METHOD FOR DISCRIMINATING MATERIAL QUALITY DETERIORATION OF ALLOY STEEL WITH AGE

摘要

PURPOSE:To non-destructively discriminate the material quality deterioration of an alloy steel with age with high reliability, high sensitivity and high accuracy by measuring the change of corrosion potential with age. CONSTITUTION:The alloy steel which is used at a high temp. and has the possibility of having the progressed embrittlement is used as an object to be discriminated and the change of the corrosion potential thereof with age is measured. The measurement of the corrosion potential is executed by using a calomel electrode or silver/silver chloride electrode, etc. as a reference electrode system 6, immersing the alloy steel to be measured in an electrolyte 2 and measuring the potential thereof with a potentiometer 18. The electrolyte is selected from the electrolytes which exhibit selective corrosiveness to the embrittled point of the alloy steel. A micro-electrode 3 having about 5-50mum inside diameter at the top end is used as the capillary tube in the reference electrode system 6. The measurement by bringing such electrode as near to the test material 1 as possible is preferable as the dissolution behavior of the alloy steel surface appears exactly in the fluctuation of the corrosion potential. The corrosion potential fluctuates more largely with the alloy steel having the more progressed embrittlement and therefore, the degree of the embrittlement of the alloy steel is immediately discriminated if such fluctuation condition is analyzed.