1890.J Sir Frederick Bramwell on Welding hy Electricity. 18^ 



WEEKLY EVENING MEETING, 



Friday, April 18, 1890. 



Sir Frederick Abel, C.B. D.C.L. F.E.S. Vice-President, in the Chair. 



Sir Frederick Bramwell, Bart. D.C.L. M. Inst. C.E. F.R.S. 

 Eon. Sec. and V.P.B.L 



Welding hy Electricity. 



There are certain technical words which relate to operations of a 

 character so decisive, that the words have been adopted into ordinary 

 language, such words as "grafting," " safety valve," "stereotyping," 

 "welding." I dare say that every one who speaks of "grafting," 

 or of a " safety valve," knows something of the operation or of the 

 function of the apparatus of which he is speaking ; perhaps he is 

 not quite so clear about " stereotyping." But when it comes to 

 " welding," I doubt whether many persons know what the term really 

 means, as we engineers understand it, or could tell how many and 

 what metals are capable of being united by welding ; and I also doubt 

 whether there are many who could distinguish between " fusing and 

 burning together " and true " welding." 



I do not myself know how to give a definition of " welding " 

 as it is understood by practical men ; but Dr. Percy did know, and 

 if you will pardon me I will read a few lines from his book, 

 which state more clearly than I could hope to do in words of 

 my own, the meaning of welding, as ordinarily practised. He 

 says :* — " Iron has one remarkable and very important property, 

 namely, that of continuing soft and more or less pasty through a 

 considerable range of temperature below its melting-point. It is 

 sufficiently soft at a bright red-heat to admit of being forged with 

 facility, as every one knows ; and, at about a white-heat, it is so pasty 

 that when two pieces at this temperature are pressed together they 

 unite intimately and firmly. This^ is what occurs in the common 

 process of welding. Generally metals seem to pass quickly from the 

 solid to the liquid state, and so far from being pasty and cohesive at 

 the temperature of incipient fusion, they are extremely brittle, and 

 in some cases easily pulverisable. But, admitting that there is a 

 particular temperature at which a metal becomes pasty, its range is 

 so limited in the case of the common metals, that it would scarcely be 

 possible to hit upon it with any certainty in practice ; or, if it were 

 possible, its duration would be too short for the performance of the 



Percy's 'Metallurgy,' Iron and Steel, 1864, pp. 5 and 6 



