TRANSACTIONS OF SECTION J. 



449 



Table No. VII. 



(Roads and Bridges Dcpartjncnt, N.S.W.) 



Strength of Wrought Iron under Varying Stresses. 



[Calculated from Weyrauch's Formula for Breakiug-strength of 21 tons.] 



When ' = 1-0, ultimate strength = 20'1 tons per square inch. 



max. 



Note.- 

 8/4/90. 



Table No. VIII. 



Opposite Stresses. One Stress Zero. 



Material. 



Least. Greatest. 



Least. Greatest. 



Similar Stresses. 



Least. Greatest. 



Eange Zero. 

 Ultimate 

 Statical 

 Strength. 



Bauschinger's Endubance-Tests. 

 stresses requiring 5 to 10 million repetitions to cause fracture. Tons per square inch. 

 Wrought- - 7-15 + 7-15 13-10 11-4 19-2 | 22-8 



iron plate 

 Bar iron . . - 7-85 + 7-85 14-4 18-3 22-02 26-6 



Bar iron .. - 86.5 + 8-65 15-75 13-2 21-92 26-4 



Bessemer - 8-55 + 8-55 15-70 14-3 23-8 28-6 



mild-steel 

 plate 

 Steel axle.. -105 +10-5 19-7 200 321 40-0 



Steel rail . . - 9-7 -f 9-7 184 19-5 30-85 39-0 



Mild-steel - 865 + 8-65 6 15-8 13-3 22-55 266 



boiler-plate ' 



Limits op Stress from Wohler's Endurance-Test. 

 Stresses in tons per square inch for which fracture occurs only after an indefinitely 

 large number of rei^etitions. 



Wrought- 



iron plate 



Krupp's axle 



steel 

 Untempered 

 spring steel 



29 



22 8 



520 



57-5 



