144
Correspondence.
U.F.I.,
The Proceedings o f the Society f o r the P r o m o t i o n o f Engineering Education. Twelfth a n n u a l m e e t i n g , held in St. Louis, Mo., S e p t e m b e r I-3, 19o4. E d i t e d by C. F r a n k Allen, Fred. W . M c N a i r , Milo S. Ketchum, Committee. New Y o r k : E n g i n e e r i n g News Publishing Co. I9o5. Recent Advances i n the Metallurgy o f Iron a n d Steel. R. S. I-Iutton. R e p r i n t from the Journal of the S o c i e t y of Chemical Industry, I5 June, x9o5. N o t e s on Heat Insulation, particularl7 w i t h r e g a r d to m a t e r i a l s used in furnace construction. R.S. H u t t o n and T . R. Beard. R e p r i n t from the transactions of the F o u n d r y Society, August, 19o5.
Correspondence. H I G H - G R A D E S I L I C O N F O R P U R I F Y I N G CAST-IRON. "fo "rile EDITOR:--Since the publication of m y paper o n " R e c e n t P r o g r e s s in Metallurgy," in the D e c e m b e r issue of the Journal o f the Franklin Institute, I have received the enclosed interesting letter from Dr. Moldenke, which h e has kindly authorized me to send to you as a contribution to the discussion of the subject. As Dr. Mol d e n k e is a metallurgical c h e m i s t of international reputation, who has had wide experience, especially in cast-iron industries, his views a r e valuable and it is especially gratifying t o find t h a t he s t a t e s that the p r o c e s s alluded t o is "entirely new." His t h e o r y regarding the s e e m i n g p a r a d o x of obtaining "increase in strength, where the r e v e r s e would be expected when softening," agrees exa c t l y with my own views, as will a p p e a r from the following quotation t a k e n from the Journal of the Franklin Institute, M a r c h , 1888, in which I anI.ounced the result of experiments made in adding f e r r o m a n g a n e s e to car-wheel i r o n : " A r e m a r k a b l e effect is p r o d u c e d u p o n the c h a r a c t e r of h a r d iron by adding to the molten metal, a moment b e f o r e p o u r i n g it into a mould, a very small quantity of ferro-manganese, say one p o u n d of ferro-manganese in 6oo pounds of iron, and t h o r o u g h l y diffusing it t h r o u g h the m o l t e n mass by s t i r r i n g with a n iron rod. The result of s e v e r a l h u n d r e d carefully-cond u c t e d experiments which I have made, enables me to say that the t r a n s v e r s e s t r e n g t h of the metal is increased from thirty to forty per cent., the shrinkage is decreased from t w e n t y to thirty per cent. and the d e p t h of the chill is decreased about twenty-five p e r cent., while nearly one-half of the combined c a r b o n is c h a n g e d into free carbon; the p e r c e n t a g e of m a n g a nese in the iron is not sensibly increased by this dose, the small proportion of m a n g a n e s e which was added b e i n g f o u n d in the form of oxide in the scoria. The philosophical explanation of this extraordinary effect is, in my opinion, to be f o u n d in the fact t h a t the lotto-manganese acts simply as a deoxidizing agent, the m a n g a n e s e s e i z i n g any o x y g e n which has combined with the iron, forming manganic-oxide, which b e i n g l i g h t e r than the molten metal, rises to the surface and floats off with the scoria. W h e n a casting which h a s been artificially softened by this novel treatment is re-
Correspondence.
Feb., 19o6. ]
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melted, the effect of the ferro-manganese disappears and hard iron results as a consequence." The high-grade ferro-silicon (50 p e r cent. silicon) acts in a similar mann e r not only increasing strength but softening the metal. Small pulleys cast from iron treated in the way I described are now b e i n g t u r n e d at 4o feet per minute, whereas the usual s p e e d of t u r n i n g the same class of pulleys from the same grade of soft iron .untreated is 25 feet per minute. I stated in my p a p e r that as a result of a large number of tests I had f o u n d an average increase in s t r e n g t h of about 15 per cent. accompanied by m a r k e d increase in softness. I now have records s h o w i n g much larger gain in strength and resistance ( o v e r 25 per cent.) accompanied by remarkable increase in softness. T h e s e tests were cast from iron containing 15 per cent. of s t e e l in the mixture. Very truly,
A. E. OUTERBRIDGE, JR. PHILADELPHIA, PA., Dec. 23d, I9O5.
AMERICAN
FOUNDRYMEN'S
President, T h o s , D. West. T h o s . D. West F o u n d r y Co.,
ASSOCIATION,
Secretary-Treasurer R i c h a r d Moldenke. Natchung, N. J. Sharpsville, Pa.
Office of the Secretary,
WATCHUNG, N. J., Dec. ITth, I9O5. MY DEAR MR. OUTERBRIDGE:-T h a n k you very much for your v a l u e d article. I have read it with great interest. The portion a n e n t the addition of high-grade silicon is especially valuable and entirely new. Y o u will no doubt find that the increase in strength, where the r e v e r s e would be expected when softening, is due to the purifying effect of the silicon addition when not made in the cupola. This is similar to that p r o d u c e d by ferro-manganese when added to the car-wheel mixtures. I hold that t h e s e alloys when they are effective at all, do take out dissolved o x y g e n or perhaps o t h e r gases, bringing out silicon o r manganese as the case may be, and p a s s i n g into the slag. The result is a cleaning u p ' a n d b e t t e r adherence of the crystals, r a i s i n g the resilience and general strength. I think you will find further that where steel additions have been made, you will get still b e t t e r results, as the melting p o i n t b e i n g raised, t h e s e alloys get in t h e i r work better. Your p a p e r shows that we have not yet exhausted our resources in the foundry. May you discover many new ways and means yet. Sincerely yours,
(Signed) VOL. C L X I .
No. 962
RICHARD
MOLDENKE. IO