利用氧氮仪日常质控数据计算钢中氮测量精密度

Calculation of measurement precision of nitrogen in steel by using daily quality control data of oxygen-nitrogen analyzer

精密度是钢铁成分分析数据能否被接受的重要判定依据。现有国家标准所列精密度就碳素钢及低合金钢分析而言是一种基本要求,对于一些特定的钢铁产品则可能存在一定的局限性,对此,实验室应针对自身检验流程,应用专业的统计方法,计算出相应的精密度。为了提高效率,实验并未组织新的精密度试验,而是充分利用已有日常质控数据,按照GB/T 6379的要求,取新旧程度不同的ON-836和TC600两台氧氮仪测量质控标准样品GBW01401a和498的60组数据进行计算,得出其重复性限、室内再现性限,数据接近或优于国家及行业标准。所得精密度已应用于实验室生产应用和测量系统分析。为有针对性地开展实验室日常质量控制,提出了将室内再现性细分为室内仪器再现性限和室内日间再现性限的建议,使两台仪器间的分析数据是否可以接受有了判定依据。

The measurement precision is an important criterion to judge whether the analysis results of components in steel are acceptable or not.In current national standards,the measurement precision is a basic requirement for the analysis of carbon steel and low alloy steel.Certain limitations may exist for some specific steel products.Therefore,the corresponding precision should be calculated in the laboratory using professional statistical methods according to the inspection process.In order to improve the efficiency,new precision tests were not conducted in the proposed study.Instead,it took full advantage of the existing routine quality control data.According to the requirements of GB/T 6379,total 60 groups of measurements results of standard samples(GBW01401a and 498)for quality control by two oxygen-nitrogen analyzers(ON-836 and TC600 with different degrees of new or old)were used for calculation.The repeatability limit and indoor reproducibility limit were obtained,which were close to or even better than the national and industrial standards.The resultant precisions have been applied for the laboratory production and measurement system analysis.In order to carry out the routine quality control in laboratory specifically,the classification of indoor reproducibility limit into indoor instrument reproducibility limit and indoor daytime reproducibility limit was suggested.Therefore,there was basis to judge whether the analysis results of two instruments were acceptable or not.