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研究了混合稀土金属对Cr-Mn-N奥氏体耐热钢的组织结构、硬度、时效韧性和高温强度的影响。发现在650～8500℃时效过程中,Cr-Mn-N 钢有三种类型沉淀:碳化物与新生奥氏体组成的晶界沉淀,碳化物的普遍沉淀和Ⅹ相。稀土元素能促进这三类沉淀的发展,而对第一种沉淀影响尤著。时效后钢的硬度随钢中稀土元素含量的增多而升高。时效后钢的韧性和600-750℃的持久强度有相同的变化规律,最初随着稀土元素含量的增多而升高,达到一个最大值后,就逐渐降低。韧性和强度两个曲线上的最大值分别对应于稀土元素含量为0.0015%和0.013%。根据稀土元素在钢中的作用及其分布情况,对钢的性能变化作了初步解释。
The effects of mixed rare earth metals on the microstructure, hardness, aging toughness and high temperature strength of Cr-Mn-N austenitic heat-resistant steel were studied. It is found that there are three types of Cr-Mn-N steels in the aging process from 650 ℃ to 8500 ℃: grain boundary precipitation consisting of carbide and newborn austenite, precipitation of carbides and phase X. Rare earth elements can promote the development of these three types of precipitation, but especially the first precipitation. After aging, the hardness of steel increased with the increase of rare earth elements in steel. After aging, the toughness of steel and the persistence strength of 600-750 ℃ have the same changing rule, and initially increase with the increase of REE content. After reaching a maximum, the toughness decreases gradually. The maximum values on the two curves for ductility and strength correspond to 0.0015% and 0.013%, respectively, of the rare earth elements. According to the role of rare earth elements in steel and its distribution, the performance of steel was initially explained.