MATERIALS AND WORKMANSHIP 



47 



190. Cast Iron. Except where chilled iron is specified, cast- 

 ings shall be made of tough gray iron, with sulphur not over 

 0.10 per cent. They shall be true to pattern, out of wind and 

 free from flaws and excessive shrinkage. If tests be demanded 

 they shall be made on the " Arbitration Bar " of the American 

 Society for Testing Materials, which is a round bar 1 in. in diam- 

 eter and 15 inches long. The transverse test shall be made on a 

 supported length of 12 in. with a load at middle. The minimum 

 breaking load so applied shall be 2900 Ibs. with a deflection of 

 at least -^ in. before rupture. 



191. Wrought-Iron Bars. Wrought iron shall be double 

 rolled, tough, fibrous, and uniform in character. It shall be 

 thoroughly welded in rolling and be free from surface defects. 

 When tested in specimens of the form of Fig. 3, or in full-sized 

 pieces of the same length, it shall show an ultimate strength of 

 at least 50,000 Ibs. per sq.in., an elongation of at least 18 per 

 cent in 8 inches, with fracture wholly fibrous. Specimens shall 

 bend cold, with the fiber, through 135 degrees, without sign of 

 fracture, around a pin the diameter of which is not over twice 

 the thickness of the piece tested. When nicked and bent, the 

 fracture shall show at least 90 per cent fibrous. 



MATERIALS FOR CONCRETE REINFORCEMENT BARS* 



192. Process of Manufacture. Steel may be made by either 

 the open-hearth or Bessemer process. Bars shall be rolled from 

 billets. 



* As adopted by The Association of American Steel Manufacturers, 1910. 



