Промышленная инженерия и менеджмент

Statistical Quality Control of Chemical Compositions of Rolled Products: A Case Study of the Light Section Mill of Ajaokuta Steel Company Limited

Abstract

Ocheri Cyril, Onyeji Lawrence Ibe, Ojonimi Ile Theophilus

Statistical Quality Control (SQC) analysis deals with quantitative data; it is also a scientific method of analyzing masses of numerical data so as to summarize the essential features and relationship of data in order to generalize from the analysis pattern behaviour, particular outcome or future tendencies. This research work focused on the use of statistical quality control to determine the behaviours of the determined chemical compositions of rolled products from the Light Section Mill of the Rolling Mills of the Ajaokuta Steel Company Limited with a view to detecting and eliminating non -random (sporadic) variations in production process. The process monitored the performance of the chemical compositions of rolled products of medium carbon steel on a daily basis during the period of production from 29/04/06 to 29/05/06 for the production of rods from the Light Section Mill (LSM). The analyzed samples and data collected for critical characteristics were determined to ascertain if they shifted away from the purely random pattern (specified compositions). Ten samples were collected from the rolled products from the mill and were analyzed with a SPECTRO Analytical Instrument in the Quality Control and Materials Analysis in the Foundry Shop of the company, where the chemical compositions were determined as shown on the tables and they were also used to plot graphs for better understanding. Two control charts ( and )were used to determine the performance and to indicate if the process remained in control and whether there are variations, these will serve as early warning system for information to the production engineers, the quality control officers and management of the mill that something odd has probably happened to the production process.