APPENDIX A 

 TEST METHODS 



Tensile strength in accordance with American Society 

 for Testing Materials Specification E8-40T. 



Yield strength in accordance with American Society 

 for Testing Materials Specification E8-40T. 



Percentage of elongation in 2 inches in accordance with 

 American Society for Testing Materials Specification 

 E8-36. 



Percentage of reduction of area in accordance with 

 American Society for Testing Materials Specification 

 E8-36. 



Brinell hardness in accordance with American Society 

 for Testing Materials Specification ElO-27. 



Rockwell hardness in accordance with American 

 Society for Testing Materials Specifications E18-36 

 and E18-39T. 



Apparent elastic Umit.^ The value of the apparent 



1 WiLKiNS, R. A., Copper and Copper Base Alloy in the Con- 

 struction of Corrosion Resisting Equipment and Structures, Mech. 

 Eng., vol. 58, p. 809, 1936. 



elastic Umit as given in the text was determined by the 

 method illustrated in Fig. 1. Briefly, that method 

 consists in plotting from the stress-strain curve equal 

 increments of stress against corresponding increments of 

 strain. The strain corresponding to the point at which 

 the graph so obtained shows a marked change of slope 

 is considered the apparent elastic limit of the material. 

 The soundness of this method is indicated by Fig. 1, 

 in which are included load-unload curves. It wUl be 

 noted that specimens of the silicon bronze, stressed to 

 below, and up to, the value of the apparent elastic 

 limit, have no permanent set when the stress is released, 

 while specimens stressed in excess of that value have a 

 permanent set upon release of the stress. These tests 

 were made on a 100,000-pound capacity Southwark- 

 Emery hydraulic machine equipped with a Templin 

 automatic stress-strain recorder. The gage length 

 of the specimen used was 2 inches and strain was meas- 

 ured to an accuracy of 1 part in 100,000. 



n, h'n. = 0.002in. perin. 

 Fio. 1. 



333 



