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THE IEKIGATION AGE. 



THE BATTLE AGAINST IRON CORROSION 



By J. T. HAY 



Metallurgist and Chemist 



THE progress in the art of manufacturing iron 

 and steel has been most remarkable in the last 

 few years and of all the factors which have con- 

 tributed towards it none has been more influential 

 than the destructive forces of corrosion, which have 

 challenged the best efforts of man to produce a 

 permanent iron or steel product. It is a well- 

 established fact that the processes of manufacture 

 have much more to do with the final lasting quality 

 of the material than was formerly supposed. 



It is a recognized fact that the open-hearth 

 furnace alone is suitable for the production of high- 

 grade metal in large quantities. The electric fur- 

 naces are rapidly forging their way to the front, 

 but they have not been long enough in the field 

 for us to accurately determine their position. 

 Therefore, we will deal with the open-hearth fur- 

 nace and its production, and try to show some of 

 the many factors in the process of manufacturing 

 which have an influence on the corrosion of the 

 finished products. To begin with, it is necessary 

 that we have raw materials of good quality, pig 

 iron, scrap and fluxes ; the standard specifications 

 of basic pig are suited for our requirements. Great 

 care must be taken in the purchasing of scrap, as 

 it requires but a small amount of impurities in the 

 scrap to cause unlimited trouble in the finished 

 product. Cast iron scrap of all kinds is to be 

 avoided. Furnace operations are the next factor 

 to be considered. The education of the men operat- 

 ing the open-hearth furnaces is of the utmost im- 

 portance. 



The proper regulation of the temperature of 

 the furnace is a most important factor, influencing 

 the quality of the product, and the ascertaining of 

 the temperature with the eye, as it is customarily 

 done, is an uncertain proposition at the best. After 

 the metal has become thoroughly molten and the 

 temperature has been carefully watched, a sample 

 is then taken from the bath and carefully analyzed 

 before the material is removed from the furnace. 

 The old method of determining the amount of phos- 

 phorus and carbon in the metal by the visual appear- 

 ance of a fractured test piece is being rapidly super- 

 seded by making preliminary chemical analyses 

 before the material is tapped. Too much stress can 

 not be laid upon this point, if quality in the material 

 is aimed at. But even when these precautions are 

 taken, many a heat is ruined by carelessness in 

 tapping and handling the metal when in the ladle. 

 The melter must have before him the conditions to 

 which the metal was subjected during the three or 

 four hours previous to the tapping, together with 

 the preliminary analyses, to determine the neces- 

 sary treatment in the ladle, as this is his last chance 

 to add to or detract from the quality of the metal. 



Many defects in steel can be traced to dirty 

 molds or lack of care in pouring the molten metal 

 therein. 



When the ingot has been removed from the 



mold it is usually placed in a reheating furnace or 

 soaking pit before the ingot is cold. The heat of 

 these pits should always be controlled by a pyro- 

 meter, because the temperature must be regulated 

 according to the chemical analysis of the metal. 



Let us outline now, but briefly, the theory and 

 effects of corrosion. Corrosion, or the rapid rust- 

 ing of iron and steel, may be considered as an effect 

 of the combined action of water and oxygen, or, in 

 a broad sense, of moisture and air. The most wide- 

 ly accepted theory of the cause of this rapid rusting, 

 or corrosion, called the electrolytic, is based on 

 the fact that when two substances, having different 

 electrical potentials, are immersed in a suitable 

 electrolyte, an electric current is set up and corro- 

 sion begins at once. In iron or steel the various 

 impurities differ from the element iron in their 

 electrical potentiality, and the moisture in the air 

 contributes the electrolyte. It is also true that this 

 action is of a chemical nature and that because of 

 the very close connection between electrical and 

 chemical action we are able to control this chemical 

 action by stopping or accelerating the electrical 

 action. The purity of iron has a marked influence 

 on the rapidity of corrosion. The quantity of the 

 impurities must not only be very minute, but those 

 few elements which it is impossible to remove en- 

 tirely must be absolutely homogeneously distributed. 

 Because of the extreme sensitivity of iron, great 

 care must be used at its physical treatment, or the 

 work of having eliminated the impurities will be 

 labor lost. The strains produced by excessive speed 

 in rolling, unless removed by careful annealing, will 

 generate active corrosion. 



Some manufacturers have tried to offset their 

 neglect to remove the objectionable impurities and 

 their lack of careful physical treatment by the addi- 

 tion of copper. This doped steel, instead of being 

 benefited thereby, has to undergo an increase of 

 the total of its impurities, and thus the segregation 

 of the latter is rendered easier, which two factors 

 accelerate corrosion rather than retard it. 



ASKS CAREY ACT REVISION 



Congressman Carl Hayden, of Arizona, has 

 introduced a bill (H. R. 15218) to revise and amend 

 the Carey act. The original act was passed in 1894 

 and has been amended in a number of particulars 

 since that time. The Hayden bill provides for a 

 more strict supervision, both on behalf of the State 

 and the United States with respect to the feasibility 

 of proposed irrigation projects, thus protecting 

 both the investor and the settler. The bill reduces 

 the area that may be acquired by any one person 

 from 160 to 80 acres, and requires actual residence 

 on the land for two years and the cultivation of 

 one-half of the irrigable area of the entry before 

 patent can issue. The settler is protected by a pro- 

 vision which prohibits the sale or entry of land 

 until water is available for its irrigation, and the 

 time of payment is extended from ten to fifteen 

 vears. 



