TRANSACTIONS OF SECTION B. 295 



The steel is now broken up into small pieces and melted in crucibles, and cast 

 into ingots. These are sent to the forge, -where they are heated and rolled. In 

 this part of the process the chief difficulty with which the silter has to contend is 

 the porous or ' honey-combed ' structure of the steel. 



One of the characteristic features relied on by practical men as indicating the 

 quality of a piece of steel is the appearance of its fracture ; but this is by no means 

 an infallible test, as the fineness or coarseness of grain can be produced by 

 mechanical treatment or chemical means. 



The characteristic property possessed by steel is its capability of being hardened 

 and tempered. The temper of cast steel may be said to range from 075 to T50 

 per cent, carbon. The temper of steel is an important question in connection with 

 the purpose for which it is required, thus a steel containing 1-50 per cent, of carbon 

 is the class employed for razors. l - 25 per cent, is that known as ' tool temper.' 

 Steel containing TOO per cent, carbon is termed 'chisel steel,' and this temper is 

 extensively used in the arts. 



The favourite marks of Swedish now employed in the manufacture of this kind 

 of steel, are those obtained from Dannemora, the most noted of which are the 00 = 



Double Bullet, Q, = GL, and (l) = Hoop L. 



The most important of the elements which affect the quality and mechanical 

 properties of steel are the following : 



Carbon, Silicon, Sulphur, Phosphorus, and Manganese. 



Carbon, by its direct combination with iron, is essentially the steel-forming ele- 

 ment, and greatly increases the hardness and tensile strength of the metal. The 

 maximum quantity of carbon capable of being taken up by iron is 6 - 5 per cent, to 

 7 - 00 per cent. This high percentage of carbon is only attained, as in the case of 

 rich Ferromanganese, containing as much as from 85 to 86 per cent, of mangauese. 



Silicon. — The action of this element on steel is to produce both red and cold 

 shortness, especially in high made steels. Under certain conditions, it is capable 

 of imparting hardness without brittleness. The presence of this element also tends 

 to favour a solid casting, and prevent the formation of a honey-combed structure. 



Sulphur in steel, as is well known, produces ' red shortness,' and has also a ten- 

 dency to prevent the chemical combination of iron with carbon, and also to dis- 

 place it when in combination. 



Phosphorus produces cold shortness and brittleness, but the detrimental influence 

 of this element, when present only in small quantities, can be partially neutralised, 

 providing the percentage of carbon is very low. 



Manganese is a valuable ally of the steel melter, and serves to correct the evil 

 effects produced by the presence of sulphur, oxygen, &c. ; and when in the state of 

 an oxide serves to eliminate a large percentage of the silicon. 



Mangauese is generally introduced into the steel in the form of ' Spiegeleisen,' an 

 alloy of iron, carbon, and manganese, generally containing about 10 per cent, of the 

 latter element. 



Other metals have been employed to replace carbon, such as tungsten, chromium, 

 and titanium : these impart great hardness and fineness to the texture of steel. 



For a considerable amount of practical information given in his paper, but 

 necessarily omitted from this abstract, the writer is indebted to a valuable essay 

 written some years ago on this subject by Henry Seebohm, Esq., of the firm of 

 Messrs. Seebohm & Dieckstahl. — This paper is not intended to give any additional 

 information to the practical steel makers of Sheffield, as to the manufacture of 

 steel, or to offer any criticisms or advice in the matter; its object is simply to give 

 an outline of the manufacture as it is still carried on in tbis town, with tbe hope 

 that it may prove interesting to many of those who have come from a distance to 

 attend the visit of the British Association, and who are unacquainted with the pro- 

 cess which has caused Sheffield to become the great manufacturing steel centre in 

 this country. 



