炉前全氧测定钢样制备方法探讨

影响炉前钢样全氧含量检测准确性的因素较多,以前的研究多集中于分析方法的建立以及样品的前处理等方面,而对样品制备方面的探讨较少。试验探讨了对炉前钢样在车削过程中是否加冷却液、样品表面粗糙度、以及是否锻造对全氧分析结果的影响,并提出了切实可行的解决方案。通过将样品加工为不同粗糙度等级并进行全氧含量分析,扫描电镜在放大相同倍数的情况下表征未经锻造工艺加工的样品、经锻造工艺加工的样品以及标准样品的内部形貌,同时分析锻造工艺对样品均匀性的影响,将分析结果与国标方法的精密度比较,未见样品表面粗糙度在小于6.0 μm的情况下对检测结果的影响,而锻造工艺对全氧分析结果的稳定性存在影响,未经锻造加工和经锻造加工样品的相对标准偏差(RSD,n=9)相差13.6%,通过实验确定了测定全氧的样品需保证表面氧化皮去除干净并经锻造工艺后,氧分析结果稳定,可信度高。

Discussion on steel sample preparation method for bath analysis of total oxygen

The determination accuracy of total oxygen content in steel sample in bath analysis is affected by many factors. The previous studies were mainly focused on the establishment of analysis method and the pretreatment of sample, but there were few discussions on the sample preparation. In this paper, the influence of adding cooling liquid or not, the surface roughness and forging or not in turning process of steel sample on the analytical results of total oxygen was investigated and discussed. The feasible solutions were proposed. The samples were processed to different roughness levels for analysis of total oxygen content. The internal morphologies of standard sample and samples with and without forging treatment were characterized using scanning electron microscope with same magnification. Meanwhile, the effect of forging process on sample uniformity was analyzed. The measurement results were compared with the precision of national standard method. It was found the determination results were not influenced when the surface roughness of sample was less than 6.0 μm. However, the stability of analysis results of total oxygen was affected by the forging process. The relative standard deviation (RSD, n=9) different between the samples with and without forging treatment was 13.6%. The experiments results indicated that the surface scale should be cleaned followed by forging for the determination of total oxygen content. The analytical results of proposed method were stable with high reliability.