of users.And the improved process can realize efficient production.