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对含铌0.051%的H13钢铸锭中一次碳氮化物成分特征及在1150℃、1250℃下的热稳定性进行了分析,并利用热力学软件Thermo-Calc对其形成机制进行了合理的解释。研究发现含铌0.051%的H13钢铸锭中存在3类一次碳氮化物,富Nb类、富V类以及富Mo-Cr类相。富Nb相热稳定性高,在1150℃及1250℃下保温6 h仍大量存在。富V相在1150℃下保温6 h仍然存在,而在1250℃下保温6 h即可完全固溶。富Mo-Cr相热稳定性低,无论是在1150℃还是1250℃下,均没有发现。这些相是在凝固过程中由于元素富集而在液相中析出。凝固过程中,富V的碳氮化物相首先析出,之后随着Nb含量的富集,富Nb的碳化物相开始析出,当Nb元素消耗到一定程度而同时V元素进一步富集后,富V的碳化物相再次析出,富Mo-Cr相在凝固末期最后析出。
The characteristics of primary carbonitride in H13 steel ingot containing 0.051% Nb and the thermal stability at 1150 ℃ and 1250 ℃ were analyzed. The formation mechanism of the carbonitride was explained by thermo-mechanical software Thermo-Calc. It is found that there are three types of primary carbonitride, Nb-rich, V-rich, and Mo-Cr rich phases in the H13 steel ingot containing 0.051% Nb. The Nb-rich phase has high thermal stability and still exists in large quantities at 1150 ℃ and 1250 ℃ for 6 h. The V-rich phase remains at 1150 ° C for 6 h, whereas it can be completely dissolved after 6 h at 1250 ° C. The low thermal stability of the Mo-Cr-rich phase was not observed at 1150 ° C or 1250 ° C. These phases are precipitated in the liquid phase due to elemental enrichment during solidification. In the solidification process, the V-rich carbonitride phase first precipitates, and then the Nb-rich carbide phase begins to precipitate as the Nb content is enriched. When the Nb element is consumed to a certain extent and the V element is further enriched, the V- Of the carbide phase precipitation again, the rich Mo-Cr phase in the final solidification precipitation.