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本文就某些合金元素Mo和Mn加入到NiCrMoV转子钢中对回火脆性敏感性的影响进行了研究。当加入0.3％Mn以后,该钢的塑脆转变温度(FATT)在所有的时效时间都比不含Mn的相同钢大约提高了一倍。尽管Mn-P有某种共偏聚效果,但FATT的提高主要与Mn本身对晶界结合强度的固有影响以及P的脆化能力提高有关。 比较NiCr转子钢和NiCrMoV转子钢的杂质导致的脆性行为,根据FATT的测定就可清楚地看到Mo的有益贡献。试验结果显示了Mo的清扫剂作用,在体内Mo-P的交互作用而抑制了脆性,Mo与P在晶界的共偏聚从而降低了磷的脆化能力。本文还报告了在长时时效时碳化物中富集磷的试验结果。
In this paper, some alloying elements Mo and Mn added to the NiCrMoV rotor steel on the impact of temper embrittlement sensitivity were studied. When 0.3% Mn is added, the plastic’s ductile transition temperature (FATT) of the steel approximately doubles over all the aging time compared to the same steel without Mn. Although Mn-P has some effect of co-segregation, the increase of FATT is mainly related to the intrinsic influence of Mn itself on the strength of grain boundary bonding and the increase of P’s embrittling ability. Comparing the brittle behavior caused by the impurities of NiCr rotor steel and NiCrMoV rotor steel, the beneficial contribution of Mo can be clearly seen from the measurement of FATT. The experimental results show that the effect of Mo as a cleaning agent is that the Mo-P interaction in the body inhibits the brittleness, and the co-segregation of Mo and P at the grain boundaries reduces the phosphorus embrittlement ability. This paper also reports the experimental results of phosphorus enrichment in carbides during long-term aging.