SHEET NON-FERROUS METALS 



765 



this machine built for experimental purposes. A strip of metal S, 

 § in. wide, is clamped between a pair of radius blocks, B, selected at 

 random. The upper portion of the specimen is held by a tensioning 

 grip, T, and guided by two clamps, C. The specimen is bent back 

 and forth over the pair of radius blocks and each bend of 90 deg. 



50 



t'' 



130 



20 



10 

 40,00(5 50,000 



60,000 70,000 80,000 90,000 

 TENSILE STRENGTH - PSI 



100,000 110,000 



Fig. 5 — -Relation of Number of 90-deg. Bends to Failure to Tensile Strength of 

 Alloy G Brass. Ratio of Mandrel Radius to Thickness, 8 to 1. 



and return is recorded as one bend by a counter. Using another 

 strip of the same metal but a pair of radius blocks of different radii 

 another result is obtained. If the number of bends is plotted 

 on log paper against the ratio of the thickness of the metal to the 

 radius of the blocks, a straight line results. It is possible therefore 

 to select any standard ratio of block radius to thickness of metal and 



