general suggestions for good foundry practice - H. · PDF file312/226-6600 4-3 wrought...

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Control of Melting AtmospheresWhen melting copper-base alloys in fuel-fired furnaces, proper control of the analysis of the products of combus-tion is very important. Without going into the theory of gases in metals, it can be stated that the copper-base al-loys should be melted under an oxidizing atmosphere. The foundryman has several methods for determining the type of atmosphere which surrounds the metal during the melt-ing operation. These tests are:

1. Visual—a short, sharp flame with a slight green tinge around the outer edge usually indicates an oxidizing atmosphere. However, green flames are not always oxidizing; a long, lazy green flame has been found to be reducing. For this reason, visual determination, unless done by a highly skilled op-erator, is often inaccurate. A yellow, yellowish-red smoky flame is an indication of a reducing atmo-sphere.

2. Orsat or other gas testing equipment gives an ac-curate analysis of the hydrogen, carbon dioxide, carbon monoxide and oxygen in the sample, but the difficulty lies in getting the proper sample. The time necessary to run the test is also a handicap, for the atmosphere may change considerably dur-ing the period, and any changes made in burner controls might make results erroneous.

3. Probably the most accurate qualitative method is the zinc test, due to its simplicity, practicability and speed. A small, clean, cold piece of virgin zinc is held in the flame, just above the liquid bath, for about five seconds. If the zinc turns black, the at-mosphere is highly reducing. If it turns straw yel-low to light gray, the atmosphere is slightly reduc-ing. If it does not change color, the atmosphere is oxidizing. Its very simplicity should permit a test of every furnace immediately after the metal is molten, with correction of the flame, if necessary.

4. Another rapid qualitative test may be accomplished by pushing back the slag or dross on the surface of the metal just after it has become completely mol-ten and observing the appearance of the exposed surface. If the surface stays mirror bright (similar to a pool of mercury), the atmosphere is highly reducing. If the surface becomes cloudy or filmy immediately, the atmosphere is too highly oxidiz-ing. The proper atmosphere is one that causes the exposed surface to become cloudy or film over in three to five seconds. This test should be done at a temperature prior to the vaporization of the zinc as it will completely mask the observation of the surface.

Even though the flame is oxidizing at the point where it leaves the furnace and comes in contact with secondary air, this does not necessarily indicate that it is oxidizing over the surface of the metal, although the possibilities are in its favor. If, however, the flame is reducing when leaving the furnace, it certainly will be reducing over the surface of the metal.

Fracture TestsAn indirect, though a most important method of de-

termining melt quality of the tin bronzes, high lead tin bronzes and the red brasses, is by the fracture of test pieces or actual production castings. The physical appearance of a fractured section is related to melt conditions, pour-ing temperature, mold conditions and gating and risering practices. If the latter two variables could be held relatively constant, then the fractured section could be correlated with gas content and pouring temperatures. The follow-ing is a procedure for acquainting the foundryman in the interpretation of fractures.

Each of the alloys in question should be melted under oxidizing conditions and brought up to an extremely high temperature and poured into some type of bar or one of the regular production castings that can be readily fractured.

GENERAL SUGGESTIONS FOR GOOD FOUNDRY PRACTICE


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The metal should be cooled to 2300°F and the bar or cast-ing poured. Another bar or casting is poured after every 100°F drop in temperature, until the castings are about to misrun. This same procedure should then be repeated with the metal melted under reducing conditions.

It is most important that the fractured sections be examined immediately after the casting or test pieces are broken; otherwise they have a tendency to tarnish after exposure to the air and are apt to be misleading. It is pos-sible to determine the best pouring temperature range, as well as to distinguish between the fracture of castings that have been melted under oxidizing conditions, as against those melted under reducing conditions.

Any attempt to describe to the foundryman the color or texture of the fracture that he should look for would be confusing. Only with experience and close observation can he be taught; but once he gets the knack of interpreting fractures, he has a tool for a quick test of metal quality.

Brass and Bronze Ingots Versus Virgin MetalsH. Kramer & Co.’s quality controlled specification brass and bronze ingot has many advantages, compared to the compounding of virgin metals, to attain the same alloy. H. Kramer & Co. guarantees that its alloy ingot is always within the chemical composition which is specified, and that with normal foundry practice, it will meet the me-chanical and physical properties desired. However, when compounding virgin metals to make the same alloy, it is necessary to weigh each item separately, and any mistakes in weighing will result in an alloy that is outside of the composition limits desired. In many cases, when using virgin metals, it usually becomes necessary to add harden-ers, which becomes an added cost.

It is well known that ingot metal is less sensitive to gas absorption than the melting of the individual com-ponents. When using virgin metals, the original melt is frequently heterogeneous and it may be necessary to pig, analyze and remelt to get homogeneity, which will add extra laboratory and melting costs.

Guaranteed composition of ingot metal obviates the

necessity of extensive laboratory facilities that would be necessary in the use of virgin metals. Possibly the great-est advantage of using ingot alloys over virgin metals is economics. Most alloys are sold at a price below the virgin metal component prices.

Segregation of AlloysAs more and more copper-base alloy castings are sold to meet definite chemical and physical specifications, the pro-duction of such castings utilizing foreign scrap* becomes increasingly more difficult. Contamination of scrap with elements that cause leakers, unsoundness and bad finish is increasing, and the use of this contaminated material to make castings of high quality cannot be justified under any circumstances in a well-run foundry.

For example, at one time, most sleeve bearings were made from the copper-tin-lead alloys; however, today, sleeve bearings are also being made from aluminum bronzes, manganese bronzes, silicon bronzes and cast-iron or steel-backed babbitt lined bushings. Usually, the surfaces of these scrap castings are dirty or covered with grease and sometimes painted, which makes them virtu-ally impossible to differentiate without the aid of complete laboratory equipment and experienced personnel.

Brass and bronze scrap returning to the market today is composed of many complex alloys and alloy assemblies that cannot be thoroughly sorted and separated to be of any value in the production of castings. Such elements as aluminum, silicon, manganese, titanium, cadmium, mag-nesium, chromium, and others are being alloyed with cop-per and are now getting into scrap and are almost impos-sible to separate by economical sorting procedures.

Brass and bronze valves, which at one time were nor-mally made from copper-tin-lead-zinc alloys, are now returning in scrap from many different types of alloys: yellow brass, tin bronze, aluminum bronze, manganese bronze, silicon brass and silicon bronze, nickel alloys and ferrous alloys. Valve stems are being made out of cast and

*Foreign scrap is that purchased from sources outside the foundry (such as scrap dealers). Domestic scrap is that generated in the foundry (gates, risers, reject castings and turnings) that may be used without difficulty if kept segregated, clean and dry.


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wrought products which may be manganese bronze, alu-minum bronze, Tombasil and various copper-nickel or nickel-copper alloys. The same holds true of discs and seats in the valve. These are extremely difficult to hand sort in any economical fashion. Radiators, in addition to having a great percentage of non-metallic accretions have significant amounts of iron adhering, both externally and internally. In addition, radiator fins made of aluminum and stainless steel are also appearing on the market. It is virtually impossible to sort yellow brass so that it is entirely free of aluminum and silicon. Condenser tubes, which at one time might have been normally copper-zinc alloys, with small additions of tin, are returning in a myraid of alloys, containing aluminum, arsenic or an-timony. Aluminum bronze, many variations of copper-nickel, monel and stainless steel alloys are also used for condenser tubes.

The above examples merely illustrate in a small way the types of impurities that can be involved in the usage of scrap for the making of castings. It may be concluded that it would be expensive and dangerous in the long run to use foreign scrap in the production of copper-base alloy castings.

Only a competent ingot manufacturer can pro-duce quality ingot from such complex raw materials. Certainly the foundry is completely lacking in the es-sential facilities to substitute the complex assortment of foreign scrap for quality ingot. It is both uneco-nomical and hazardous for the foundry to use scrap because it is not enough simply to sort and grade the raw material and later select certain grades to remelt. On the contrary, the production of quality metal re-quires scientifically controlled smelting and refining processes, under the supervision of trained metallur-gists and chemists.

These refining processes are not commercially feasible in small furnaces, but require large furnaces, handling quantities of 100,000 pounds or more.

The usual practice is to melt a large tonnage at one time, re-fine the heat by the use of proper fluxes and slag-forming mate-rials under the strictest metallurgical controls, analyze the heat

while in the molten state, make the necessary metal additions to adjust to the desired composition, deoxidize the heat as may be necessary and then cast the metal into ingot. Sample ingots, per-iodically set aside during the casting cycle, are drilled to ob-tain a final chemical analysis.

The entire cycle is then supplemented with physical and mechanical tests and metallographic examination. A high quality product is thus assured.

Not only is the metal coming into the foundry consid-ered raw materials, but the foundry returns and domestic scrap must also be considered raw material.

Foundry return scrap must be very closely segregated by alloy in order to avoid contamination, as most of the alloy groups are incompatible with one another. For ex-ample, if aluminum bronze, manganese bronze or silicon bronze is mixed with red brass, it will reduce the mechan-ical properties and pressure tightness to such a degree that the red brass castings would be rendered almost useless. Conversely, if the aluminum bronzes, manganese bronzes or silicon bronzes are contaminated with any of the leaded bronzes, serious reduction in mechanical properties results. Careful housekeeping of charge make-up area, cleaning room, and machine shop is a must if contamination is to be kept to the minimum.

As an example of one class of copper alloy being con-taminated with another, small pieces of aluminum bronze and silicon bronze were intentionally added to heats of a high lead in bronze, 80-10-10.

As shown in Figures 1, 3, and 4 aluminum and sili-con cause considerable unsoundness in sand castings made from the bearing alloys. This unsoundness, in turn, causes a considerable weakening of the casting, as illustrated by the listed tensile properties (see page 4-4). Further weak-ening results if the bearing should become overheated, which may result in cracking and subsequent failure of the bearing.

Aluminum and silicon also form their oxides readily in the molten alloy. These oxides then become entrapped in the castings and are considerably harder than the base metal. If these hard particles are on the bearing surface, considerable damage to the shaft may occur.


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The introduction of small amounts of aluminum and/or silicon will completely destroy the physical properties of the 80-10-10 and red brass type alloys. The amount of alu-minum and silicon necessary to seriously affect the prop-erties has not actually been determined, but it is believed that as low as 0.01 per cent of either will markedly reduce

the properties and pressure tightness. The Society of Auto-motive Engineers, American Society for Testing Materials and the brass and bronze ingot manufacturing industry have set limits of 0.005 per cent on both silicon and alu-minum for this alloy.

CHEMICAL ANALYSIS

A.S.T.M. SPEC. 80-10-10 No. (a) Silicon 80-10-10 No. (b) Alum. 80-10-10 No. (c)

Copper 78.00 - 82.00 80.01 80.36 79.98Tin 9.00 - 11.00 9.24 8.90 9.10Lead 8.00 - 11.00 9.63 9.59 9.85Zinc .75 Max. .43 .46 .50Iron .15 Max. .03 .02 .04Antimony .50 Max. .19 .19 .18Nickel .75 Max. .29 .29 .30Aluminum .005 Max. None None .03Silicon .005 Max. None .033 None

TENSILE STRENGTH RESULTS

Tensile Strength p.s.i. 34 ,000 Min. 34,000 12,650 20,050Yield Strength p.s.i. 16,300 11,700 17,000% Elongation in 2” 22.0 26.0 3.0 4.0Fracture of Test Bar Blue-gray center flecked 95% Orange. 40% Orange. with yellow specks. Fine. Very coarse dendrites. Very coarse dendrites.


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Fig. 1

Fracture Characteristics of Bearing Alloy with Silicon and Aluminum.Description of Fractures:

a. Normal 80-10-10, Blue-gray color with slight yellow specks in center portion. Structure is dense.

b. 80-10-10 with 0.03% Silicon; blue gray rim 1/8” thick. Cen-ter portion is orange. Structure is dendritic and very coarse.

c. 80-10-10 with 0.03% Aluminum, Blue-gray rim 1/8” thick. Center portion is mottled orange and gray color. Structure is dendritic and very coarse.

Fig. 2

80-10-10 contaminated with various amounts of SiliconUpper left — No SiliconLower left — 0.03% SiliconUpper right — 0.01% SiliconLower right — 0.10% Silicon

a b c

Fig. 3

Photo-micrograph of regular 80-10-10 showing normal distri-bution of the lead particles in the copper-tin alloy matrix. Mag-nification X100. Not etched.

Fig. 4

Photomicrograph of 80-10-10 Contaminated with either Alumi-num or Silicon. The gray islands are the lead particles. The dark connected channels are interdentric porosity. This structure is typical of that obtained in the leaded bronzes when contami-nated with either Aluminum or Silicon. Magnification X100.


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The basic metallurgy and foundry practice for tin bronzes, leaded tin bronzes and red brasses are very similar and will be discussed as a single group.

General MetallurgyTin bronzes are alloys of copper and tin, with or without zinc, with nickel additions when used in the manufacture of gears. Tin bronzes have excellent wear and corrosion resistance. They are used for valve and pump bodies, steam fittings, paper machinery, piston rings, bearings and impellers. An alloy of eighty percent copper and twenty percent tin is used for bells because of its exceptional tonal qualities.

Leaded tin bronzes have essentially the same applications as tin bronzes except for a small lead addition to improve machinability. Some leaded tin bronzes are used for bearings and bushings. The load carrying capability of these alloys varies with the copper and tin content. Lead, because it is insoluble, is finely dispersed in the base alloy, providing lubrication and embedability. Alloys in this group are used in machine tools, electrical machinery, railroad cars, diesel engines, gasoline engines and in bearings where acid resistance is essential

Red brasses (and semi red brasses) are combinations of copper, tin, lead and zinc that offer excellent strength, corrosion resistance, machinability and foundry characteristics at a relatively low cost, thus making them the most widely used of all copper based casting alloys. Most plumbing goods, valves and fittings, marine hardware, ornamental and statuary castings, pump bodies and impellers, water meters and other general castings are poured from this group of alloys.

Foundry PracticeAny furnace type can be used to melt these alloys. Proper precautions are indicated to insure safe and smooth operations. Gas fires furnaces must maintain proper combustion. Usually, the most consistent results for these alloys are achieved by melted as rapidly as possible,

at a temperature only slightly above what is necessary for pouring, in a slightly oxidizing atmosphere (see pg. 4-1 Control of Melting Atmosphere). For large intricate castings, it is beneficial to superheat the metal 200F to 300F degrees and allow to air cool to reduce gas content. Metal should be poured as soon as it is ready.

15% Phosphor Copper is used as a deoxidizer for this alloy group. The recommended quantity is two to four ounces for alloys containing less than 8% Zinc, and one to two ounces for those with higher Zinc content. Phosphor Copper can be stirred into the ladle or, in tilting furnaces, it can be introduced into the

stream after 20 to 25% of the ladle has been filled. Zinc additions made to replace Zinc lost during the melting cycle may be made along with the Phosphor Copper.

A pouring temperature between 1950F and 2250F is satisfactory for most castings, but those with extremely thin walls may require temperatures at or above 2300F. Whatever the situation, temperatures should be kept as low as possible but still sufficient to avoid misruns or internal shrinkage. The lip of the ladle should be as close as possible to the sprue opening, keeping the sprue full and ensuring an uninterrupted stream. It is recommended that reliable calibrated pyrometers be employed to help control pouring temperatures.

This group of alloys solidifies over a wide range of temperatures. Foundrymen must employ a variety of techniques; chills, insulated risers, hot-top compounds and gating practices, to insure proper directional solidification. A thorough study of each casting will reveal the best types and optimal locations for gates, risers and chills. Whenever possible, arrange the gating so that the riser feeds directly from the gate and receives the last metal to enter the mold.Sand permeability can range from 25 for small, thin-walled castings to as much as 100 for large, heavy-wall ones. Whatever the permeability requirements, moisture control is of paramount importance. Proper venting is also essen-

RED BRASSES AND TIN BRONZES


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tial to reduce pressure on the core and protect the casting from gas buildup. Care must be exercised to prevent the core from becoming too hard to prevent cracked castings and knockout difficulty. The yellow brass alloys are used mostly where their characteristic yellow color is desired or

where a low-cost alloy can be used. These alloys also have good polishing and machining qualities and this, coupled with their low cost, makes them attractive to the hardware and plumbing industries.

SUMMARY OF RECOMMENDED FOUNDRY PRACTICES

1. Melt rapidly under oxidizing atmosphere

2. Do not hold in furnace longer than necessary

3. Metal not to be heated more than 150°F melting temperature

4. Add zinc where required

5. Add appropriate amount of Phosphor Copper

6. Skim carefully and avoid vigorous stirring

7. Take accurate temperature readings

8. Pour at lowest temperature that will protect against misruns and internal shrinkage

9. Keep sprue full at all times

10. Provide adequate gates and risers

11. Maintain sand properties


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The yellow brass alloys are used mostly where their character-istic yellow color is desired or where a low-cost alloy can be used. These alloys also have good polishing and machining qualities and this, coupled with their low cost, makes them attractive to the hardware and plumbing industries.

General MetallurgyIn general the strength of yellow brass increases as the cop-per decreases. At the same time the ductility decreases. Tin, present up to 1.5 per cent, normally helps to increase the strength and hardness, while at the same time improves ma-chinability and corrosion resistance. Lead, also added up to 4 per cent, improves machinability and polishing properties.

Yellow brasses are used principally in the hardware and plumbing industries. Specific examples are andirons, door knobs, escutcheons, band instruments, lamp fixtures, locks, ornamental parts, furniture hardware, plaques, valves, faucets, ferrules, and fittings.

Foundry PracticeAny of the furnaces used for melting the copper base alloys may be used for melting the yellow brasses. Zinc losses may be encountered in open-flame furnaces. Even though the yellow brass alloys are not as susceptible to gas pickup as the other copper-base alloys, it is recommended that melting be carried out under a slightly oxidizing atmosphere.

Due to the large amount of zinc present in the yellow brasses, little or no deoxidation is required. However, to improve the fluidity of these alloys, aluminum or phospho-rus is added. (Aluminum and phosphorus should never be used together). Phosphorus is used where the sections are thin and the casting is required to be pressure tight. Alu-minum is used when there are no pressure requirements and a smooth surface appearance is desired. Zinc should be added to replace that lost in melting.

In general, a pouring temperature of approximately 2050°F is adequate for most castings. Above this tempera-ture, zinc will flare profusely and may cause dirty castings. However, if the sections are thin and the casting has no pressure requirements, a higher temperature may be used adding aluminum to control flaring.

The gating practice for yellow brass is similar to that of the red brasses. The sprue, gate and runner should be slightly larger, to insure that the mold cavity fills as rapidly as possible to prevent any zinc oxide forming dirt or holes on the surface of the casting. Vent the end of the casting to insure relief of back pressure.

Generally, only small castings are made from yellow brass and fairly fine sands may be used. Sand should be dry to prevent boiling action against mold faces causing drossy appearance on casting surfaces.

LEADED YELLOW BRASSES


1. Melt rapidly and do not heat to more than 100°F higher than the desired pouring temperature.

2. Add zinc to replace that lost in melting.

3. Add 0.10 per cent to 0.30 per cent aluminum for castings not required to be pressure tight. Add 1 ounce of 15 per cent Phosphor Copper per hundred pounds of melt for castings required to be pressure tight. It is important to remember that phosphorus and aluminum are never to be used together.

4. Pour with as little turbulence as possible.

5. Sand should be kept dry, taking care to ram mold evenly.

6. Sprue, runner and gates should be of adequate size to fill mold cavity rapidly.


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General MetallurgyManganese bronze (or more correctly, high strength yellow brass) combines high tensile strength and yield strength with relatively good corrosion resistance. This group of al-loys is basically copper and zinc to which various propor-tions and combinations of aluminum, manangese, iron, tin and nickel are added. Lead is sometimes added to im-prove machinability.

Aluminum is added in the range of 0.5 per cent to 7.5 per cent and is the principal strengthener of the alloy group. Manganese varies from 0.2 to 4.0 per cent and iron from 0.5 to 4.0 per cent and act as grain refiners. Tin, up to 1.0 per cent and nickel up to 3.0 per cent are added mainly to increase corrosion resistance.

Tensile strengths on the order of 125,000 psi and yield strengths of approximately 90,000 psi may be obtained on castings without further thermal treatments. To obtain

consistently high mechanical properties, the composition must be closely regulated and controlled. Many elements are undesirable and affect the properties adversely, thus limiting the raw materials for the manufacture of the man-ganese bronzes to only those of the highest purity.

Variations in the major alloying elements greatly af-fect the mechanical properties obtainable from the man-ganese bronzes. The primary consideration when melting is to maintain the proper copper-zinc ratio. Zinc loss from remelting ingot and foundry returns must be addressed.

Variation in the Copper Zinc ratio will cause devia-tion in chemical properties as illustrated by the informa-tion for alloy C86500 (Kramer A Manganese Bronze) in the chart below. Minimum requirements are:

Tensile Strength 65,000 psi Yield Strength 25,000 psiElongation 20%

MANGANESE BRONZES

T.S. Y.S. % El. BHN (3000Kg)Fig. 5 56.01% Cu. 83,000 33,000 18.0 157Fig. 6 57.28% Cu. 79,000 32,000 22.5 146Fig. 7 58.47% Cu. 73,000 28,000 32.0 131Fig. 8 59.73% Cu. 68,000 26,000 40.0 116Fig. 9 61.30% Cu. 63,000 23,000 51.0 105Fig. 10 63.46% Cu. 58,500 20,000 57.0 90 (All photomicrographs X100)

Fig. 5 Fig. 6

Fig. 7 Fig. 8

Fig. 9 Fig. 10


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These mechanical property results make it clear why it is necessary to control the copper-zinc ratio. At low copper content, elongation is too low, and at high copper content, tensile and yield strengths are too low.

The following series of manganese bronze alloys il-lustrates the variation in microstructure and mechanical properties caused by variations in the major alloying ele-ments. This series illustrates the many types of manganese bronzes made by H. Kramer & Co.

The relatively good corrosion resistance and high strength of the manganese bronze alloys has made the group one of the most widely used alloys for marine appli-cations—propellers, rudder posts, and other marine hard-ware. Other uses include ball bearing races, rolling mill bearings, gears, impellers, valve stems and many structural castings.

As a note of caution, the use of the single beta phase high strength manganese bronzes should be avoided in certain corrosive media such as sea water, ammonia, acids and liquid metals such as tin, lead, mercury, babbit and solder. The beta manganese bronzes are subject to crack-ing when the alloy is stressed while in contact with these corrosive media. The dual phase or alpha-beta manganese bronzes are less susceptible to this phenomenon.

Kramer “XX” Manganese Bronze (X100)

Cu 61.23 Al 5.40Fe 2.66 Zn RemainderMn 3.80

T.S. 120,000Y.S. 72,000%EL. 18.8BHN (3000Kg) 230

THE BASE ANALYSIS FOR THE SERIES:

Cu 56.00 to 63.3 Fe 1.50 Al 1.05 Mn .45 Zn Balance

Kramer “F55” Manganese Bronze (X100)


T.S. 98,000Y.S. 49,000%EL. 20.0BHN (3000Kg) 188

Fig. 12Fig. 11


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Foundry PracticeAlthough manganese bronzes are not as susceptible to gas pickup while melting as the other copper-base alloys, it is still recommended that they be melted under a slightly oxi-dizing atmosphere. Considerable care should be taken to avoid contamination by other copper alloys as the mechan-ical properties will be greatly impaired. Melt fast, prefer-ably bringing the metal to the temperature where zinc just begins to flare.

No deoxidation is required for manganese bronzes. In order to maintain a correct balance between the copper and zinc, usually 0.5 to 1.5 per cent of high purity zinc is added. The amount added is a function of each individual foundry’s melting practice.

The pouring temperature is usually a function of type and size of casting being poured. This type of metal should be poured just below that temperature where zinc fumes are coming off the surface of the liquid metal. Low

Kramer “X” Manganese Bronze (X100)


T.S. 94,000Y.S. 44,000%EL. 22.0BHN (3000Kg) 175

Kramer “AX” Manganese Bronze (X100)


T.S. 84,000Y.S. 42,000%EL. 20.0BHN (3000Kg) 155

Kramer “SX” Manganese Bronze (X100)


T.S. 93,000Y.S. 48,000%EL. 20.0BHN (3000Kg) 180

Fig. 13

Fig. 14 Fig. 15


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strength manganese bronze flares at about 1850°F while the high strength alloys flare closer to 1950°F.

Due to the aluminum oxide skin on these alloys, pour-ing should be done with as little turbulence as possible, that is, pour evenly and as free from splashes, surges and stops as possible. The gating system should be designed to give an even flow of metal with no sharp changes in direc-tion or restrictions to cause squirting. On many large cast-ings reverse horn gates are used to bring the metal into the mold cavity slowly and quietly from underneath the cast-ing. These instructions are very important and will largely eliminate dross and oxide from being trapped in the cast-ing or on its surface.

The location and size of risers cannot be universally stated, but they are very important. It is necessary to have additional risers, of increased size, over that required by the tin bronzes and red brasses in order to overcome the piping type shrinkage of the manganese bronzes.

Considerable latitude is permitted in the types of molding sands used for the manganese bronzes. The film of aluminum oxide gives a fair finish even when coarse sands are used. The sands for these alloys should be kept dry to prevent the formation of surface drossing. Cores should be thoroughly baked and vented to prevent gas po-rosity in the castings.


1. Melt rapidly and do not heat to more than 100°F higher than the desired pouring temperature.

2. Add zinc to replace that lost in melting.

3. Add 0.10 per cent to 0.30 per cent aluminum for castings not required to be pressure tight. Add 1 ounce of 15 per cent Phosphor Copper per hundred pounds of melt for castings required to be pressure tight. It is important to remember that phosphorus and aluminum are never to be used together.


5. Sand should be kept dry, taking care to ram mold evenly.

6. Sprue, runner and gates should be of adequate size to fill mold cavity rapidly.


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General MetallurgyAluminum bronzes consist of a group of alloys of cop-per and aluminum with iron, nickel or manganese added for the enhancement of specific properties. These various combinations offer alloys of high strength, hardness, wear resistance, fatigue strength and excellent corrosion resis-tance. Aluminum bronzes are also well suited for service at elevated temperatures—higher than for any other group of cast copper-base alloys.

Typically, these alloys contain from 8.0 to 12.0 per cent aluminum and up to 5.0 per cent each of iron, nickel or manganese. Increasing the aluminum content causes a progressive increase in the tensile strenth, yield strength and hardness with an accompanying decrease in ductility. Tensile strengths of over 100,000 psi may be reached in the as-cast alloy.

Aluminum bronzes, in addition to being cast in vari-ous types of sand molds, have found wide application as castings made by the centrifugal, pressure die, plaster and permanent mold processes.

Alloys with over 9.5 per cent aluminum respond to heat treatment similar to that given steel. Heat treatment consists of a quench from 1550° to 1750°F followed by a draw at 800° to 1200°F. The temperature of the draw must be selected in respect to the chemical composition in order to give the correct or specified combination of strength, hardness and ductility.

On those aluminum bronzes with over 9.5 per cent aluminum and with only small additions of iron, nickel or manganese, care must be taken to remove the casting from the mold before black heat is reached in order to avoid em-brittlement. Slowly cooled castings undergo what is termed “self-annealing” and may produce a coarse structure with greatly reduced properties. Rapid cooling from red heat or the addition of iron, nickel or manganese will tend to minimize the problem of self-annealing or embrittlement.

The effect of self-annealing is illustrated in the accom-panying photomicrographs. Comparing Figures 16 and 17 that have been heavily etched, it is difficult to determine the reason for the difference in properties. However when lightly etched as shown in figures 18 and 19, the reason for the dif-ference becomes apparent. Slow cooling through the critical temperature allows the beta constituent to decompose and form the alpha-gamma eutectoid which strengthens the al-loy to a higher degree than does the beta constituent. Figure 20 shows the alpha-gamma eutectoid at X 1500.

ALUMINUM BRONZES

89-1-10 (10.4% Al) X50

Fig. 16 and 18 Fig. 17 and 19 Casting removed from sand Casting allowed to cool 15 min. after pouring in sand to room temp.

76,000 T.S. 64,000 28,400 Y.S. 33,700 17.0 %EL. 8.0 150 BHN (3000Kg) 155

Fig. 16 Fig. 17 Fig. 18 Fig. 19


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Heat treatment changes the appearance of the as-cast alloy microstructure to a much finer structure. (Fig. 21). The tensile strength, yield strength and hardness have been increased considerably over the as-cast properties.

In the Nickel Aluminum bronzes, the general pattern of the alpha-beta structure is the same as in the 89-1-10 alloy except for the reduction in particle size of the alpha (Fig. 22). The peppery effect, as shown in Fig. 22 at X 1500 is a nickel-aluminum compound which contributes greatly to the change in properties.

The aluminum bronzes are used where strength, hard-ness, ductility, wear resistance, bearing properties and cor-rosion resistance are required. Specific uses include wear plates and guides, dies, valve seats, gears, rolling mill bear-ings and slippers, ball bearing races, non-sparking tools, marine propellers and pumps.

Foundry PracticeThe aluminum bronze alloys should be melted under a slightly oxidizing atmosphere. Lift-out crucible furnaces are preferred, although tilting type furnaces may be used,

with care being taken to avoid extreme turbulence during transfer from the furnace to the ladle. The charge should be carefully inspected to avoid contamination with other classes of copper alloys as the properties may be greatly impaired. Add 0.5 per cent of H. KRAMER & CO. NO. 77 ALLOY (Aluminum Bronze Deoxidizer and Degassi-fier) by stirring into the melt approximately three to five minutes before pouring. (See page 4-22—for procedure).

After removal from the furnace and skimming care-fully, the metal should be allowed to cool down to the low-est temperature that will satisfactorily allow filing of the mold. Proper pouring temperature depends entirely on the size and thickness of the casting, although 2100°F may be considered as an average pouring temperature.

Due to the aluminum oxide skin on these alloys, pour-ing should be done with as little turbulenceas possible—that is, pour evenly and as free from splashes, surges and stops as possible. The gating system should be designed to give an even flow of metal with no sharp changes in direc-tion or restrictions to cause squirting. On many large cast-ings reverse horn gates are used to bring the metal into the

Same sample as in Fig. 15

This photomicrograph shows the alpha gamma eutectoid at high magnification (X1500). The pearlitic type struc-ture is typical for this alloy when slowly cooled.

89-1-10 (10.4% Al) X50

1650° F—Water Quenched1200 F°—Water QuenchedT.S. psi 91,000Y.S. psi 37,500%Elong. 11.0BHN (3000Kg) 175

Fig. 20 Fig. 21


4-15

mold cavity slowly and quietly from underneath the cast-ing. These instructions are very important and will largely eliminate dross and oxide from being trapped in the cast-ing or on its surface.

The location and size of risers cannot be universally stated, but they are very important. It is necessary to have additional risers of increased size over that required by the tin bronzes and red brasses in order to overcome the piping type shrinkage of the aluminum bronzes.

Molding sand should be rather open and kept on the dry side to prevent the formation of surface dross due to the boiling of water vapor through the metal. On large castings it has been found advantageous to use ceramic gating systems to prevent the pickup of mold gases and to avoid dross formations. Extra venting of the mold should also be provided. Cores should be thoroughly baked and vented to prevent gas porosity in the castings.


1. Melt under slightly oxidizing atmosphere.

2. Deoxidize and degassify with 0.5% H. KRAMER & CO. NO. 77 ALLOY. (See page 4-22).

3. Skim carefully, avoiding excessive agitation of the metal surface.

4. Pour at as low a temperature as possible.

5. Pour with as little stopping and splashing as possible.

6. Design gating for least amount of turbulence.

7. Provide risers at locations and of adequate size to overcome piping.

8. Molds should be relatively dry and thoroughly vented.

Nickel Aluminum Bronze (10.4% Al) X100 Nickel Aluminum Bronze (10.4% Al) X1500

T.S. psi 106,000Y.S. psi 45,500% Elong. 11.5BHN (3000Kg) 203

Fig. 22 Fig. 23


4-16

General MetallurgyThe term nickel silver usually is applied to alloys of copper and zinc containing considerable amounts of nickel. For many years these alloys were known as “German Silver.”

Nickel silver alloys are known particularly for their excellent corrosion resistance and whitish color and they have superior resistance to tarnishing.

In general as more nickel is added to copper-zinc al-loys, corrosion resistance is increased while color becomes whiter. At the same time, as nickel content increases me-chanical properties are improved. Tin, found in most nickel silver alloys, helps to improve corrosion resistance and castability while aiding in increased hardness and strength. Lead is added to these alloys for improved pres-sure tightness and machinability.

Nickel silver alloys have mechanical properties ex-celled only by the high strength brasses and bronzes. Their tensile strengths range up to 65,000 psi, yield strengths to 30,000 psi, and elongations to 30 per cent.

These alloys are used in corrosion resisting applica-tions such as dairy and food machinery parts, soda foun-tain and restaurant kitchen equipment, plumbing fixtures, steam fittings, valves and valve seats for elevated tempera-tures, pump parts, business machine parts, ornamental and decorative hardware for marine and building applica-tions, jewelry, and statuary.

Foundry PracticeThe melting and pouring practice for nickel silver is similar to that of the other copper-base casting alloys, except that the higher melting and pouring temperatures required ne-cessitate the use of proper melting equipment. As for all the copper alloys, nickel silver should be melted under a slightly oxidizing atmosphere. The best results are obtained by rapid melting and not holding the metal in the molten condition longer than the time required to bring the metal to the prop-er pouring temperature. Slow melting or long exposure of the metal to the fuel gases causes an absorption of gas, which may cause considerable gas porosity in the casting.

Glass is often used as a cover when melting nickel sil-ver alloys high in zinc, such as the 57-2-9-20-12 and 60-3-5-16-16, in order to prevent the loss of alloying elements by vaporization and/or oxidation.

The deoxidation of nickel silver is a very important step in the production of good castings. It is recommend-ed that an addition of 1/2-1 per cent of H. KRAMER & CO. NO. 66 ALLOY be made about three minutes before pouring. The NO. 66 ALLOY should be plunged to the bottom of the pot or stirred in quickly in order to prevent its loss by burning on the surface of the molten metal. (See Pg. 4-22 for procedure).

The metal should be poured very hot, keeping the sprue filled. About 2450°F is the average pouring temperature for

NICKEL SILVER ALLOYS


1. When melting nickel silvers high in zinc, add broken glass to bottom of pot at the start of melt. Melt oxidizing and rapidly and do not hold longer than necessary. With the high nickel, low zinc alloys, use of glass is optional.

2. After melting, add a little more broken glass to harden the slag; push slag to one side.

3. Add 1/2 percent H. KRAMER & CO. NO. 66 ALLOY, three minutes before pouring. (See Pg. 4-22).

4. Push slag to one side and pour metal very hot, keeping sprue filled.

5. Provide heavy gates and risers to feed heavy sections of castings.

6. Molds should be relatively dry and thoroughly vented.


4-17

the higher nickel content alloys (20 and 25 per cent nickel). For the nickel silvers with lower nickel and higher zinc an average pouring temperature of 2250°F will usually suffice. It cannot be stressed too strongly that much better results are obtained when nickel silvers are poured at a sufficiently high temperature. The tendency will be to pour at too low a temperature and for this reason pyrometer control is defi-nitely recommended and should be used.

Because of the relatively high shrinkage of the nickel

silver, liberal sized gates and risers should be used. Precau-tions should be taken in locating risers to assure the hottest metal will be in the risers after pouring the mold in order to obtain directional solidfication.

Molding sand should be fairly open and kept on the dry side. When pouring castings with fairly heavy sections, thorough venting of the mold is a necessity. Cores should be thoroughly baked and permeable enough to prevent gas porosity in the castings.


4-18

General MetallurgyCasting alloys of copper containing silicon (silicon bronzes and brasses) are widely favored for corrosion-resisting ap-plications because of their excellent foundry properties.

In the as-cast condition, microstructures of the cop-per-silicon alloys consist of copper-silicon solid solution matrix with a silicide compound depending upon the sili-con content and alloying elements present. The mechanical properties of these alloys depend directly upon the amount of this silicide compound precipitated during solidfication. In general the greater amount of silicide present the harder and less ductile the alloy becomes.

Commercial copper-silicon foundry alloys generally contain from 3 to 5 per cent silicon with tin, manganese, iron or zinc added to enhance properties. Depending on the proportions of alloying ingredients present, mechani-cal properties range from 45,000 to 75,000 psi in tensile strength; 15,000 to 40,000 psi, yield strength; and 15 per cent to 75 per cent elongation.

Copper-silicon alloys are generally divided into two classes, namely silicon bronze and silicon brass. Silicon bronzes are generally defined as those copper-base alloys containing over 0.5 per cent silicon and less than 5 per cent zinc except that the copper content shall not be over 98 per cent. Silicon brasses are defined as those copper-base alloys containing over 0.5 per cent silicon and over 5 per cent zinc.

Silicon brass, better known as H. Kramer & Co. TOMBASIL, is not only cast into green sand molds, but also used for permanent molding, die casting and plaster casting processes. TOMBASIL’s low melting temperature, 1680°F, makes it excellent for such processes as mentioned above where pouring temperatures in the range of 1700°-1850°F are required. In the case of permanent molding and die casting, this improves die life and makes this alloy the best of the copper-base alloysin this respect.

Copper-silicon alloys have excellent atmospheric cor-rosion resistance and as such are used for such casting applications as memorial markers, electrical switch-gear

hardware, catenary hardware for electrified railroads, and bells. Chemical corrosion applications for these alloys are pump impellers and pump bodies, valves, valve stems, and marine propellers. Copper-silicon alloys can be used in general for elevated temperature applications up to 500°F and for such structural applications as gears and rocker arms.

Foundry PracticesCopper-silicon alloys should be melted under a slightly oxidizing atmosphere. In regard to silicon bronzes, the presence of a reducing atmosphere brought about by insufficient air supply may result in a large amount of gas porosity in the castings because of the high susceptibil-ity of these alloys to gas pickup while melting. Silicon brasses, due to their higher zinc content, are only slightly susceptible to gas porosity. As is true with all copper-base alloys, metal should not be held in the furnace after proper temperature is reached. These alloys can be melted in any of the standard furnaces used for the copper-base alloys, but in all cases be sure that the furnace atmosphere is not reducing.

For the best and most consistent results, the silicon bronzes should be heated to a temperature approximately 200°F to 250°F above the desired pouring temperature. KRAMER NO. 77 ALLOY should then be added. (See Pg. 22-Section 4.) The metal is removed from the furnace and allowed to cool by standing in air to the desired pour-ing temperature. Large heavy castings should be poured between 1800° and 1900°F and small castings between 1950° and 2050°F. Test bars should be cast at approxi-mately 1850°F. TOMBASIL may be poured approximate-ly 100° cooler, and need not be superheated.

Metal should be poured slowly with as little turbu-lence as possible. In general, the metal should enter the mold cavity near the bottom and with the least amount of splashing or squirting. Gates are preferably placed at heavier sections, where it is possible to use risers which will contain the hottest metal when pouring has been

TOMBASIL® AND SILICON BRONZE


4-19

completed. The risers should be a mean of what would be used in making tin bronzes and manganese bronzes; that is not as small as in tin bronzes and not as large as for manganese bronzes, but about half way between.

For the copper-silicon alloy castings, the best results

are obtained with a fairly open syntheyic sand with a moisture content of not more than 4 per cent Any good core sand mixture is satisfactory, providing it has plenty of permeability and is sufficiently soft to take care of heavy shrinkage areas of the mold and casting.

Typical micro structure of Tombasil® (X100)

Fig. 24


1. Melt oxidizing and do not hold longer than necessary.

2. For Silicon Bronzes add 1/2 per cent of KRAMER NO. 77 ALLOY about 3 minutes before pouring. For TOMBASIL there may be occasions where the addition of KRAMER NO. 77 ALLOY will prove beneficial. Here it should be added in the same manner as mentioned above for silicon bronzes. (See Pg. 4-22).

3. Pour at as low a temperature as possible.


5. Gates and risers should be larger than those used for tin bronzes, but smaller than those used for manganese bronzes.

6. Use a fairly open and dry sand.


4-20

The Research Laboratory of H. Kramer & Co. in-vestigated many types of test bar designs that were in use in the late 1930’s, hoping that one of the designs could be used for determining the properties of all the various classes of sand cast copper-base alloys. The development of the double horizontal full web test bar came after testing many various designs of vertical and horizontal web and cast-to-shape bars and the keel block. The cast-to-shape bars proved to produce unsound bars when used for the aluminum bronzes and manganese bronzes. The vertical Web-Webbert and the Crown test bar designs were un-wieldly to mold and the gating was such that dross was almost impossible to eliminate from the test section when testing aluminum bronzes and manganese bronzes. The keel block design took an excessive amount of metal for the test bar (and excessive machining costs) and also proved to produce unsound test bars in the tin bronzes and red brasses.

The double horizontal full-web test bar design proved to give maximum soundness and properties for all the various cast copper-base alloys. The design did not require elaborate gating systems and was relatively easy to mold and pour.

In the 1940’s, the Brass and Bronze Ingot Institute sponsored work at Battelle Memorial Institute on the ef-fect of gases in 85-5-5-5 red brass alloy. One phase of the research program was to determine which design of test bar would give the best indication of melt quality or gas content. Eleven various test bar casting designs were in-vestigated and the H. Kramer & Co’s. double horizontal full-web test bar design proved to give the best and most consistent indication of melt quality. (1)

The double horizontal full-web test bar was also used by Battelle Memorial Institute for determining the me-chanical and physical properties of eight cast copper-base alloys: (2, 3, 4, 5).

DEVELOPMENT OF DOUBLE HORIZONTAL FULL-WEB TEST BAR

FIG. 2a Double Horizontal Full-Web Type Test Bars


4-21

ASTM B30 Alloy 922 88-6-2-4 Leaded Tin Bronze

836 85-5-5-5 Red Brass

937 80-10-10 High Lead Tin Bronze

848 76-2½-6½-15 Semi-Red Brass

865 65,000 TS Manganese Bronze

863 110,000 TS Manganese Bronze

976 20% Nickel Silver

875 Silicon Brass (Tombasil)Various government agencies and the American So-

ciety for Testing Materials have indicated that the double horizontal full web test bar design may be used as one of the acceptable methods for test bars for sand cast copper-base alloys. For example, the double horizontal full web test bar is shown as:Fig. 3—ASTM B208—Recommended Practices for Tension Test Specimens for Copper-Base Alloys for Sand Castings

Fig. 9—Federal Test Method Standard No. 151—Metals; Test Methods

1. “Test Bars for 85-5-5-5 Alloy, Their Design and Some Factors Affecting Their Design” by Dr. G. H. Clam-er—A. F. A. Annual Foundation Lecture, 1946

2. “Mechanical and Physical Properties of Three Low Shrinkage, Copper-Base Casting Alloys” by Kura & Lang. ASTM Proceedings Vol. 58, 1958

3. “The Creep Properties of Three Low Shrink-age, Cop-per-Base Casting Alloys” by Simmons & Kura, ASTM Proceedings, Vol. 58, 1958

4. “Mechanical and Physical Properties of Five Copper-Base Casting Alloys” by Johnson & Kura, ASTM Pro-ceedings, Vol. 60, 1960

5. “The Creep and Rupture Properties of Five Copper-Base Casting Alloys” by Moon & Simmons, ASTM Proceedings, Vol. 61, 1961

Kramer 5/8” Web-Webbert horizontal test bar casting.


4-22

Copper or alloyed copper castings are used in the electrical industry for their current-carrying characteristics. Howev-er, sound copper castings, with a minimum of 85 per cent I. A. C. S. electrical conductivity, are difficult to make. The ordinary deoxidizers, such as silicon, aluminum, zinc and phosphorus, cannot be used because residual amounts lower the electrical conductivities drastically.

Cast copper is soft and low in strength. Im-proved mechanical properties with good conductivity (40 to 80 per cent I. A. C. S.) may be obtained with heat-treated alloys containing silicon, cobalt, chromium, nickel and beryllium in various combinations. However, these alloys are expensiveand less readily available than the stan-

dard copper-base foundry alloys, and due to the highly oxidizable nature of their alloying elements (silicon, chro-mium and beryllium), extra care is required in melting and pouring.

In many instances, where design permits the use of lower electrical conductivities, the standard copper-base foundry alloys may be used. Tables I through VIII list the electrical conductivities of the various classes of copper-base casting alloys.

*Data from A.F.S. paper “Electrical Conductivity of Sand Cast Copper-Base Alloys” by F. L. Riddell and D. G. Schmidt—A.F.S. Transactions, 1959.

ELECTRICAL CONDUCTIVITY OF THE CAST COPPER BASE ALLOYS*

Cu Sn Pb Zn Fe Sb Ni P

89-11-0-0 89.0 10.6 trace trace 0.03 trace trace 0.24 9.6

88-10-2-0 87.5 9.3 2.2 0.3 0.02 0.09 0.4 0.02 11.0

88-10-0-2 86.8 10.1 0.2 2.5 0.06 0.03 0.3 0.02 10.9

88-8-0-4 87.6 8.2 0.15 3.8 0.08 0.03 0.1 0.01 12.4

88-6-2-4 88.3 6.0 1.8 3.1 0.08 0.10 0.6 0.01 13.8

88-5-2-5 87.0 5.3 2.2 4.5 0.15 0.03 0.5 0.01 14.1

87-11-1-0-1 (Ni) 87.6 10.2 1.0 0.3 0.01 0.03 0.9 0.01 11.1

87-11-1-0-1 (Ni) 87.0 10.5 1.0 0.3 0.01 0.03 0.9 0.19 10.1

87-11-1-0-1 (Ni) 86.0 10.6 1.1 0.7 0.10 0.03 1.0 0.31 9.2

87-11-0-1-1 (Ni) 85.9 11.5 0.2 1.0 0.03 0.03 1.3 0.01 10.1

87-10-1-2 86.7 9.7 0.9 2.1 0.10 0.10 0.4 0.02 10.8

87-10-2-1 86.4 9.7 1.6 1.6 0.03 0.10 0.5 0.01 11.0

87-8-1-4 87.5 8.0 0.7 3.3 0.15 0.10 0.2 0.02 12.3

88-5-0-2-5 (Ni) 87.1 5.4 0.01 2.4 0.03 0.02 5.1 0.01 11.5

88-5-0-2-5 (Ni) (Cooled in sand to room temp.) 11.9

88-5-0-2-5 (Ni) (H.T. — 1400 F - 4 hr - oil quench + 600 F - 5 hr - air cool) 14.8

87-5-1-2-5 (Ni) 86.5 5.1 1.1 2.1 0.10 0.02 5.0 0.02 12.0

87-5-1-2-5 (Ni) (H.T. — 1400 F - 5 hr - air cool + 600 F - 7 days - air cool) 15.7

85-9-1-0-5 (Ni) 83.6 9.2 1.2 0.4 0.1 0.02 5.2 0.01 10.3

84-16-0-0 83.9 15.4 0.05 0.3 trace 0.02 0.02 0.01 8.5

TABLE 1 — ELECTRICAL CONDUCTIVITY OF SAND-CAST TIN BRONZES AND LEADED TIN BRONZES

Alloy NominalComposition

Composition, per cent Average %I.A.C.S.


4-23

Cu Sn Pb Zn Fe Sb Ni P 87-4-8-1 86.4 4.1 8.0 0.9 0.02 0.15 0.30 0.01 16.485-5-9-1 83.4 4.5 9.8 1.4 0.03 0.20 0.50 0.02 14.984-8-8-0 83.3 7.4 8.1 0.5 0.02 0.20 0.25 0.01 11.884-4-8-4 84.4 4.0 8.3 2.7 0.10 0.10 0.40 0.01 16.983-7-7-3 82.8 6.8 7.5 2.1 0.10 0.15 0.60 0.01 12.481-8-9-0-2 (Ni) 82.2 7.0 9.0 0.2 0.01 0.20 1.25 0.01 12.180-10-10 79.7 8.8 10.1 0.7 0.01 0.20 0.35 0.01 11.078-7-15 77.4 6.8 14.5 0.7 0.03 0.30 0.25 0.02 11.675-3-20-0-2 (Ni) 75.0 3.4 18.4 0.3 0.05 0.15 2.20 0.01 14.275-13-10-0-2 (Ni) 74.8 13.1 9.4 0.5 0.02 0.15 2.00 0.01 8.673-5-22 73.1 4.2 21.9 0.1 0.01 0.05 0.50 0.01 14.166-2-32 66.1 1.9 31.0 0.1 0.01 0.05 0.50 0.01 17.8

TABLE 2 — ELECTRICAL CONDUCTIVITY OF SAND-CAST HIGH LEAD TIN BRONZES



Cu Sn Pb Fe Sb Ni Others 72-1-5-22 72.8 1.6 4.7 0.4 0.2 0.6 18.668-1-3-28 68.1 1.0 2.3 0.3 0.1 0.2 19.664-0-0-35-1 64.5 0.05 0.1 0.1 trace trace 1.1 Si 15.163-1-1-35 61.9 0.6 1.0 0.2 0.05 0.3 22.063-1-1-35 61.8 0.7 1.1 0.2 0.05 0.1 0.25 Al 21.860-1-0-38-1 59.9 1.0 0.04 0.01 0.05 0.3 1.15 Al 23.760-0-3-37 61.5 0.1 2.8 0.10 trace trace 0.06 Al 25.760-0-1-38-1 59.5 trace 1.0 0.30 0.01 0.05 1.1 Al 26.560-0-0-40 60.9 0.05 0.1 0.4 trace 0.05 0.8 Al 24.960-0-2-38 58.7 0.05 2.2 0.1 trace 0.02 26.458-1-1-40 58.6 1.0 0.8 0.5 0.01 0.10 0.5 Al 23.352-0-0-48 52.4 0.1 0.05 0.01 trace trace 0.4 Al 35.8

Cu Sn Pb Zn Fe Sb Ni P93-1-2-4 93.1 0.9 2.5 3.0 0.05 0.05 0.30 0.01 32.485-5-5-5 84.6 4.5 5.3 4.6 0.10 0.15 0.65 0.02 15.083-4-6-7 82.4 3.8 6.4 6.5 0.20 0.20 0.50 0.02 15.283-3-3-11 82.9 3.0 2.9 10.1 0.20 0.15 0.70 0.01 16.781-3-7-9 81.2 2.6 7.2 8.0 0.25 0.15 0.50 0.02 16.680-5-5-5-5 (Ni) 79.9 4.8 5.4 4.6 0.30 0.15 4.80 0.02 11.178-3-7-11-1 (Ni) 79.7 2.6 6.2 10.0 0.25 0.15 1.10 0.01 16.076-3-6-15 74.6 3.2 7.3 14.3 0.15 0.10 0.30 0.01 16.676-2½-6½-15 76.7 2.4 6.5 13.6 0.30 0.10 0.35 0.02 17.776-2-6-16 75.3 2.1 6.9 15.0 0.15 0.10 0.35 0.03 19.076-1-6-17 75.9 1.1 7.6 14.8 0.15 0.10 0.30 0.02 21.3

TABLE 3 — ELECTRICAL CONDUCTIVITY OF SAND-CAST LEADED RED BRASS AND LEADED SEMI-RED BRASS



TABLE 4 — ELECTRICAL CONDUCTIVITY OF SAND-CAST YELLOW BRASS




4-24

Cu Fe Al Mn Ni

Copper-Aluminum

95-5 As-cast 94.8 0.01 5.1 trace 0.03 17.0 90-10 As-cast 88.8 0.10 11.0 0.01 trace 13.6 88-12 As-cast 87.9 0.10 11.8 0.01 0.05 20.3

Copper-Iron-Aluminum 90-1-9 As-cast 89.1 1.5 9.2 0.10 0.10 12.9 89-1-10 As-cast 88.2 1.4 10.1 0.01 0.03 15.1 89-1-10 Heat treated* 88.2 1.4 10.1 0.01 0.03 12.7 88-3-9 As-cast 87.4 3.4 8.9 0.06 0.20 12.2 86-4-10 As-cast 85.9 3.4 10.4 0.06 0.05 14.6 86-4-10 Heat treated* 85.9 3.4 10.4 0.06 0.05 12.4 84-4-12 As-cast 84.4 3.5 11.8 0.05 0.05 16.8 81-5-14 As-cast 80.8 4.8 14.0 0.20 0.05 10.8

Copper-Iron-Aluminum-Nickel 88-1-10-1 As-cast 88.1 0.8 9.9 0.01 1.1 13.4 87-1-10-2 As-cast 87.1 0.9 9.8 0.06 2.1 12.2 84-4-10-2 As-cast 83.4 3.9 10.4 0.1 2.1 11.0 84-4-10-2 Heat treated* 83.4 3.9 10.4 0.1 2.1 10.2 81-3-11-5 As-cast 81.5 2.9 10.5 0.1 4.9 9.4 81-4-11-4 As-cast 81.6 4.0 10.4 0.1 3.8 10.3 80-5-10-5 As-cast 79.5 4.8 10.2 0.1 5.2 8.9 80-5-10-5 Heat treated* 79.5 4.8 10.2 0.1 5.2 8.4 76-5-14-5 As-cast 76.7 4.4 14.0 0.2 4.6 12.6

Copper-Iron-Aluminum-Manganese 85-3-11-1 As-cast 85.3 2.6 10.7 1.1 0.05 10.5 85-3-11-1 Heat treated* 85.3 2.6 10.7 1.1 0.05 9.4

Copper-Iron-Aluminum-Nickel-Manganese 80-5-9-5-1 As-cast 78.9 4.5 9.6 1.4 5.4 6.9 79-5-9-5-2 As-cast 78.9 4.8 9.1 2.1 4.8 6.5 78-5-9-5-3 As-cast 77.3 4.8 9.6 3.2 4.9 5.8

*Heat Treatment — 1650 F (905 C), 2 hr, water quench, plus 1100 F (595 C), 1 hr, water quench.

TABLE 5 — ELECTRICAL CONDUCTIVITY OF SAND-CAST ALUMINUM BRONZES



Condition of Bars


4-25

Cu Sn Pb Zn Fe Ni Others 9% Nickel Silver 50.6 1.4 0.1 35.3 1.1 10.5 1.0 Al 9.412% Nickel-Copper 84.8 0.01 0.01 0.01 0.9 12.0 1.2 Al 10.1 0.7 Mn12% Nickel Silver 64.5 2.6 6.3 14.3 0.6 11.4 6.512% Nickel Silver 54.7 1.9 9.9 19.7 1.2 12.4 5.715% Nickel Silver 63.1 2.2 7.3 10.5 0.5 16.0 5.418% Nickel-Copper-Zinc 64.8 trace trace 8.5 1.0 17.7 8.0 Al 9.320% Nickel Silver 65.0 3.7 3.8 6.0 1.0 20.2 5.020% Nickel-Copper-Zinc 57.6 0.3 0.5 21.0 1.2 19.5 0.25 Al 4.723% Nickel-Copper-Tin 63.6 10.2 0.05 1.8 0.8 23.4 5.625% Nickel Silver 59.5 1.3 2.0 10.9 1.6 24.4 4.225% Nickel Silver 65.7 4.7 0.9 2.8 0.8 25.0 4.628% Nickel-Copper 66.8 trace trace trace 4.3 28.1 0.6 Mn 5.230% Nickel-Copper 68.8 trace trace trace 0.5 29.3 0.7 Mn 4.6 0.7 Si

TABLE 6 — ELECTRICAL CONDUCTIVITY OF SAND-CAST HIGH-STRENGTH YELLOW BRASS (MANGANESE BRONZE)

Alloy Composition, per cent Average %I.A.C.S.

Cu Fe Mn Si Zn Others 96-1-3 95.8 0.15 1.1 3.0 0.1 6.595-1-4 94.7 0.2 1.1 3.8 — 5.995-1-4 95.0 0.1 — 3.7 0.3 0.8 Sn 6.692-4-4 92.0 0.1 — 4.4 3.5 6.191-4-3-1 ½ 90.4 1.2 — 3.2 4.6 0.4 Al 7.491-2-7 90.5 0.1 — 2.2 0.2 7.1 Al 8.886-2-7-5 85.9 0.1 0.02 2.0 4.9 7.0 Al 7.390-4-2-4 90.2 0.2 0.01 1.4 3.6 4.5 Al 10.781-4-15 81.9 0.2 0.01 4.0 13.9 6.5

Cu Fe Al Mn Others60.000 psi T.S. 58.8 0.9 0.7 0.4 0.6 Sn 19.3 0.8 Pb65.000 psi T.S. 58.4 1.0 1.0 0.25 21.9Nickel Manganese Bronze 53.9 1.6 1.3 3.2 3.2 Ni80.000 psi T.S. 58.5 1.6 1.7 1.0 16.790.000 psi T.S. 59.1 1.6 2.2 1.7 14.590.000 psi T.S. 64.0 2.2 3.9 4.0 7.490.000 psi T.S. 58.4 2.0 3.1 0.1 24.090.000 psi T.S. 66.8 2.5 5.4 3.9 7.4110.000 psi T.S. 62.5 2.7 6.0 3.8 7.9

TABLE 7 — ELECTRICAL CONDUCTIVITY OF CAST SILICON BRONZES AND SILICON BRASSES



TABLE 8 — ELECTRICAL CONDUCTIVITY OF SAND-CAST NICKEL SILVERS AND COPPER-NICKEL ALLOYS



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