基于精密度共同试验,采用图方法和数值计算方法,对旋转挂片法测定水处理剂对20号碳钢试片在海水中的缓蚀性能的测试数据进行了统计学分析,估算该法的精密度.结果表明,参加试验的5家实验室所获得的92组腐蚀率测试数据经一致性和离群值检验,只在检出水平(α=0.05)下出现3组岐离值,但未发现离群值,说明数据有效.方法的精密度可以表示为:碳钢腐蚀率在0.456~0.490 mm/a时,重复性标准差sr=0.005 1,重复性限r=0.037;再现性标准差sR=0.078 7,再现性限R=0.045.该法的精密度与总平均值m之间没有统计学意义上的依赖关系.应用该方法测得杀生剂SW303在海水中对20号碳钢具有缓蚀性能,且碳钢缓蚀率和药剂浓度间具有良好的线性相关性(r=0.966 9,p＜0.01).

In order to estimate the precision of rotary hanging piece method for determining the corrosion inhibition performance of water treatment agent on 20# carbon steel in seawater,the data from precision common tests were statistically analyzed using the graph and numerical methods.The consistency and outliers of 92 data from five laboratories were investigated.The results indicated that there were only 3 stragglers but no statistical outlier was detected,which showed that 92 data were valid.The method precision can be expressed as follows: the repeatability standard deviation and the repeatability limit were 0.005 1 and 0.037 respectively,and the reproducibility standard deviation and the reproducibility limit were 0.078 7 and 0.045 respectively when testing corrosion rate between was 0.456 mm/a and 0.490 mm/a.There is no statistically significant correlations between the method precision and the oven mean.It is proved by using the rotary hanging piece method that Biocide SW303 had corrosion inhibition performance on 20# carbon steel in seawater.The linear correlation coefficient was 0.966 9 between the corrosion inhibition rate of carbon steel and SW303 concentration (p＜0.01).