The Grey Chronicles


1995-1999 NSC Prime Yield

NSC Prime Yield is also a function of input and output weights of materials processed in various mills; however, croppings and quality defects are subtracted for each processed material.

The same with Material Yield, NSC Prime Yields were also computed per processed coil for each processing line, but for the Quality Assurance monthly report, Material Yield was computed by comparing the HRC weight from Pickling Line No. 2 versus the output weight of the finished product—full hard or annealed coils (see Appendix C).

It should also be noted that in 1997, a Breakthrough Action Team for Yields Improvement was formed with Quality Assurance heads of various facilities of NSC plus a Union representative, as Area Champions. The team’s objective was to increase material and prime yields of various products using material-balance flowcharts. Mill abnormalities were analyzed for possible causes, and respective action plans were programmed for implementation.

The actual Prime Yield for each month, Figure 34, from January 1995 to December 1996 hovered less than the standard Prime Yield per month. Data shows that NSC production is very weakly correlated to the monthly Prime Yield.


Figure 34: NSC CRC Prime Yield vs. Production, 1995-1999 (Data: NSC)

Prime Yields on the last year of NSC’s production, Figure 34, were skewed to higher percentages because of smaller volume of production. Similar to the Material Yield, a shift was also visible starting January 1997 when the actual Prime Yields went beyond the standard Prime Yield. The 1997 Prime Yield Standard commitments (Que Estevez, 1997) were derived using the 1997 Material Yield commitments less the 1997 proposed maximum downgrading, which is based on the actual January to September 1996 downgrading, its root-cause analysis and occurrence reduction.


Que Estevez, Wilkie C.Jr. (1997), “Derivation of Cold Mill Material & Prime Yield Standards,” Internal Memo. Iligan: Quality Assurance, Cold Strip Mill, NSC. 01 April 1997. back to text


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