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研究了深冷和去应力处理对D2冷作工具钢回火碳化物析出的影响。深冷处理温度为-196℃,保温时间分别为2 h、24 h和30 h;去应力处理工艺为130℃×90 min。所有试样都与经常规工艺热处理的试样作了对比。采用金相分析、X-射线衍射(XRD)和温差电势法研究了经深冷和去应力处理的试样。除了OM外,还选用了扫描电镜(SEM)和场发射扫描电镜(SEM-FEG)进行微观组织表征。结果表明,经深冷或去应力处理的试样中二次碳化物(微米级)析出未发生变化。经深冷处理但未经去应力处理的试样基体中,回火二次碳化物(纳米级)比较细小而弥散。回火二次碳化物的细化可能是回火过程中碳化物的原位析出所致。
The effects of cryogenic and de-stressing treatments on the tempering of tempered carbides in cold work tool steel D2 were studied. Cryogenic treatment temperature of -196 ℃, holding time were 2 h, 24 h and 30 h; to stress treatment process is 130 ℃ × 90 min. All samples were compared with those of conventional heat-treated samples. Metallographic analysis, X-ray diffraction (XRD) and temperature difference potential method were used to study the cryogenic and de-stressing specimens. In addition to OM, SEM and SEM-FEG were selected for microstructure characterization. The results show that there is no change in the precipitation of secondary carbides (micron level) in the samples treated by cryogenic or de-stressing. After cryogenic treatment but without stress treatment of the sample matrix, the tempering secondary carbide (nanoscale) is relatively small and dispersed. Tempering of secondary carbide refinement may be during the tempering carbides in situ precipitation.