METHOD FOR EVALUATING THE RELIABILITY OF STEEL AND STEEL OF HIGH RELIABILITY OBTAINED ACCORDING TO THE SAME METHOD

摘要

A method for evaluating the reliability of a steel in relation to small and medium size inclusions as well as large inclusions, and high reliability steel obtained by this process. The method makes it possible to evaluate the reliability of a steel in terms of inclusions, and it is characterized in that one evaluates the inclusions whose maximum size is close to 100 mum at the most by microscopy combined with the statistical analysis of the extreme values; inclusions up to a maximum size of 100 mum or more shall be evaluated by ultrasonic flaw detection test at a frequency in the range of 5 to 25 MHz; and the reliability of the steel is evaluated on the basis of the results of the statistical analysis of the extreme values applied to the combined results of the microscopy and ultrasonic flaw detection test.