球墨铸铁铝锭模具材料热处理工艺的选择

The Choice of Heat Treatment Process of Ductile Iron Mould for Al Ingot

在普通球铁中增加适量硅元素来提高球铁的共析转变温度,改善其组织及性能,以达到铝锭模具对性能的要求。但这种球铁材料直接用于生产后会较早地出现热疲劳裂纹,并由于裂纹的扩展而导致模具失效。因而考虑通过设计优化热处理工艺来提高材料的性能。针对于此,在实验中设计了两套热处理工艺方案,并参考材料的综合力学性能指标,以均匀化组织、延缓热疲劳裂纹的萌生、降低裂纹扩展速度为目的进行选择。最终对比实验研究表明,经第一套热处理方案处理后的铝锭模具材料,其综合性能得以提高,组织达到铝厂的要求,在实际生产中有效地延长了铝锭连铸机浇铸模具的使用寿命。

Appropriate-silicon element has been added into ordinary ductile iron for increasing eutectoid transformation temperature,improving microstructure and properties for performance requirements applied to mould for Al ingot however, when this ductile iron used in mould for Al ingot production, thermal fatigue cracks would occur in the early stage and then crack growth would break down the mould hence to consider an optimizing heat treatment process to improve performance of material was needed. With reference to material mechanic properties two types of heat treatment process upon the purpose of homogenizing the microstructure, puting off the thermal fatigue crack initiation and decreasing the propagation rate of fatigue crack have been chosen and designed. The comparison with experiment research between the two types of heat treatment process showed that the ductile iron that treated by the first heat treatment had obtained satisfactory overall performance, desired metallographic structure. In the production the Al ingot casting machine had improved its performance and service life to a large extent.