红外吸收法测定钢铁中碳含量的不确定度

Uncertainty in measurement of carbon content in steel by infrared absorption method

采用红外吸收法测定钢中碳含量,对影响测定结果不确定度的各个因素如测量重复性、标准物质校准仪器的变动性、标准物质示值的不确定度、天平称量的不确定度、仪器分辨率引起的不确定度分量进行了评定,计算了相对合成标准不确定度和扩展不确定度。评定结果表明,在多次校准的前提下,标准物质校准仪器的变动性和标准物质示值的不确定度对总不确定度影响最大,其次是测量重复性。所以,在测定中应特别注意标准物质的选择和标准物质对仪器校准的变动性。

The content of carbon in steel was determined by infrared absorption method . The factors influencing the uncertainty of determination results were analyzed , such as measurement repeatability , calibration movability , certified values , weight of sample , instrument resolving power .The relative synthesis standard uncertainty and expanded uncertainty were calculated .The results show that after multiple calibrations , the uncertainty of determination results is mainly from the calibration movability and the certified values , and then is from the measurement repeatability .So, in the determination, choosing the right certified reference material and the stability of the instrument must be pay more attention .