

Process 



Material 

 Covered 



Chemical 

 Composition 



51 

 APPENDIX X 



SPECIFICATION FOR CAST IRON 



(In substantial agreement with A.S.T.M. Specification A 48-18 and A.R.E.A. 

 Bridge Material Specification, 1920) 



MANUFACTURE 



1. The castings shall be of tough grey iron and shall be made by the cupola process. 



2. This Specification covers three classes of grey iron castings, as follows: 



(a) Light Castings, those having any section less than 1/2 inch in thickness. 

 (6) Heavy Castings, those in which i o section is less than 2 inches in thickness. 

 (c) Medium Castings, those not included in either of the above two classes. 



CHEMICAL PROPERTIES AND TESTS 



3. Drillings taken from the fractured end of the transverse test bars shall conform 

 to the following requirements as to sulphur: 



Light castings not over 0.10 per cent. 



Medium castings " " 0.10 " " 



Heavy castings " " 0.12 " " 



4. One sulphur determination shall be made for each set of test bars cast. 



Transverse 

 Tests 



Number 

 of Tests 



Requirements 



Test Bars 



PHYSICAL PROPERTIES AND TESTS 



5. The transverse test bars shall be prepared as specified under "Test Bars" below, 

 and shall be placed horizontally upon supports 12 inches apart and tested under a cen- 

 trally applied load. The load on the test bar at rupture and the deflection at rupture 

 shall conform to the following minimum requirements: 



Load at centre, Ibs 



Deflection at centre, inch 



Class of Casting 



Light Medium Heavy 



2 500 2 900 3 300 



0.10 0.10 .010 



6. The rate of application of the load shall be such that a central deflection of 0.10 

 inch is produced from 20 to 40 seconds. 



7. Two sets of two test bars each shall be cast from each melt in thoroughly dried 

 green sand moulds (prepared as described below under "Test Bars") one set from the 

 first iron poured and the other set from the last iron poured. Where the melt exceeds 

 20 tons, an additional set of two bars shall be cast from each additional 20 tons or frac- 

 tion thereof. 



8. A transverse test of each bar cast shall be made. 



9. One test bar of each set (or pair of bars) cast shall conform to the requirements 

 specified above under "Transverse Tests" and under "Chemical Composition", other- 

 wise the castings represented by such bars shall be rejected. 



10. The form and dimensions of the mould for the test bars shall be in accordance 

 with Fig. I. The bottom of the bar shall be 1/16 inch smaller in diameter than the top, 

 to allow for draft and for the strain of pouring. The pattern shall not be rapped before 

 withdrawing. The flask shall be rammed up with green moulding sand, a little damper 

 than usual, well mixed and put through a No. 8 sieve, with a mixture of 1 to 12 bitumin- 

 ous facing. The mould shall be rammed evenly and fairly hard, thoroughly dried, and 

 not cast until it is cold. The test bar shall not be removed from the mould until cold 

 enough to be handled. It shall not be rumbled or otherwise treated, being simply 

 brushed off before testing. 



