ISDUSTRIAL A I D EXGIhEERIhG CHEMISTRY
1400
\OL. 78, >\to. 12
solution potential. Also, in productioii no particular annealing, pickling, or scrap dispohal probRocklems arise. Temp. well BriConThe nickel-aluminum bronzes are relatively of B ne11 Elongatrac.4ging (2 Hard- HardYield Tensile tion in tion of new; the precipitation hardening type is particuAlloy Hr.) ness ness Strength Strength 2 In. Area larly useful. Two such alloys are available. I”. Poundslsquare inch % % One contains about 91 per cent copper, 7.5 per 91 Cu, 7.5 Ni, 1.5 91 Not aged 13 cent nickel, and 1.5 per cent aluminum, and 900 87 71,000 99,000 19 40 1000 92 160 t h e o t h e r 82 p e r c e n t copper, 15 per cent 1100 94 165) nickel, and 3 per cent aluminum. The first 82 Cu, 15 Ni,3 A1 Not aged 95 165) so0 102 210 alloy can be extensively worked either hot or 900 104 220 100,000 140,000 5 6 cold and is also capable of considerable precipi1000 tation hardening as shown by the figures in Table 11. It finds auulication in uroueller shafts and s i m i l a r s t r u c t u r e s where a-hard, highan important difference in the action of these two elements strength, tough, corrosion-resistant alloy is necessary. The alloy containing 15 per cent nickel and 3 per cent has only recently been appreciated. When arsenic is added to brasses for dezinciiication resistance, a severe intercrysaluminum is readily hot-worked but can be cold-worked talline type of attack is a p t to result which may be as serious relatively little and then only with difficulty. It is hard and as the dezinci5cation. On the contrary, antimony shows no strong and is quite susceptible to precipitation-hardening such tendency and is, therefore, a safer and more effective treatment. The excellent properties which can be developed are shown in Table I. This alloy finds logical application to remedy than arsenic. These antimony-bearing alloys are the subject of a U. S.patent (allowed but not yet issued). parts of such size and form as to lend themselves to fabrication A recent development appears in connection with condenser hot and where a material is desired with great strength, hardness, abrasion resistance, and corrosion resistance, along and heat exchanger tubes in oil refineries where oil or vapor with ability to be age-hardened. is in contact with one side of the tube and water in contact with the other. A difficult problem results. Extensive An important innovation in the welding field is that OF investigation in the field as well as in the laboratory shows nonfuming brazing rod. For many years large amounts of Muntz metal type rod have been used for brazing, since it i.: that any alloy with high resistance t o aqueous corrosion is particularly well adapted to joining and repairing cast-iron intrinsically vulnerable to attack by sulfur in oils and vice parts. A former objection to the use of this material was the versa. No single alloy appears to be well suited to withstand both types of attack. High-copper alloys, for instance, show excessive amount of zinc fume produced which frequently resulted in considerable discomfort to the welder. Recently excellent resistance t o aqueous attack whereas the low-copper it has been found possible, b y the addition of either beryllium brasses have relatively poor resistance, especially a t the temor silicon to these alloys, to suppress these objectionable peratures involved in oil refinery practice. On the other hand, fumes almost entirely, making the use of such alloys a inore these low-copper brasses have the best resistance to sulfur pleasant and less troublesome occupation. Silicon is mor? attack of any of the copper alloys. T o combat this condition, composite tubes have been deeffective than beryllium in certain ways and is being used extensively in commercial work. veloped with one layer of composition suitable for water Many other new developments in the copper alloy industry resistance and the other suitable for oil resistance. A typical are still in the laboratory stage or a t least not ready for combination now being tested in the field has commercial general exploitation. Time and money are being constantly bronze for the water side and admiralty brass for the oil side. directed to such activities, and the indications are that during This combination of two brasses has certain important adthe next few years even more new and worth-while developvantages for such applications over similar combinations of ments will be brought out than in any similar period in the past. any two less similar materials. For instance, there is only a slight difference in the coefficient of thermal expansion or RECEIVED September 12, 1936. TABLE
11.
PROPERTIES O F NICKEL-.kLUMINUM
RROSZES
*.*.
Discussion W.H.BASSETT, JR. Anaconda Wire a n d Cable Company, Hastings-on-Hudson, N. Y
T
HE chemical industry uses a wide variety of copper base materials, ranging from copper to the ternary alloys, and those containing more than 3 elements. In general these materials fall within eight groups: ( 1 ) electrolytic and deoxidized copper, (2) copper-zinc alloys, (3) copper-nickel-zinc and coppernickel alloys, (4) copper-silicon group, (5) copper-tin alloys, (6) copper-aluminum group (copper-aluminum-iron and copperaluminum-iron-nickel), (7) copper-zinc-aluminum, copper-zinctin, and other special copper-zinc alloys, (8) precipitation hardening alloys, such as copper-nickel-silicon, copper-beryllium, and copper-beryllium-nickel. The increase in the use of some of the older alloys has resulted in great measure from the improvements in the casting and fabricating departments. The use of larger melting units, the improved control during the melting and casting, and the increase
in the weight of the cast bars have resulted in more uniform products generally. Metallurgical control during the rolling and annealing operations has also resulted in the general improvement in the quality of the finished product. These changes have been definitely reflected in the service records of the materials in question. In some cases the same alloy has shown marked increase in its useful life, because of the improved metallurgical practice instituted during the past 15 years. Among the newer alloys, Crampton mentioned the addition of aluminum and tin to an 80-20 copper-zinc alloy. These metals combined with copper have been used successfully for almost every major railroad electrification in the United States. The alloy contains approximately 2.25 per cent aluminum, 1.75 per cent tin, and 96 per cent copper. One of the first installations was that of the Cleveland Union
DECEMREH, 1936
INDUSTRIAL AND E S G I N E E R I N G CHEMISTRY
Terminal electrification. The alloy, together wit,h numerous other ferrous and nonferrous materials, was subjected to accelerated corrosion tests by the technical committee of the -4ssociation of .Lmerican Railroads. These tests showed that the high-copper alloys were very resistant to the corrosive action of locomotive fumes, salt fogs, and other corrosive conditions which were encountered on the railway right-of-way. I n addition to the use by railroads, where the bronze supports the copper feeder cables and the cadmium-bronze trolley wires, the alloy has been used extensively on the west coast, to support, telephone cables where the salt fogs and spray from the ocean destroy the ordinary messenger cables within a few months. The precipitation hardening type of alloy has been used successfully where ordinary materials are readily softened at operating temperat'ure. For example, the valve seats in airplanc motors,
1401
which are constructed from an alloy containing approximately 10 per cent aluminum, 0.5 per cent iron, 0.6 per cent nickel, and the balance copper. Kickel and silicon have also been used as hardening agents in some alloys. Likewise, beryllium copper has been found desirable because of its hardness and nonsparking characteristics. The original copper-beryllium alloy was further improved by the addition of nickel, which resulted in a more uniform and iatisfactory alloy. As Crampton stated in the last pai,agraph of his paper, metallurgists are continually studying the effect of the addition of small amounts of various elements to copper base alloys, and undoubtedly there will be great strides made in this field during coming years. R E ~ E I V EOctober D 9. 1!136.
....
Discussion WILLIAM P. SAUNIER E. hl. Gilbert Engineering Corporation, Reading, Pa.
B
ERYLLIUM, alloyed with copper in varying amounts and with other metals, particularly nickel and cobalt, offers a new series of metals possessing many valuable characteristics. The most widely used is a copper-beryllium alloy containing about 2 per cent beryllium, but several different types. both binary and ternary, have been developed for diffewnt applications, and many more are being inve5tigated. Perhaps the most interesting, as well as moat valuable, charackristic of beryllium is its ability to render a copper alloy heattreatable. By heat treatment a 2 per cent alloy can be given a hardness as high as 380 Bi,inell, and a niaximum ultimate strength in tension of 180,000 pounds per square inch. The simple beryllium copper alloy,- can be heat-treated whether they are used as castings or as rolled sheet or bar stock, and castings can be machined and sheet or Car stock can be completely formed and shaped before heat treatment. Beryllium copper has been available commercially in this country since 1932, and has found application in a variety of services. Its use in springs of all kinds has been particularly outstanding, owing t o the high loading stresses permitted, t,he continued accuracy of calibration, and the high fat'igue strength of the metal. Two other applications of perhaps more interest to chemical engineers are in the manufacture of nonsparking tools, with wear resistance approximating tool steel, and as a material for making cast molds for use in the plastics industry. One of the foremost manufacturers of the country has developed a comprehensivr Get of nonsparking heryllium copper tools
which are meeting a demand for safety tools of high strength, wear resistance, and corrosion resistance. Molds of cast beryllium copper are being used ah dies for forming plastics and metals. The material can be cast to reproduce intricate patterns for which a steel die could be made only at great expense. Such finishing as is required can be done while the casting is in the soft state, and subwquent, heat treatment give< a hard, wear-resistant, surface. The poxsibilitirs in this use of beryllium alloys are great indeed, a? evidrnced hy what has already been clone. Bearings and pears of beryllium copper can be tlesigued fur unit load- much higher than can safely be applied to any other c.ommcrcia1 material. One example of this type of application is its use for the hub cones of adjustable-pitch aeroplane propellers where the conditions require a material of high strength, high resistance to vibration, and the ability t o withstandextremely high bearing load3. Corrosion resistance of beryllium c o p y r , under laboratory test conditions, is about equal to that of deoxidized copper. This was found in a series of tests with salt spray, with alternate immersion in warm 10 per cent sulfuric acid and in hydrochloric acid. -1sea water test of .specimens exposed a t half-tide elevation disclosed that corrosion resistance is unaffected by heat treatment and that, under this kind of exposure, beryllium copper is somewhat more resistant to corrosion than deoxidized copper. In none of these tests was there evidence of intrrgranular penetration. RECEIVEDOctober 9, 1936.
