马氏体不锈钢酸洗溶液测定方法

Determination Methods of Ingredients in Acid Picking Solution for Martenstic Stainless Steel

对马氏体不锈钢酸洗溶液成分测定的化学分析方法进行了研究。结果表明：酚酞可以做马氏体不锈钢酸洗槽液中氢氟酸、硝酸的总量指示剂,用氢氧化钠标准溶液滴定得到。对于其中的氢氟酸,pH值在2.9~3.4范围内,以茜素磺酸钠做指示剂,用硝酸钍标准溶液滴定溶液中的氟离子。氢氟酸、硝酸的总量与氢氟酸含量之差即为硝酸的含量。氢氟酸测定的回收率在100.3%~101.9%之间,相对标准偏差为0.004%。硝酸测定的回收率在99.1%~101.3%之间,相对标准偏差为0.01%,实现了对马氏体不锈钢酸洗溶液的质量控制。

Chemical analysis methods of acid pickling solution of martensitic stainless steel were studied in detail.In acid pickling solution of martensitic stainless steel,the sum of hydrofluoric acid and nitric acid can be titrated by standard NaOH solution with phenolphthalein as the indicator.The content of hydrofluoric acid with pH ranging from 2.9 to 3.4 can be titrated by standard Th（NO3）4 solution with sodium alizarinsulfonate as the indicator.The content of hydrofluoric acid subtracted from the sum of hydrofluoric acid and nitric acid gives the content of nitric acid.In the determination of hydrofluoric acid content,the recovery rate is from 100.3% to 101.9%,and the relative standard deviation is 0.004%.In the determination of nitric acid content,the recovery rate is from 99.1% to 101.3%,and the relative standard deviation is 0.01%.The method is suitable for controlling the contents of nitric acid and hydrofluoric acid in acid pickling solution of martensitic stainless steel.