Defects and Incompatibilities of Pipes Manufactured by Pilgrim Method

Abstract

Abstract The increase in the quality requirements for the pipes and the increasing needs to reduce production costs, while increasing the efficiency of the process in market of hot rolled pipes are observed. One of the cost reduction factors is the reduction of the number of defects by early detection and, if possible, the removal of non-conformities. Incompatibility is an error that can be removed in accordance with the performance standard that does not cause defects (Norma API). The defect is imperfection that is so important that it is the basis for the removal of the product or its part based on the criteria set out in the performance standards. In pipe manufacturing processes, defects and batch incompatibilities can be distinguished, which arise in the steelworks during metal solidification and roll forming in the course of metal processing. The defect may also arise as a result of removing steel material or result from rolling processes defects. The paper presents the analysis of the process of quality control of pipes manufactured using the pilgrim method on the basis of real process data. The analysis were involved 1070 pieces of ingots from 11 different melts for rolling pipes. At various stages of production, discrepancies and defects were revealed, which were caused by metallurgical or technological defects associated with rolling pipes. The total amount of discrepancies and defects eliminated 168 pieces of finished pipes. The aim of the work is to show that by means of appropriately selected methods of eliminating imperfections, it is possible to increase the efficiency of the manufacturing process.