1939: Metallurgy

In 1938 an inquiry was addressed to two thousand research men in the United States, Canada, England, France and Germany, asking what would be the outstanding contribution to research in their particular field within the next three years. In the field of metals the responses were: cheaper chromium steels for railroad rolling stock; sheet metal with adherent colored surface for store fronts, autos, house trims and toys; direct casting of copper, aluminum and alloys; production of manganese from domestic deposits; synthetic mica; electroplating color on metals. These replies would scarcely seem to indicate that any metallurgists anticipated an outbreak of war, nor were they especially concerned with metallurgical problems directly related to war. From this we are inclined to conclude that scientific research is a gradual process, the direction of which is not deflected by international emergencies but only quickened by those emergencies.

Trends in Metallurgical Research.

While the leading countries of the world were still at peace and while only a few of the responsible diplomats were thinking of the possibility of war, the National Bureau of Standards in the spring of 1939 held a meeting with its metallurgical advisory committee. The projects then discussed were: copper-base wrought metals '85-5-5-52'; elastic properties of cast iron; foundry sands; high-purity iron; refractories for use in melting high-purity metals; 'gases' in metals; plastic deformation of metals; pipe corrosion; water-treatment to retard corrosion of steel; weathering of aircraft sheet metals; treatments for improving the permanence of magnesium alloys; roofing materials; painting of steel to be used in building construction; silver research project; high-temperature creep of metals; low-temperature properties of aircraft structural metals — impact resistance; thermal transformations in steel and grain size; quality of carbon steels; weather exposure of aircraft sheet metals; accelerated testing to determine susceptibility of aluminum alloys to inter-crystalline corrosion; does continued fatigue-stressing of a steel below its endurance limit seriously affect the metal; significance of a ductility requirement in specifications for metals; study of torsion-impact tests; soldered joints in copper tube plumbing; improved metallographic technique; fatigue of chromium-plated steel; new micro-hardness tests; oxide coloring of steels; elastic properties of high-strength aircraft structural metals; and standard chemical analytical samples.

Few of these projects, indicative of the present advance in metallurgical practice, were directly allied to war needs. But many of them will be quickened by the war requirements and, while this world catastrophe may prove to be a great loss to humanity, it may yet prove of great benefit to scientific knowledge. In the United States the trends noted have all been towards improving economy and quality. This was especially the case with two improvements in methods announced during the year.

Steel-making Improvements.

In part because the quality of the steel can be more easily controlled during the making, the open hearth method has for years grown in popularity. But the open hearth method is slower than the Bessemer method and therefore more expensive. To offset this, several different methods have been or are being developed for measurement of temperatures of steel in the converter. It was revealed this year that Herbert W. Graham, metallurgist for the Jones & Laughlin Steel Corporation, had perfected a method of control for the Bessemer converters with a photo-electric indicator. This 'electric eye' will judge the color and brilliance of a flame of a Bessemer blow better than a human eye can do, and makes it possible to turn out steel with Bessemer rapidity but of a quality more nearly comparable to that of the open hearth product, particularly with respect to uniformity.

G. Naeser in Germany has also made some contribution to the art of steel-making by using the 'Bioptix' color-pyrometer to measure radiation. This method of observing the changes in temperature and the changes in amount and intensity of the radiation emitted from the surface of molten steel aids in determining what is going on in the bath before casting. It thereby enables any necessary corrective measures to be taken in good time, thus reducing the number of rejections.

Alloys.

Patent rights to produce a cemented titanium carbide alloy in the United States have been acquired by the Firth-Sterling Steel Company. This bears the trade name of cutanit and its manufacture in Europe has paralleled the increase in armament production, since its use in cutting tools may have been given impetus by the manufacture of big guns, rifles, shells and other war materials. It has been indicated that titanium carbide may be effectively added to cemented tungsten carbide materials, thus forming a double carbide of tungsten and titanium. This alloy will relieve our dependence on foreign sources of tungsten.

An increasing use of stainless chromium-nickel steels in aircraft is now logical. The lower specific gravity of the light alloys commonly used is compensated for by the higher strength of the stainless steel which, in conjunction with its corrosion-resistance, enables the latter to be safely used in many thin sections, thus bringing the weight of the completed structure down to an equal basis. Wings, tails, fuselage and under-carriage parts have been made of '18-8' stainless in experimental jobs, and the material has been definitely adopted in production for ailerons, flaps, ribs, tanks, etc. Recent European military planes have standardized on stainless for such parts.

Improved methods have been found to produce high tin bronzes. The corrosion-resisting qualities of the new bronzes are improved, thereby making them particularly useful for many parts of machinery which must withstand both stresses and corrosive attack, such as studs and other fittings on ships' hulls, cocks and valves, and on high-speed motor boats, impellors, shafts and stern brackets.

The few examples here cited afford but a brief outline of the art of metallurgy as it developed during the past year and but a glimpse into the possibilities that are ahead. A long mechanized war in Europe might bring about an acceleration of developments now only beginning. See also CHEMISTRY.