39 



APPENDIX VII 



Process 



Chemical 

 Composition 



Ladle 

 Analyses 



Check 

 Analyses 



Tension 

 Tests 



SPECIFICATION FOR STRUCTURAL STEEL FOR BRIDGES 



(In substantial agreement with A.S.T.M. Specification A7-21) 



MANUFACTURE 



1. The steel shall be made by the open-hearth process. 



CHEMICAL PROPERTIES AND TESTS 



2. The steel shall conform to the following requirements as to chemical composition: 



Structural Steel Rivet Steel 



Phosphorus /Acid not over 0.06 not over 0.04 per cent. 



\Basic " " 0.04 " " 0.04 " " 



Sulphur ' 0.05 0.045 



3. An analysis of each melt of steel shall be made by the Manufacturer to determine 

 the percentages of carbon, manganese, phosphorus and sulphur. This analysis shall be 

 made from a test ingot taken during the pouring of the melt. The chemical composition 

 thus determined shall be reported to the Engineer and shall conform to the requirements 

 specified above. 



4. Analyses may be made by the Engineer from finished material representing each 

 melt. The phosphorus and sulphur content thus determined shall not exceed that 

 specified above by more than 25 per cent. 



PHYSICAL PROPERTIES AND TESTS 



5. The material shall conform to the following requirements as to tensile properties, 

 except as modified hereinafter: 



Specimen 

 Tension Tests 

 of Eyebar 

 Material 



Yield Point 



Modifications 

 in Elongation 



6. In order to meet the required minimum tensile strength of full-sized annealed 

 eyebars, the Engineer may determine the tensile strength to be obtained in specimen 

 tests; the range shall not exceed 14000 Ibs. per sq. inch, and the maximum shall not 

 exceed 74 000 Ibs. per sq. inch. The material shall conform to the requirements as to 

 physical properties (other than tensile strength) specified under "Tension Tests" above, 

 and under "Modifications in Elongation" and "Bend Tests" below. 



7. The yield point shall be determined by the drop of the beam of the testing mach- 

 ine. 



8. For structural steel over 3/4 inch in thickness, a deduction of 0.25 from the 

 percentage of elongation in 8 inches specified above shall be made for each increase of 

 1/32 inch in thickness above 3/4 inch to a minimum of 18 per cent. 



9. For structural steel under 5/16 inch in thickness, a deduction of 1.25 from the 

 percentage of elongation in 8 inches specified above shall be made for each decrease of 

 1/32 inch in thickness below 5/16*inch. 



