Abstract
Various observers does not agree exactly as to the effect of phosphorus on the physical properties of steel; owing to the fact that its effect changes by the amount of carbon, manganese and other impurities in steel. The present investigation was carried out for finding the effect of phosphorus upon the mechanical properties of our basic open-hearth steel as rolled by means of eliminating the effect of carbon and manganese on the physical properties of steel. The results of it may be summalized as follows.
(1) On the plain carbon steel which contains carbon, manganese and phosphorus in simultaneously, the effect of phosphorus, under the same amount of carbon, was detected by means of eliminating the effect of manganese present.
(2) The effect of phosphorus on the tensile strength, yielding point and elongation of steel increases with the increase of the carbon content and the impact resilience, under the same amount of carbon and of manganese, decreases with the increase of the phosphorus content.
(3) So far as the relations between chemical compositions and physical properties of steel are concerned, the presence of about 0·08 phosphorus for plain carbon steel does not to be damaged in practice the mechanical properties of steel.
(4) The relations between chemical compositions and mechanical properties of our basic openhearth steel as rolled may be expressed by the following empirical formula
T=0·33C+0·008CP+0·64P+0·006CMn+0·02Mn+30·2
Y=0·15C+0·00087CP+0·37P+0·0009CMn+0·11Mn+18·0
E=312/C-(0·0022CMn+0·011CP+0·127P)+22·0
where; T=Tensile strength in kg/mm2 Y=Yielding point in kg/mm2 E=Elongation in % G.L. 50mm dia of spicimen 14mm C=Carbon content in %×100 Mn=Manganese content in %×100 P=Phosphorus content in %×100
