DECEMBER, 1936
INDUSTRIAL AND E N G I N E E R I S G CHEMISTRY
(28) Thompson, J. F., Kent's Mech. Engrs. Handbook, 10th ed., pp.
529-34, New York, John Wiley & Sons, 1923. (29) Vanick, J. S., paper presented before Am. Foundrymen's Assoc., (30)
(31) 33)
(33) (3i)
Birmingham, Ala., 1935. Vanick, J. S., and Merica, P. D., Trans. A m . SOC.Steel Treating, 18, 923-34 (1930). Wadhams, 9.J., Metals Handbook, pp. 1236-9, .4m. Soc. Metals, 1936; Wise, E. M., Ibid.,p. 1272. Worthington, R., Intern. Nickel Co., Inc., Tech. Bull. T-1 (1932). Worthington, R., Ji'arl'ne Eng. & Shipping B g e , Sept., 1931. Forthington, R., X e t n l P r o g r e s s , 24, No. 1, 20-4 (1933).
RECEIVEDOctober i , 1936.
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Discussion I. B. McCORKLE National T u b e C o m p a n y , Pittsburgh, Pa.
I
S ADDITION to problems of corrosion resistance of ferrous
materials and their ability to give satisfactory service a t elevated temperatures, the chemical engineer a t times must employ his materials a t subzero temperature. In general, steels become stronger and less ductile as the temperature is lowered. -Also, as the temperature is lowered, steels in the notched condition show a rapid drop in their ability to absorb energy in the impact test. In the unnotched condition, there is apparently little if any embrittlement due to low temperatures. However, all commercial materials are more or less notched owing to euch causes as threads, too sharp fillets, pitting from corrosion, or even carelessness in handling. Unfortunately there is no way to translate impact values directly into design, so that the engineer in his selection of materials must set himself a more or less arbit,raryvalue. The minimum acceptable value must be the result of experience. Some designers of low-temperature equipment consider as satisfactory a minimum of 10 foot pounds a t the working temperature. Until recently this value could not be met consistently a t -50 O F., for example, even with soft steel, unless it were quenched and tempered. Aside from the expense, heat treating is often impracticable. It has been found that' alloying with nickel will affect considerable improvement. The recent development of the so-called fine-grained steels has led to remarkable improvement in plain carbon steels with respect to low-temperature impacts. There is also indication that the improvement effected by nickel is further enhanced by the fine-grain treatment. For example, t,est results on a 0.15 carbon-0.50 chromium steel showed less than 10 foot pounds a t -50" F., whereas a steel similar in composition, but differing in that it was of the fine-grain type, gave over 120 foot pounds. Considerable advances in the ability to produce steels with good impact properties a t low temperatures may be expected in the next few years. RECEIVED October 9, 1936.
1397
WROUGHT COPPER BASE ALLOYS D. K. CRAMPTON Chase Brass & Copper Company, Waterbury, Conn.
Copper tubes are being increasingly used for all water supplies, for pulp lines in the paper industry, air lines, oil supply lines, vapor lines, etc. Red brass is the preferred material from the corrosion standpoint for most corrosive waters. In the condenser tube field the cupronickels are gaining ground. The silicon bronzes are being increasingly applied in many diverse fields-for instance, tanks, kettles, evaporators, bolts, springs, agitators, etc. One of the latest applications in the paper industry is for Fourdrinier wire. Some of the newer alloys comprise aluminum brass for condenser use and particularly the recent modification containing both tin and aluminum. Antimony is being used in many brasses t o prevent dezincification. An alloy of great promise is nickel-aluminum bronze of rather high nickel and aluminum content. In the welding field, coated rod for metallic arc-welding and nonfuming brazing rod are important accessories t o fabrication of chemical equipment. A recent development is that of composite tubes for withstanding serious corrosion in oil refinery tubes. EVELOPMENTS in alloys as with other products usually take place over a period of years, and startling innovations are seldom brought forth in a short time. Some of the comparatively recent copper alloy developments have to do with extended uses of the well-known established alloys and others are of the nature of new materials. A few examples from each field will be described.
Extended Uses of Older Alloys COPPERTUBES.The metal copper has found many new and enlarged fields of use. With t h e advent of suitable fittings of the flared or sweated type, copper tubes are more widely utilized t h a n formerly. I n the plumbing field this product is highly suited t o most 71-ater conditions and combines all of the
