798 



BELL SYSTEM TECHNICAL JOURNAL 



of the two instruments agree on only about 15 per cent of the total, 

 and that in this case the differences are both positive and negative, 

 thus not permitting the application of a conversion factor. 



Experience data were also collected for Rockwell hardness and 



90 



80 



70 



60 



60 



-I» 40 



30 



20 



UPPER CURVE - AVERAGE EXPERIENCE 

 ON MATERIAL 0.040" 

 AND OVER THICK. 



LOWER CURVE -AVERAGE EXPERIENCE 

 ON MATERIAL LESS 

 THAN 0.040" THICK. 



POINTS REPRESENT 

 SPECIFICATION LIMITS 



LEGEND 



70000 80000 90,000 100,000 110,000 120,000 130,000 

 TENSILE STRENGTH— RSI 



Fig. 24 — Comparison of Curves of Results from Experience Data with Limits 

 Adopted, for Alloy B Nickel-Silver Sheet. 



tensile strength of the metals, the values being averages of tests on 

 individual shipments. 



Figure 22 shows graphically the data obtained on high and clock- 

 brass sheet, and Fig. 23 the experience data which have been averaged 

 and shown as a smooth curve for comparison with the specification 



