A NEW CAST IRON.

Progress, Volume II, Issue 2, 1 December 1906, Page 55

A NEW CAST IRON.

It is reported in the Times Engineering Supplement that a member of the well-known firm of William Sellers & Co., of Philadelphia, sent recently to the Journal of the Franklin Institute an account of some experiments made by him concerning the effect of adding a small percentage of high-grade ferro-silicon to molten cast iron after tapping from the cupola into the ladle. The results were so encouraging as to lead to an extension of the experiments, and the facts as determined by a large number of these are reported in the Iron Age. In test bars of foundry iron treated in the ladle with small quantities of ferro-silicon containing 50 per cent, silicon there was found an average gain of about 15 per cent, in strength, accompanied by a somewhat larger average gam in ductility or bending quality, accompanied by a marked increase in softness. " The silicon in untreated samples ranged from 1.7 to 2.25 per cent., and m the treated specimens from 2 to 2.75 per cent. The addition of even so little as 1 lb. of the alloy m powdered form m a ladle containing 200 lbs. of foundry iron produced a remarkable effect not only as a softener, but invariably increased the strength and resilience of the metal, this occurring with an addition of a little less than 0.25 per cent, of silicon to the iron. By adding four times this amount of the alloy to a very hard iron mixture in a ladle, which ran quite white when cast in thin section, and was therefore entirely unsuitable for small castings requiring to

be machined, it was found that a soft grey metal of good strength and ductility was produced, having a low shrinkage and being suitable for casting pulleys and other light work." It is expected that on a lowering of the present price of the powdered alloy, which is shortly anticipated, the method will become of value in general foundry work.

New buildings erected in Wellington during 1905-6 numbered 814, valued at against 614, valued at during the preceding year.