Manchester Memoirs, Vol. xlvi. (1902), No. 1. 



VII. On the Failure of certain Cast Steel Dies used 

 in the Manufacture of Drawn Tubes. 



By George Wilson, D.Sc, 



Demonstrator in the Whitworth Engineering Laboratory, Owens College, 

 Manchester. 



Received and read famiary "Jth, 1 902. 



In the manufacture of drawn copper tubes, it is usual 

 to draw the tube through a somewhat tapering hole 

 formed for this purpose in the centre of a cast steel die. 

 By this means the tube is increased in length, diminished 

 in area, and improved in quality. During this process, 

 the dies may be placed under severe stress, and, as the 

 nature of the material of which they consist allows no 

 preliminary warning of failure, those who are using them 

 may be in positions of some danger. 



The receipt of particulars of six such failures seems 

 sufficient reason for enquiring into the nature of the 

 stresses to which such dies may be subjected during use. 

 Such an enquiry, moreover, raises further points of interest 

 concerning the plastic strain in the material forming 

 the tube. With regard to the stresses in the die it is evident 

 that there may be initial stresses set up during its manu- 

 facture ; on these will be superposed the statical stresses 

 due to the drawing of the tube, and, further, there may be 

 dynamical stresses caused by vibrations in the die. Any 

 die designed to resist the statical stresses should have a 

 large factor of safety to cover any initial and vibratory 

 stresses which may occur, otherwise, on two or three 

 occurring simultaneously, fracture may result. 



February loth, igo2. 



