STATISTICAL PROCESS CONTROL CHARTS APPLIED TO OPTIMAL QUALITY IMPROVEMENT FOR STEELMAKING PROCESSES | ||||
| ERJ. Engineering Research Journal | ||||
| Article 8, Volume 28, Issue 2, April 2005, Page 185-198 PDF (1.19 MB) | ||||
| Document Type: Original Article | ||||
| DOI: 10.21608/erjm.2005.69944 | ||||
 View on SCiNiTO | ||||
| Authors | ||||
| M. A. Sharaf El-Din1; M. M. El-Khabeery1; H. I. Rashed2 | ||||
| 1Production Engineering and Mechanical Design Dept., Faculty of Engineering Minoufia University, Shebin El-Kom, Egypt. | ||||
| 2ARC0 Steel, Sadat City, Minoujya, Egypt, | ||||
| Abstract | ||||
| The complex nature for steelmaking processes makes the classical Statistical Process Control (SPC) methodologies are optimal when used to monitor and control steam boiler generation used to supply the required steam for vacuum degassing processes. These processes include a large number of variables that need to be monitored and controlled, while classical SPC requires a control chart for each variable. Thus the effect of one variable can be confounded with effects of other correlated variables. Such a situation can lead to false alarm signals. Univariate control charts are also difficult to manage and analyze because of the large numbers of control charts of each variable. An alternative approach is to construct a single multivariate control T2 chart that minimizes the occurrence of false process alarms as well as monitors the relationships between the variables, and identifies real process changes not detectable using univariate charts. It is necessary to simultaneously monitor and control these variables to achieve optimal vacuum degassing process performance to remove harmfid gases from the molten steel before casting. This represents the main concern of the presented paper. This paper also studies the application of univariate and multivariate control charts in the field of steel industry. The performance analysis for each one is studied using the Average Run Length (ARL). A comparison of the univariate out-of-control signals based on the multivariate out-of-control signals is also made to illustrate the efficiency of the Hotelling's T' statistics. | ||||
| Keywords | ||||
| Statistical Process Control (SPC); Univariate Control Charts; Multivariate Control Techniques; Hotelling's statistics; Average Run Length (ARL) | ||||
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