DT4E电磁纯铁真空退火磁性能不合格的分析和改进

Analysis and improvement of unqualified magnetic properties of vacuum annealed DT4E electromagnetic pure iron

某DT4E电磁纯铁零件真空退火后存在矫顽力超出设计要求的问题。针对此问题,对DT4E电磁纯铁进行了860~1150℃×4 h真空退火处理,研究了退火温度、磁性能测试试环尺寸以及原材料中杂质成分对其磁性能的影响。结果表明,随着退火温度的升高,磁感应强度B2500的变化呈“M”型,矫顽力Hc呈“V”型变化,最大磁导率μm与矫顽力Hc的变化趋势相反。最佳的真空退火温度为900℃,此时磁感应强度B2500为1.63 T,矫顽力Hc为25.19 A/m,最大磁导率μm为23.64 mH/m,满足设计要求,且磁环试件的规格尺寸对DT4E电磁纯铁磁性能的测量结果没有明显影响。原材料中杂质元素的含量对磁性能影响较大,当C含量较高时,磁导率下降,矫顽力升高,容易导致磁性能不合格。

Coercivity of a DT4E electromagnetic pure iron part after vacuum annealing exceeds the design requirements. In order to solve this problem, the DT4E electromagnetic pure iron was vacuum annealed at 860-1150 ℃ for 4 h to analyze the effects of annealing temperature, magnetic test ring size and impurity compositions in raw materials on the magnetic properties. The results show that with the increase of annealing temperature, the magnetic induction intensity B2500changes as “M” type, the coercivity Hcchanges as “V” type, and the change trend of maximum permeability μmis opposite to that of the coercivity. The optimum vacuum annealing temperature is 900 ℃,at which the magnetic induction intensity B2500is 1.63 T, the coercivity Hcis 25.19 A/m, and the maximum permeability μmis 23.64 mH/m, all meeting the design requirements.Moreover, the size of the magnetic test ring has no significant effect on the measurement results of the magnetic properties of the DT4E electromagnetic pure iron. The content of impurity elements in raw materials has a great influence on magnetic properties. When the C content is higher, the permeability decreases and the coercivity increases, which easily leads to unqualified magnetic properties.