

Number 

 of Tests 



Retests 



Character 

 of Fracture 



Defects 



Permissible 

 Variations 



41 



18. Test specimens for bars over \% inches in thickness or diameter may be mach- 

 ined to a thickness or diameter of at least 3/4 inch for a length of at least 9 inches; or 

 tension test specimens may conform to the dimensions shown in Fig. 2, in which case, 

 the ends shall be of a form to fit the holders of the testing machine in such a way that 

 the load shall be axial. Bend test specimens may be 1 x 1/2 inch in section. 



19. Tension test specimens for pins and rollers shall conform to the dime 

 shown in Fig. 2. In this case the ends shall be of a form to fit the holders of the testing 

 machine in such a way that the load shall be axial. Bend test specimens shall be 1 x 

 1/2 inch in section. 



20. The tension test specimens shown in Fig. 2 and the 1 x 1/2 inch bend test speci- 

 mens for pins and rollers shall be taken so that the axis is 1 inch from the surface; and 

 for other bars over \}/2 inches in thickness or diameter, midway between the centre and 

 surface. 



21. The machined sides of rectangular bend test specimens may have the corners 

 rounded to a radius not over 1/16 inch. 



22. Test specimens for rivet bars which have been cold drawn shall be normalized 

 before testing. 



Radius not less than 



*-2" Gouge length.-* 



Fig. 2 



Note The gauge-length, parallel portions and fillets shall be as shown; but the 

 ends may be of any form which will fit the holders of the testing machine. 



23. One tension and one bend test shall be made from each melt; except that if 

 material from one melt differs 3/8 inch or more in thickness, one tension and one bend 

 test shall be made from both the thickest and the thinnest material rolled. 



24. If any test specimen shows defective machining or develops flaws, it may be 

 discarded and another specimen substituted. 



25. If the percentage of elongation of any tension test specimen is less than that 

 specified under "Tension Tests" and any part of the fracture is more than 3/4 inch from 

 the centre of the gauge length of a 2 inch specimen or is outside the middle third of the 

 gauge length of an 8 inch specimen, as indicated by scribe-scratches marked on the 

 specimen before testing, a retest shall be allowed. 



26. Test specimens of structural or rivet steel shall show a fracture of uniform, 

 silky appearance; of bluish grey or dove colour; and entirely free from granular, black 

 and brilliant specks. 



FINISH 



27. Finished rolled material shall be free from cracks, flaws, injurious seams, blisters, 

 ragged and imperfect edges, and other surface defects. It shall have a smooth finish, 

 and shall be straightened in the mill before shipment. 



PERMISSIBLE VARIATIONS IN WEIGHT AND THICKNESS 



28. The cross-section or weight of each piece of steel shall not vary more than 2.5 

 per cent, from that specified ; except in the case of sheared plates, which shall be covered 

 by the following permissible variations. One cubic inch of rolled steel is assumed to 

 weigh 0.2833 Ib. 



