直读光谱法测定钢铁中常规元素结果准确性的探讨

On the Accuracy of Analytical Results of the Common Elements in Iron and Steel Obtained by Direct-reading Spectrometry

为提高ARL 4460直读光谱仪测定钢铁中8种常规元素分析结果的准确性,对一些主要的影响因素特别对碳及硫量测定的影响因素做了试验,并对其结果作了探讨,从中得到了一些有利于提高测定准确性和精密度的方法和措施,主要有以下几点:①改变了仪器出厂时设定的光源参数(冲洗时间由10s降为2s,预燃时间由7s降为6s,曝光时间由8s降为3s);②测定碳、硫、磷须用99.999%的高纯氩,且应控制其压力在0.30 MPa左右;③试样表面要干净平整,纹路清晰,应用细砂砂轮机处理试样表面;④制备定碳样品时,样品温度不能高于40℃,且保持其起始状态的纹路粗细程度;⑤分析室环境温度应保持恒定(25℃左右),每8h进行一次工作曲线的校正;⑥测定硫的试样若温度过高,宜先将其冷却至接近室温再作分析,且在分析时应至少取3个分布均匀的激发点,且需根据试样特点作现场校正曲线,用控制试样进行类型标准化。

Aiming to raising of accuracy of analytical results of 8 common elements in iron and steel by the ARL 4460 direct-reading spectrometer,testing for some influential factors,especially for determinations of carbon and sulfur,was made.The following measures were found to be effective for improving both the accuracy and precision of the determinations： ① light source parameters set during manufacturing were modified by lowering the time of development from 10 s to 2 s,the time of pre-ignition from 7 s to 6 s,and time of exposure from 8 s to 3 s;② for the determination of C,S and P,high-purity argon（99.999%） with its pressure of 0.30 MPa,should be used;③ a fine grinder should be used in preparing sample in order to make the surface of sample clear and plain,as well as to have clear grain;④ in determination of carbon,temperature of sample should be kept below 40 ℃,and to keep the finess of its grain in its original state;⑤ room temperature of the lab should be kept constant around 25 ℃,and correction of working curves should be made every 8 h;⑥ in determination of sulfur,samples with relatively higher temperature should be cooled to near room temperature before analysis,and at least 3 evenly deposited excitation sites should be taken as well as correction and standardization of the standard working curve should be made.