Metallurgists to Utilize Nucleonic Methods A STAFF REPORT A. FI'LL week's program of technical papers and a n exposition attracting a registration said t o approximate 30,000 provided a very impressive National Metal Congress in Chicago, Oct. 18 t o 24. This meeting was sponsored by the American Society for Metals, the American Institute of Mining and Metallurgical Engineers, the American Welding Society, and the American Industrial Radium and X - R a y Society. One of the features of the meeting was a talk on "Developments in the Use of the Nuclear Chain Reactor" by Walter Zinn, director of the Argonne National Laboratory. I>r. Zinn spoke on points which would be of interest to metallurgists and would yield information required for the design and operation of chain reactors either for power or other purposes. Dr. Zinn stressed the measurement of parasitic neutron capture in pile structural materials, explaining that any chain reacting system represents a critical balance between production of neutrons, absorption of neutrons, and leakage of neutrons t o the outside. In any operation with a pile, he emphasized, the strictest attention must be given to this point; otherwise the reactor will fail to work at all. Another point discussed was the fact that only certain isotopes of an element absorb neutrons. Mercury was cited as a specific example, its isotopes 196 and 199 being the only ones having a large absorption. Of particular importance to the metallurgist, stated Dr. Zinn, is the manufacture of radioactive isotopes and their use as tracers. Tens of grams of radium equivalent can be formed easily by even a small research pile and many of the isotopes may be useful to metallurgists. As an example, he cited corrosion research, wherein radioactive iron could be plated on a surface so that not only can the loss of metal be determined with great sensitivity but it may be traced when deposited elsewhere. Polarized neutrons were also discussed by Dr. Zinn, who said that neutrons could be directionally polarized b}r passing them through a piece of magnetized iron. Metals
of Nucleonic
Importance
Uranium and other nietate of nucleonic importance were discussed from a metallurgical standpoint b y John Chipman, Massachusetts Institute of Technology. He described uranium as hard, heavy, and ductile, having great tensile strength when properly worked. I t is susceptible t o corrosion and no case has been found where uranium could be added usefully
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t o another metal. It is formable by rolling and is extrudible. Thorium was described a s lighter, more ductile, and much more corrosion resistant. This element, said Dr. Chipman, is more plentiful in nature than is uranium. It is not much used in atomic energy work at present but promises to be. Its high melting point, in the range of 1,800° C , makes working difficult because of its ease of formation of oxides and carbides. Beryllium is another element which is useful in atomic development. It is corrosion-resistant and light. This metal, said Dr. Chipman, does not capture neutrons t h e way some do and it has an important activity as a moderator t o slow down high speed neutrons. It would be many times as efficient as carbon for use in a pile and much less, would be required. I t is not pleasant t o work with metallurgically because it does too many things not desired. The salts are stable, he reported, saying that he knew of no metal which would take oxygen away from the oxide. However, it can be extruded or rolled with a slight improvement in properties. The physical metallurgy of plutonium, said Dr. Chipman, is not divulged beyond Los Alamos. Effect of Factors on
Metallurgical Steel
S. A. Herres and C. H. Lorig, in discussing the influence of metallurgical factors on the mechanical properties of steel reported that data were obtained which indicate that, in· the absence of grain boundary precipitates, or envelopes, toughness is not markedly affected b y a large increase in austenitic grain size. I t was found that t h e addition of nitridestabilizing elements did not affect the susceptibility to temper brittleness of several steels. The effects of homogenization heat treatments on the hardenability, the impact properties and the time-temperaturetransformation curves for,certain selected cast steels were studied by R. J. Marcotte and C. T. Eddy, Michigan College of Mining and Technology. The investigation revealed that for the steels studies and for t h e tftnc and temperatures of homogenization employed, the effects on the mechanical properties, attributable solely t o homogenization, are negligible. Jay R. Burns, Air Matériel Command, Wright Field, reported that beryllium additions of 0.001% or greater to magnesium alloys produce a marked reduction in the tendency of the magnesium alloys to burn. Alloys containing beryllium may be held molten without fluxes
CHEMICAL
and successfully cast in foundry sand containing no inhibitors. In a study of the effect of carbon content on the hardenability of boron steels; by G. D . Raher and C. D. Armstrong, Carnegie-Illinois Steel Corp., results indicated that, with boron additions of 0.0006· to 0.0045%, only carbon content a n d intensity of deoxidation affect the hardenability factor for boron to a demonstrable degree. A paper by X. A. Ziegler, W. L. Meinhart, and J. R. Goldsmith, Crane Co., stated that increasing the silicon content of carbon and carbon-molybdenum steel' from 0.3 t o 2 % produces (a) moderate increase of tensile strength, yield point, and hardness, (b) moderate decrease o f elongation and reduction of area, and (c) a considerable reduction of impact resistance, which becomes more pronounced as the silicon content increases·· above 1%. Jet Engine
Alloy
An alloy that remains "extremely high" at high temperatures and manufacturable by casting was reported by N . J. Grant, M I T , as developed to meet the problemsof jet engines and rockets. He stated that the alloy was a cobalt-chromium type with a high strength at temperatures· ranging from 1,350° t o 1,800° C , or well within the temperature ranges of jet engines. One of the new developments exhibited: at the metal exposition was a machine that surface hardens metal parts in production quantities by employing flame in the heat treatment, its revolutionary feature being temperature control within 5° C. of that desired. The machine is produced by the Cincinnati Milling Machine Co. Another device is a "reflectogage" made b y Sperry Products, Inc. T h i s was developed by the General Motors Research Corp. and employs sound t o determine the thickness of metals and other solids. Awards The Henry Marion Howe Medal was presented to W. A. Pennington by the ASM for the paper of highest merit published in its Transactions during 1946. Other awards included the Albert Sauveur Achievement Award to F. P. Zimmerli, the ASM Gold Medal to C. H. Mathewson, the ASM Medal for the Advancement of Research to Charles R. Hook, and the Past Presidents Medal to Charles H. Hcrty, Jr.
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ENGINEERING
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