SHEET NON-FERROUS METALS 



773 



series retested using standard blocks. There have been no changes 

 in tensile strength limits. Figure 19 shows Rockwell hardness plotted 

 against tensile strength, for high and clock brass, the individual point 

 representing determinations of Rockwell hardness and tensile strength 

 on commercial shipments of material. The lines drawn show the 

 grouping of the data according to thickness. 



Alloys C and D Brass Sheet: 



The chemical composition limits for alloys C and D brass sheet 

 are given in Table VI. 



Alloy E Brass Sheet: 



Four rolling series were made from one bar of metal having the 

 analysis shown in Table VII. These series begin at B. & S. gage Nos. 



TABLE VII 

 Chemical Analyses of Rolling Series 



Copper, per cent 



Lead, per cent 



Iron, per cent 



Zinc, per cent 



Nickel, per cent 



Manganese, per cent .... 



Tin, per cent 



Phosphorus, per cent .... 



Graphite, per cent 



Combined Carbon, per 

 cent 



Alloy C 



Phosphor 



Bronze 



91.84 

 0.02 

 0.03 

 0.00 

 0.00 



8.08 

 0.03 



10, 14, 18 and 22 and were rolled 1, 2 and 4 B. & S. gage numbers 

 from commercial anneals in the 500 to 650° C. range. Figure 7 shows 

 Rockwell hardness plotted against tensile strength for alloy E brass. 



In a previous paper i" it was shown that different Rockwell hard- 

 ness values were required for material 0.040 in. and thicker, and mate- 

 rials less than 0.040 in. thick. This change in limits is dependent 

 upon thickness and is not sharply defined, but it has been found 

 sufficiently accurate for all practical purposes to consider that the 

 division occurs at 0.040 in. In the case of the alloy E brass rolling 

 series results shown by Fig. 7, only one curve was drawn since not 

 sufficient data were available to show this division. The curve prac- 

 tically agrees with the curves given in a previous paper '" for the 



1" H. N. Van Deusen, L. I. Shaw and C. H. Davis, he. cit. 

 50 



