THE USE OF IRON. 6? 



" MEDIUM STEEL (TANK). 



Tensile strength 60,000 to 68,000 Ibs. per sq. in. 



Elastic limit, one-half the ultimate strength. 



Elongation 20 to 23^ 



Reduction of area 40 " 45^ 



Chemical requirements for phosphorus and sulphur same as for 

 "soft steel." 



" SOFT STEEL (SHELL). 



Tensile strength . . . 54,000 to 62,000 Ibs. per sq. in- 

 Elastic limit, one-half the ultimate strength. 



Elongation 25^ 



Reduction of area 50$ 



If acid open-hearth steel : phosphorus under 085^ 



" " sulphur under 065^ 



If basic open-heath steel : phosphorus under 035^ 



" sulphur under .04$ 



" FLANGE STEEL. 



Ultimate tensile strength 54,000 to 62,000 Ibs. per sq. in. 



Elastic limit, net less than 33,ooo Ibs. 



Elongation. . 2J% 



Reduction of area 50^ 



If acid open-hearth steel : 



Phosphorus not more than 065^ 



Sulphur not more than 05$ 



Jf basic open-hearth steel : 



Phosphorus not more than 035^ 



Sulphur not more than -35# 



" FIRE-BOX STEEL. 



"To be made of acid open-hearth steel of the following strength : 



Ultimate tensile strength 56,000 to 64,000 Ibs. per sq. in. 



Elastic limit 33,000 Ibs. 



Elongation 28^ 



Reduction otf a?rea v . , . . 56^ 



Phosphorus 035$ 



Sulphur , , 035^ 



