ASSESSMENT OF STATISTICAL STABILITY OF STEEL STRIP HOT-ROLLING PROCESS

Statistical methods belong to the basic quality tools. Among statistical instruments the statistical process control SPC takes particular place. One of the principal tasks of SPC is monitoring of a process by means of control charts. They are first of all Shewhart's control charts. The aim of investigations was to assess stability of technological process of hot-rolling of steel strip. There were available the results of thickness measurements madę with an X-ray thickness gauge as well as measurements of convexity and wedge shape made with a profile measurement gauge. The assessment of statistical process stability was performed by means of Shewarfs control charts technique. In case of thickness the estimation of capability indices Cp, Cpk and Pp, Ppk have been carried out, in addition