GB1568091A - High damping capacity alloy - Google Patents

Description

(54) A HIGH DAMPING CAPACITY ALLOY (71) We, ZAIDAN HOJIN:DENKI JIKI ZAIRYO KENKYUSHO, of No.

1-1, 2-Chome, Minami, Yagiyama, Sendai City, Japan, an incorporated foundation organized under the laws of Japan, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- The present invention relates to a high damping capacity alloy having a damping capacity of more than about 2 X 104 over a wide temperature range and more particu marly to a high vibration damping capacity alloy having good cold workability and high corrosion resistance.

Recently, elements or members made of alloys having damping capacities have been widely used in precision instruments susceptible to vibrations, and machines such as aircraft, ships, vehicles and the like which cause vibrations and noise, for the purpose of reducing the public nuisance of such vibrations and noises.

In the prior art, alloys of Mn-Cu, Ni-Ti, Zn-Al, etc. having values of Q-1 of more than 0.005 have been commonly used. The value of t1 indicates the inherent damping capacity of the alloy against vibration and can be defined by the following equation: a Ir where a is logarithmic decrement. In other words, Q is a function of the energy damped during one cycle. The larger the value of Q-l the more energy of the vibration is damped so that the amplitude becomes smaller in a shorter period of time, thus exhibiting a higher damping effect.

Among the damping alloys of the prior art, the alloys of Mn-Cu and Ni-Ti are best in damping capacity characteristics at room temperature. However, as temperature in creases, the damping capacity decreases rapidly and becomes substantially zero at tempera tures near 100"C so that the alloys are hardly distinguishable in damping capacity from normal metals at these temperatures. Such alloys do not exhibit any damping capacity at a temperature higher than 100"C.

On the other hand, alloys of Zn-Al of the prior art have a high damning capacity at temperatures higher than 1000C, but as the temperature is lowered the damping capacity decreases rapidly and becomes very small at room temperature. These alloys of Mn-Cu, Ni-Ti and Zn-Al are poor in cold workability and corrosion resistance.

An object of the present invention is to obviate or mitigate the aforesaid disadvantages.

According to this invention there is pro vided a process for preparing a product having a vibration damping capacity of greater than 2 X 10-S, comprising the steps of: preparing an alloy consisting of from 0.01 to 5% by weight in total of copper and/or molyb denum, the balance being iron, by melting together in a furnace, adding to the molten alloy less than 1% by weight of a deoxidiz ing element, casting the alloy, heat-treating the cast product at a temperature of from 8000C to the melting point of the alloy for a period of from one minute to 100 hours and cooling the product to ambient tempera ture at a rate of from 10 C per second to 20000C per second.

Preferably also the cast product is held at a temperature of from 8000C to the melting point of the alloy for a period of from 5 minutes to 50 hours.

The cooled product may be reheated to a temperature of from 1000C to 1,600"C for a period of from one minute to 100 hours and then cooled at a rate of from 1 0C per second to 10C per hour.

The deoxidizing element may be one or more of manganese, silicon, titanium, aluminium and calcium.

The cast product may be formed into an article by forging, rolling or swaging prior to heat treatment A preferred alloy contains from 0.5 to 1.5% by weight of copper, the balance being iron.

Another preferred alloy contains from 0.1 to 5.0% by weight of molybdenum, more preferably from 0.5 to 1.5% by weight, the balance being iron.

The alloy may also contain from 0.01 to 40% by weight in total of an additional element selected from one or more of the following groups: (a) less than 40% by weight of chromium; (b) less than 10% by weight in total of at least one of aluminium, nickel, man ganese, antimony, niobium, tungsten, titanium, vanadium, and tantalum; (c) less than 5% by weight in total of one or more of silicon, tin, zinc and zir conium; and (d) less than 1% by weight in total of one or more of cobalt, lead and yttrium.

The invention will now be illustrated in more detail with reference to the drawings, in which: Figs. la and ib are graphical representations of the relationship between the composition and damping capacity of, respectively, Fe-Cu and Fe-Mo alloys of the invention under annealed conditions.

Figs. 2a and 2b are graphical representations of the relationship between the composition and damping capacity of, respectively, Fe~1% Cu-Cr and Fe-1 % Mo- Cr alloys used in the invention under annealed conditions; and Figs. 3a and 3b are graphical representations showing the difference between the damping capacity characteristics of the alloys of Fe-Cu, Fe-Cu-Cr (3a), Fe-Mo and Fe-Mo-Cr (3b) used in the invention and Mn-Cu in the prior art at various temperatures.

According to the invention, a starting material consisting of 0.015% by weight of Cu and/or Mo, and the remainder Fe is melted in air or inert gas or in vacuum in a furnace. The starting material may have 0.01----40% in total of at least one additional component selected from less than 40% of Cr, less than 10% of Al, Ni, Mn, Sb, Nb, W, Ti, V and Ta, less than 5% of Si, Sn, Zn, and/or Zr, less than 1% of Co, Pb, and Y. A small amount (less than 1%) of manganese, silicon, titanium, aluminium or calcium is added to the melt to remove undesirable impurities. The melt is then stirred to produce a molten alloy of uniform compositions and cast. The alloy thus produced may be forged, rolled or swaged at room temperature or at a temperature lower than 1,3000C to form a blank, prior to heat treatment.

The cast or formed alloy may be further subjected to the following treatments.

(A) Further cold worked after the above quenching.

(B) After the above quenching or cold working of step (A), the formed article may be heated at a temperature between 1000C and lower than the temperature for the quenching (i.e. 800-1,6000 C) for between one minute and 100 hours, preferably 5 minutes to 50 hours and then cooled at a rate of between 1 C/sec and 1 C/hour.

In the above treatment (B), the time of one minute to 100 hours required for heating the blank depends upon the weight of the blank to be heated, the temperature to which it is heated and the composition thereof. In other words, a material having a high melting point such as 1,6000C may be heated to just below 1,600 C, so that the time for heating at that temperature may be short, for example, 1-5 minutes. On the other hand, when the heating is effected at a temperature near the lower limit of 800"C, a long period of time such as 100 hours is necessary for the heating.

The heating time may vary greatly depending on the wide range of the material, weight or massiveness from 1 gram, as in a laboratory scale, to 1 ton as in a factory scale. For comparison, at the same temperature, a small size of material only requires 1 minute to 5 hours for the solution treatment, while a large bully of material requires 10--100 hours for the treatment.

If the solution treatment is incomplete, the tensile strength and damping capacity of the article is considerably reduced and also the production yield is poor.

In the cold working of the step (A), the tensile strength is improved, but the damping capacity is somewhat reduced due to the presence of residual strain. However, if the working ratio is sufficiently small, the residual strain introduced is not great, so that the tensile strength can be increased without noticeably lowering the damping capacity.

On the other hand, if the working ratio is large, the worked article is subjected to a heat treatment in the subsequent step (B), whereby a homogeneous stable structure is obtained, so that the damping capacity is substantially restored to the initial value.

The invention will be explained with reference to an example.

Mixtures of total weight of about 500 grams having the composition of Fe and Cu as shown in Table 1 were melted in an alumina crucible in a high-frequency induction furnace in an atmosphere of argon gas.

After stirring, each melt was poured into a mold to obtain an ingot having a square section of 35 X 35 mm. The ingots were then forged into rods having a 10 mm diameter circular section. The rods were annealed at 1,000cC for one hour and quenched. Then the rods were drawn at room temperature to form wires of 0.5 mm diameter which were then cut into a plurality of wires having suitable lengths. Some of the wires were heated at 1,000"C for one hour and cooled at a rate of 1000C per hour to provide test pieces for measuring the damping capacity by the torsion pendulum method and for measuring the tensile strength. Table 1 illustrates the results of the tests. The products prepared according to the invention have a remarkably higher damping capacity (higher by the factor of several tens) than that Q-1 = 0.1 (X 1F5) of the conventional steel containing 0.1% carbon.

TABLE TABLE 1

Damping capacity Q-l (x 10-3) Tensile sltrgen$, Composition 0 C | 50 C | 100 C | 200 C 300 C 4000C 200C Annealed condition by cooling at a rate of 1000C;'hr Fe(%) Cu(%) after heated at 1,000 C for one hour 99.5 0.5 10.7 10.7 10.7 10.8 10.8 10.9 37 99.0 1.0 11.8 11.8 11.8 11.8 11.9 12.0 38 96 % cold worked condition after annealed 99.5 0.5 7.3 7.3 7.3 7.3 7.4 7.7 40 99.0 1.0 8.5 8.5 8.5 8.5 8.5 8.9 41 Water quenched condition after heated at l,0005C for one hour 99.5 0.5 8.4 8.4 8.4 8.5 8.5 8.5 45 99.0 1.0 9.5 9.5 9.6 9.6 9.7 9.8 46 Tables 2-9 show the damping capacities and tensile strengths of typical alloys according to the invention.

TABLE 2

Damping capacity Q-l ( > c 10-3) Tensile strength Composition 0 C 500C 1000C 2000C 3000C 4000C Kg/mm 20 C Added Fe Cu elements Annealed condition by cooling at a rate of 100 C/hr (%) (%) (%) after heated at 1,0000C for one hour 84.0 1.0 Cr 15.0 19.3 19.3 19.4 19.4 19.4 19.5 55 94.0 1.0 Al 5.0 15.6 15.6 15.6 15.7 15.8 15.9 40 94.0 1.0 Ni 5.0 9.5 9.5 9.5 9.6 9.6 9.7 48 94.0 1.0 Mn 5.0 6.5 6.5 6.5 6.5 6.5 6.8 43 94.0 1.0 Sb 5.0 5.7 5.7 5.7 5.7 5.7 5.8 40 94.0 1.0 Nb 5.0 4.5 4.5 4.5 4.6 4.7 4.8 50 94.0 1.0 Mo 5.0 12.5 12.5 12.6 12.6 12.7 12.8 54 94.0 1.0 W 5.0 10.5 10.5 10.5 10.5 10.6 10.6 55 94.0 1.0 Ti 5.0 7.5 7.5 7.5 7.5 7.8 7.9 57 94.0 1.0 V 5.0 8.5 8.5 8.5 8.5 8.6 8.8 60 94.0 1.0 Ta 5.0 5.4 5.5 5.5 5.5 5.6 5.7 55 96.5 1.0 Si 2.5 4.3 4.3 4.3 4.3 4.4 4.5 50 96.5 1.0 Sn 2.5 6.6 6.6 6.6 6.7 6.7 6.8 45 96.5 1.0 Zn 2.5 5.8 5.8 5.8 5.8 5.8 5.9 40 96.5 1.0 Zr 2.5 4.8 4.8 4.8 4.8 4.9 4.9 45 98.5 1.0 Co 0.5 6.8 6.8 6.8 6.8 6.8 6.9 40 98.5 1.0 Pb 0.5 5.9 5.9 5.9 5.9 5.9 5.9 40 98.5 1.0 Y 0.5 6.6 6.6 6.7 6.8 6.8 6.8 53 TABLE 3

Damping capacity Q-' (x 10-3) Tensile strength2 Composition Kg/mm /mm OOC 00C 500C 1000C 2000C 3000C 4000C 200C Added Fe Cu elements 96% cold worked condition after annealed (%) (%) (%) 84.0 1.0 Cr 15.0 7.5 7.5 7.5 7.5 7.6 7.7 65 94.0 1.0 Al 5.0 6.6 6.6 6.6 6.7 6.7 6.8 51 94.0 1.0 Ni 5.0 5.4 5.4 5.4 5.4 5.4 5.5 58 94.0 1.0 Mn 5.0 3.7 3.7 3.7 3.7 3.7 3.8 55 94.0 1.0 Sb 5.0 4.1 4.1 4.1 4.1 4.2 4.3 50 94.0 1.0 Nb 5.0 3.1 3.1 3.1 3.1 3.1 3.1 62 94.0 1.0 Mo 5.0 7.5 7.5 7.5 7.5 7.5 7.6 63 94.0 1.0 W 5.0 4.4 4.4 4.4 4.5 4.5 4.6 66 94.0 1.0 Ti 5.0 5.5 5.5 5.5 5.6 5.6 5.6 68 94.0 1.0 V 5.0 4.2 4.2 4.2 4.2 4.3 4.3 70 94.0 1.0 Ta 5.0 3.8 3.8 3.8 3.8 3.8 3.9 66 96.5 1.0 Si 2.5 3.0 3.0 3.0 3.0 3.0 3.2 62 96.5 1.0 Sn 2.5 4.7 4.7 4.7 4.7 4.7 4.7 54 96.5 1.0 Zn 2.5 4.4 4.4 4.4 4.5 4.5 4.6 53 96.5 - 1.0 Zr 2.5 3.5 3.5 3.5 3.5 3.5 3.6 56 98.5 1.0 Co 0.5 6.0 6.0 6.0 6.1 6.2 6.3 52 98.5 1.0 Pb 0.5 4.5 4.5 4.5 4.5 4.6 4.7 50 98.5 1.0 Y 0.5 5.0 5.0 5.0 5.0 5.0 5.0 60 TABLE 4

Damping capacity Q-1 ( x 10-3) Tensile strength Composition mm OOC 00C 500C 1000C 2000C 3000C 400 C 20 C Added Fe Cu elements Water quenched condition after heated at 1.000 C (%) (% (%) for one hour 84.0 1.0 Al 5.0 7.9 7.9 7.9 7.9 8.0 8.0 44 94.0 1.0 Ni 5.0 6.5 6.5 6.5 6.5 6.5 6.6 53 94.0 1.0 Mn 5.0 4.3 4.3 4.3 4.4 4.4 4.5 48 94.0 1.0 Sb 5.0 4.2 4.2 4.2 4.2 4.2 4.3 46 94.0 1.0 Nb 5.0 3.6 3.6 3.6 3.7 3.7 3.8 53 94.0 1.0 Mo 5.0 8.5 8.5 8.5 8.5 8.6 8.6 59 94.0 1.0 W 5.0 5.5 5.5 5.6 5.6 5.6 5.7 60 94.0 1.0 Ti 5.0 6.6 6.6 6.6 6.6 6.7 6.8 61 94.0 1.0 V 5.0 5.5 5.5 5.5 5.6 5.7 5.8 64 94.0 1.0 Ta 5.0 4.4 4.4 4.4 4.5 4.6 4.7 60 96.5 1.0 Si 2.5 3.3 3.3 3.3 3.4 3.5 3.6 54 96.5 1.0 Sn 2.5 5.8 5.8 5.8 5.9 5.9 6.0 50 96.5 1.0 Zn 2.5 5.0 5.0 5.0 5.0 5.1 5.2 45 96.5 1.0 Zr 2.5 3.7 3.7 3.7 3.8 3.8 3.9 49 98.5 1.0 Co 0.5 6.1 6.1 6.1 6.1 6.2 6.3 48 98.5 1.0 Pb 0.5 4.8 4.8 4.8 4.8 4.9 4.9 44 98.5 1.0 Y 0.5 5.5 5.6 5.6 5.6 5.6 5.7 58 TABLE 5

Damping capacity Q-l (x 10-3) Tensile strength Composition 00C 500C 1000C 2000C 300 4000C 200C Annealed condition by cooling at a rate of 1000C/hr Fe(%) Mo ( ic) after heated at 1,0000C for one hour 99.0 1.0 6.7 6.7 6.7 6.7 6.7 6.9 42 98.0 2.0 4.2 4.2 4.2 4.2 4.3 4.6 44 96% cold worked condition after annealed 99.0 1.0 5.0 5.0 5.0 5.0 5.0 5.4 50 98.0 2.0 3.2 3.2 3.2 3.2 3.4 3.8 52 Water quenched condition after heated at 1,0000C for one hour 99.0 1.0 5.5 5.5 5.5 5.5 5.6 5.9 48 98.0 2.0 3.9 3.9 3.9 3.9 3.9 4.0 49 TABLE 6

Damping capacity Q-1 (x 10-3) Tensile strength Kg,mm Composition Ooc sooc ioooc 100 C 3000C 4000C 200C Added Fe Mo elements Annealed condition by cooling at a rate of 1000C/hr (%) (No) (%) after heated at 1,0000C for one hour 84.0 1.0 Cr 15.0 30.0 30.0 30.0 30.0 30.1 31.3 51 94.0 1.0 Al 5.0 15.4 15.4 15.4 15.4 16.0 16.3 45 94.0 1.0 Ni 5.0 8.5 8.5 8.5 8.5 8.7 8.8 49 94.0 1.0 Mn 5.0 7.4 7.4 7.4 7.5 7.6 7.8 45 94.0 1.0 Sb 5.0 9.4 9.5 9.6 9.7 9.8 9.9 44 94.0 1.0 Nb 5.0 8.3 8.4 8.4 8.4 8.5 8.7 50 94.0 1.0 W 5.0 6.6 6.6 6.6 6.6 6.6 6.8 50 94.0 1.0 Ti 5.0 8.4 8.5 8.5 8.5 8.6 8.7 50 94.0 1.0 V 5.0 9.2 9.2 9.2 9.2 9.3 9.4 49 94.0 1.0 Ta 5.0 8.7 8.7 8.8 8.9 9.0 9.2 47 96.5 1.0 Si 2.5 5.3 5.3 5.3 5.3 5.4 5.5 46 96.5 1.0 Sn 2.5 7.6 7.6 7.6 7.6 7.6 7.6 45 96.5 1.0 Zn 2.5 6.4 6.4 6.4 6.4 6.5 6.7 41 96.5 1.0 Zr 2.5 8.3 8.3 8.3 8.3 8.3 8.4 44 98.5 1.0 Co 0.5 9.4 9.5 9.6 9.6 9.7 9.8 45 98.5 1.0 Pb 0.5 8.6 8.6 8.8 8.9 9.0 9.2 40 98.5 1.0 Y 0.5 8.7 8.8 8.9 9.0 9.0 9.5 52 TABLE 7

Damping capacity Q-1 (x 10-3) Tensile Composition 0 C 500C 1000C 2000C 3000C 4000C strength Added Fe Mo elements 96% cold worked condition after annealed 94.0 1.0 Al 5.0 8.6 8.6 8.6 8.6 8.7 8.8 66.0 94.0 1.0 Ni 5.0 6.5 6.5 6.5 6.6 6.7 6.8 68.0 94.0 1.0 Mn 5.0 4.3 4.3 4.3 4.3 4.4 4.5 65.0 94.0 1.0 Sb 5.0 5.6 5.7 5.6 5.6 5.6 5.6 63.2 94.0 1.0 Nb 5.0 4.4 4.4 4.4 4.4 4.5 4.6 71.3 94.0 1.0 W 5.0 4.0 4.0 4.0 4.0 4.1 4.2 70.1 94.0 1.0 Ti 5.0 5.3 5.3 5.3 5.3 5.3 5.3 70.2 94.0 1.0 V 5.0 6.1 6.1 6.1 6.1 6.1 6.1 68.5 94.0 1.0 Ta 5.0 5.5 5.5 5.5 5.5 5.5 5.6 67.5 96.5 1.0 Si 2.5 4.1 4.1 4.1 4.1 4.1 4.1 65.0 96.5 1.0 Sn 2.5 5.6 5.6 5.6 5.6 5.6 5.6 66.4 96.5 1.0 Zn 2.5 4.0 4.0 4.0 4.0 4.0 4.2 61.5 96.5 1.0 Zr 2.5 5.3 5.3 5.3 5.3 5.3 5.3 63.0 98.5 1.0 Co 0.5 7.2 7.2 7.2 7.2 7.2 7.2 65.6 98.5 1.0 Pb 0.5 6.1 6.1 6.1 6.1 6.2 6.4 60.0 98.5 1.0 Y 0.5 6.5 6.5 6.5 6.5 6.6 6.7 72.0 TABLE 8

Damping capacity Q-1 (x 10-3) Tensile strength Composition Kg;mm2 Added Composition Water sooc 100 C 200 C 300 C 400 C 20OC Added Fe Mo elements Water quenched condition after heated at 1,000 C 94.0 1.0 Al 5.0 10.2 10.2 10.2 10.2 10. 10.2 51.2 94.0 1.0 Ni 5.0 7.6 7.6 7.6 7.6 7.6 7.6 54.4 94.0 1.0 Mn 5.0 6.3 6.3 6.3 6.3 6.3 6.5 51.6 94.0 1.0 Sb 5.0 6.6 6.6 6.6 6.6 6.6 6.7 50.0 94.0 1.0 Nb 5.0 5.4 5.4 5.4 5.4 5.4 5.6 55.0 94.0 1.0 W 5.0 4.8 4.8 4.8 4.8 4.9 5.0 56.0 94.0 1.0 Ti 5.0 6.3 6.4 6.5 6.6 6.7 6.8 56.0 94.0 1.0 V 5.0 7.2 7.2 7.2 7.2 7.3 7.4 53.2 94.0 1.0 Ta 5.0 5.9 5.9 5.9 5.9 5.9 6.0 54.8 96.5 1.0 Si 2.5 4.3 4.3 4.3 4.3 4.4 4.5 52.2 96.5 1.0 Sn 2.5 6.6 6.6 6.6 6.7 6.8 6.8 50.7 96.5 1.0 Zn 2.5 4.3 4.3 4.3 4.3 4.3 4.4 46.6 96.5 1.0 Zr 2.5 6.4 6.4 6.4 6.4 6.4 6.5 50.0 98.5 1.0 Co 0.5 8.1 8.1 8.1 8.1 8.4 8.5 53.3 98.5 1.0 Pb 0.5 6.9 6.9 6.9 6.9 6.9 7.0 44.4 98.5 1.0 Y 0.5 7.7 7.7 7.7 7.8 7.9 8.0 57.0 TABLE 9

Damping capacity Q-1 (x 100-3) Tensile strength Composition 0 C 50 C 100 C 200 C 300 C 400 C Kg/mm I I I, I 50 C 100 C 200 C 300 C 400 C 20 C Added Annealed condition by cooling at a Fe Cu Mo elements rate of 1000C /hr after heated at (%) (%) (%) (%) 1, 0000C for one hour 98.7 0.3 1.0 10.5 10.5 10.5 10.7 11.0 11.8 43.6 96.0 1.0 3.0 - TABLE 9 (Continued)

Damping capacity Q-' (x 100-3) Tensile strength Composition 0 C 50 C 100 C 200 C 3000C 4000C Kg mm2 Added Annealed condition by cooling at a Fe Cu Mo elements rate of 1000C hr after heated at (tic) (C) (%) (%) 1,0000C for one hour 83.0 1.0 - Cr 15.0 Si 1.0 30.7 30.7 30.7 31.0 31.7 33.0 50.8 82.0 1.0 - Cr 15.0 Ti 2.0 26.0 26.0 26.0 26.4 27.0 28.0 51.4 81.0 - 1.0 Cr 15.0 Al 3.0 30.3 30.3 30.3 30.5 31.0 32.2 54.3 81.0 - 1.0 Cr 15.0 W 3.0 31.5 31.5 31.5 31.5 32.7 34.0 53.1 82.0 - 1.0 Cr 15.0 Ti 2.0 39.7 29.7 29.7 29.3 30.4 31.2 51.3 81.0 - 3.0 Cr 15.0 Co 1.0 33.0 33.0 33.0 33.4 34.0 35.0 50.6 82.5 - 3.0 Cr 15.0 Pb 0.5 32.4 32.4 32.4 32.4 33.0 34.0 50.8 As seen from the Figures, the damping capacity of the alloys of the invention is very high at room and high temperature compared with the Mn-Cu alloy. There is a tendency for the alloys of the invention to increase their modulus of elasticity and tensile strength with the increase in the amount of the additional components.

As can be seen from the above description, the alloys of the invention can be effectively used as damping alloy elements for precision instruments susceptible to vibrations in the machines such as aircraft, ships, vehicles, and the like causing vibrations and noises.

The reason for the limitation of composition of the alloy according to the invention is as follows.

The copper and/or molybdenum are limited to 0.01-5% and iron to the remainder in the binary alloy because the damping capacity of higher than 2 X 10-S aimed in the invention could not be obtained by alloys deviating from the limitation of the copper and/or molybdenum and iron.

when the amount of copper and/or molybdenum is less than 0.01%, the damping capacity is not substantially improved compared with alloys of the prior art, while when the amount is more than 5%, the damping capacity decreases. In order to provide an optimum damping capacity, the amount of copper and/or molybdenum is preferably within a range of 0.5-1.5%.

The high damping capacity aimed in the present invention can be accomplished by replacing a part of the copper and/or molybdenum and iron of the binary or ternary alloy with a total of from 0.01 to 40% with any one or more of Cr, Al, Ni, Mn, Sb, Nb, W, Ti, V, Ta, Si, Sn, Zn, Zr, Co, Pb and Y.

Among the additional components, the addition of the element selected from Cr, W, Ti, V, Si, Sn, Zn, Zr, Co and Pb particularly improves the damping capacity of the Fe-Cu and Fe-Mo binary alloys. Furthermore, the addition of the element selected from Cr, Ni, Mn, Nb, W, Ti, V, Ta, Si, Zr and Y especially improves the tensile strength of the Fe-Cu and Fe-Mo binary alloys.

In the ternary alloys of Fe-Cu-Cr, Fe-Mo-Cr, Fe-Cu-Ni, Fe-Mo-Ni, Fe-Cu-W, Fe-Mo-W, Fe-Cu-Ti, Fe-Mo-Ti, Fe-Cu-V, Fe-Mo-V, Fe-Cu-Ta, Fe-Mo-Ta, Fe-Cu-Si, Fe-Mo-Si, Fe-Cu-Sn, Fe-Mo-Sn, Fe-Cu-Zn, Fe-Mo-Zn, Fe-Cu-Zr and Fe-Mo-Zr according to the invention, Cr is limited to less than 40%, Ni, W, Ti, V or Ta to less than 10%, and Si, Sn, Zn, or Zr to less than 5% because alloys deviating from the above limitation does not give the damping capacity of higher than 2 X 10-S required in the invention and does not exhibit good cold workability.

Moreover, in the ternary alloys of Fe Cu-Al, Fe-Mo-Al, Fe-Cu-Mn, Fe Mo-Mn, Fe-Cu-Sb, Fe-Mo-Sb, Fe Cu-Nb, Fe-Mo-Nb, Fe-Cu-Co, Fe Mo-Co, Fe-Cu-Pb, Fe-Mo-Pb, Fe Cu-V and Fe-Mo-Y according to the invention, Al, Mn, Sb or Nb is limited to less than 10% and Co., Pb, or Y is less than 1)c, because alloys deviating from the above limitation do not give the damping capacity of higher than 2 X 10 t required in the present inven- tion and the desired corrosion resistance.

WHAT WE CLAIM IS: 1. A process for preparing a product having a vibration damping capacity of greater than 2 X los, comprising the steps of preparing an alloy consisting of from 0.01 to 5% by weight in total of copper and/or molybdenum, the balance being iron, by melting together in a furnace, adding to the molten alloy less than 1% by weight of a deoxidizing element, casting the alloy, heat-treating the cast product at a temperature of from 800"C to the melting point of the alloy for a period of from one minute to 100 hours and cooling the product to ambient temperature at a rate of from 1 C per second to 20000C per second.

2. A process according to claim 1, in which the cast product is held at a temperature of from 8000C to the melting point of the alloy for a period of from five minutes to 50 hours.

3. A process according to claim 1 or 2, in which the cooled product is reheated to a aemperature of from 100"C to 1,6000C for a period of from one minute to 100 hours and then cooled at a rate of from 1 C per second to 10C per hour.

4. A process according to any preceding claim in which the deoxidizing element is one or more of manganese, silicon, titanium, aluminium and calcium.

5. A process according to any preceding claim in which the cast product is formed into an article by forging, rolling or swaging at a temperature of from ambient to 1300"C prior to heat treatment.

6. A process according to any preceding claim, in which the alloy contains from 0.5 to 1.5% by weight of copper, the balance being iron.

7. A process according to any one of claims 1 to 6 in which the alloy contains from 0.1 to 5.0% by weight of molybdenum, the balance being iron.

8. A process according to claim 7 in which the molybdenum is from 0.5 to 1.5% by weight 9. A process according to any preceding claim, in which the alloy contains also from 0.01 to 40% by weight in total of an additional element selected from one or more of the following groups: (a) less than 40% by weight of chromium; (b) less than 10% by weight in total of at least one of aluminium, nickel, manganese, antimony, niobium, tungs ten, titanium, vanadium and tantalum; (c) less than 5% by weight in total of one or more of silicon, tin, zinc and zir conium; and (d) less than 1% by weight in total of one or more of cobalt, lead and yttrium.

10. A process for producing a product having a vibration damping capacity of greater than 2 X 10-s, according to claim 1 substantially as hereinbefore described.

11. A product having a vibration damping capacity of greater than 2 X 10, whenever produced by the process claimed in any one of the preceding claims.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (11)

**WARNING** start of CLMS field may overlap end of DESC **. because alloys deviating from the above limitation do not give the damping capacity of higher than 2 X 10 t required in the present inven- tion and the desired corrosion resistance. WHAT WE CLAIM IS:

1. A process for preparing a product having a vibration damping capacity of greater than 2 X los, comprising the steps of preparing an alloy consisting of from 0.01 to 5% by weight in total of copper and/or molybdenum, the balance being iron, by melting together in a furnace, adding to the molten alloy less than 1% by weight of a deoxidizing element, casting the alloy, heat-treating the cast product at a temperature of from 800"C to the melting point of the alloy for a period of from one minute to 100 hours and cooling the product to ambient temperature at a rate of from 1 C per second to 20000C per second.

2. A process according to claim 1, in which the cast product is held at a temperature of from 8000C to the melting point of the alloy for a period of from five minutes to 50 hours.

3. A process according to claim 1 or 2, in which the cooled product is reheated to a aemperature of from 100"C to 1,6000C for a period of from one minute to 100 hours and then cooled at a rate of from 1 C per second to 10C per hour.

4. A process according to any preceding claim in which the deoxidizing element is one or more of manganese, silicon, titanium, aluminium and calcium.

5. A process according to any preceding claim in which the cast product is formed into an article by forging, rolling or swaging at a temperature of from ambient to 1300"C prior to heat treatment.

6. A process according to any preceding claim, in which the alloy contains from 0.5 to 1.5% by weight of copper, the balance being iron.

7. A process according to any one of claims 1 to 6 in which the alloy contains from 0.1 to 5.0% by weight of molybdenum, the balance being iron.

8. A process according to claim 7 in which the molybdenum is from 0.5 to 1.5% by weight

9. A process according to any preceding claim, in which the alloy contains also from 0.01 to 40% by weight in total of an additional element selected from one or more of the following groups: (a) less than 40% by weight of chromium; (b) less than 10% by weight in total of at least one of aluminium, nickel, manganese, antimony, niobium, tungs ten, titanium, vanadium and tantalum; (c) less than 5% by weight in total of one or more of silicon, tin, zinc and zir conium; and (d) less than 1% by weight in total of one or more of cobalt, lead and yttrium.

10. A process for producing a product having a vibration damping capacity of greater than 2 X 10-s, according to claim 1 substantially as hereinbefore described.

11. A product having a vibration damping capacity of greater than 2 X 10, whenever produced by the process claimed in any one of the preceding claims.