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本文研究了HR3C钢在750℃下时效500 h前后的显微组织变化和第二相的种类.研究结果表明,时效后HR3C钢中的析出物主要为形状各异的M_(23)C_6和NbCrN,其中M_(23)C_6在晶界和晶内均有析出,NbCrN以极其细微的尺寸大量弥散分布于晶内;时效过程中弥散析出的M_(23)C_6和极其细微的NbCrN提高了HR3C钢的硬度.晶内及晶界析出的M_(23)C_6晶格常数均为基体的3倍,并与基体保持完全共格的关系,晶界处部分M_(23)C_6转变成了高Cr的σ相.
In this paper, the microstructural changes and the types of the second phase before and after aging at 750 ℃ for 500 h were studied.The results show that the precipitates in the HR3C steel are mainly M_ (23) C_6 and NbCrN , In which M_ (23) C_6 was precipitated both in the grain boundaries and in the grain, and NbCrN was dispersed in the grains in a very fine size. The M_ (23) C_6 and the extremely fine NbCrN precipitated during the aging increased the HR3C The lattice constants of M 23 C 6 crystal precipitated both in the grain boundary and in the grain boundary were all three times of that of the matrix and remained completely coherent with the matrix.The part of M 23 C 6 at the grain boundary transformed into high Cr σ phase.