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IV. — Methods for Detecting the more Highly Phosphorised Portions 



in Iron and Steel. 



By J. E. Stead, F.E.S. 



CEead March 15th, 1905.) 

 Plates V. and VI. 



On reading the published researches of micro-metallographers 

 it would appear that very little attention has been paid to the 

 methods for detecting or identifying the more highly phos- 

 phorised portions in iron and steel. I have, however, repeatedly 

 had occasion to report upon the structure of steels and to draw 

 attention to irregular distribution of phosphorus. 



Signor E. Schanzer, C.E., in a paper read before the Institute 

 of Naval Architects, April 6th, 1900, referred to the peculiar bands 

 of ferrite and pearlite parallel to the axis of a propeller shaft, which 

 he had examined (pi. V. fig. 1.). Every micro-metallographer must 

 have noticed a similar structure. 



Professor Arnold and Mr. S. A. Houghton have described them 

 in papers they have published. 



Signor Schanzer, when discussing the causes leading to this 

 peculiar arrangement, stated that " nothing can be said as to 

 whether the high amounts of phosphorus are favourable to the 

 development of the particular structure, nor can any other cause 

 be suggested." 



That phosphorus is at least responsible in many cases for the 

 arrangement of ferrite and pearlite in trains, lines or bands, I have 

 most conclusively demonstrated, and it appears most probable that 

 Signor Schanzer's inference is correct for the case examined. 



Mr. Henry Fay in an article published in " The Metallographist " 

 1901, page 115, describes a segregation of phosphorus in a piece 

 of cold rolled shafting, in winch, after Osmond's polish-attack, 

 midway between the centre and exterior there appeared a white 

 ring on a dark ground. The ring contained 0*214 p.c. phosphorus 

 and the dark portions 0*09 p.c. 



Mr. Fay believed the white ring contained some of the phos- 

 phide eutectic, but this seems scarcely likely, for it is not until 

 such low carbon steel contains above 1 p.c. phosphorus that the 

 eutectic containing 10*2 p.c. phosphorus separates. Probably the 

 structure observed consisted of alternate portions of steel contain- 

 ing high and low amounts of phosphorus, a condition which might 

 easily lead to the supposition, judging from the appearance alone, 



