METHOD FOR MEASURING RAPIDLY ALUMINUM SOLUBLE IN ACID IN STEEL

PURPOSE:To measure rapidly and exactly an Al content soluble in acid from the predetermined relation by allowing to contact each one end of a steel sample containing Al and a reference metal conductor to obtain a hot contact point and a cold contact point at the other end, and measuring the thermoelectromotive force produced by giving the temp. difference between both contact points. CONSTITUTION:In the measurement of the Al soluble in acid in steel added for deoxidation and austenite grain size control of steel, a circuit is formed between the sample 1 picked up by an opaque quartz tube and the reference metal conductor (pure copper) 2. Each one end is allowed to contact to make the contact part 3 as the hot contact point T2, and heated by a heater 4. The other end of the sample 1 is made as the cold contact point T1, and 1,000 deg.C temp. difference is given between the temp. T2 and temp. T1 to measure the thermoelectromotive force by a meter 5. The Al quantity can be detected rapidly by reffering the relation with the electromotive force obtained previously from the steel containing Al soluble in acid of the known quantity. In this way, the appropriate value of the Al quantity to be added can be determined rapidly at working site during steel making process.