Pipe quality evaluation using the Harrington’s desirability function

Abstract

The article considers one of the approaches to a comprehensive assessment of the quality of metal products, in particular, hot-formed pipes, using the Harrington`s function and desirability scale. The advantages and disadvantages of this technique are analyzed, ways to improve it are proposed, and the features of its application for cases of unilateral and bilateral restrictions imposed on quality indicators are considered. In the first case, it is proposed to introduce an additional parameter of the function, which enables to change its character depending on the pattern of variation of this property. For the case of bilateral restrictions, an assessment of the accuracy of the wall thickness of pipes 73×5.5 mm for the oil refining industry was made. One-sided limitations are illustrated by the processing of production data on the tensile strength of the metal of rolled pipes. It is noted that the choice of the parameters of the Harrington`s function is associated with a certain subjectivity, which can lead to significant errors in the estimates of various properties. The considered approach makes it possible to reasonably analyze the quality of products under production conditions on an unified scale, identify reserves for individual properties and suggest ways to improve technology in order to increase product quality.