US3830644A

US3830644A - Copper alloy for plastic-working molds

Info

Publication number: US3830644A
Application number: US00240571A
Authority: US
Inventors: S Watanabe; M Maeda; M Yamaguchi
Original assignee: Hitachi Zosen Corp
Current assignee: Hitachi Zosen Corp
Priority date: 1969-09-19
Filing date: 1972-04-03
Publication date: 1974-08-20
Anticipated expiration: 1991-08-20

Abstract

Copper alloy for plastic-working molds, containing as other principal components aluminum, beryllium, silicon and cobalt, having a value of 9 to 18 weight percent, calculated by an aluminum conversion formula Al + 1.8 percent Be + 1.5 percent Si and 1.5 percent Co, all in weight percent, and containing 6 to 15 percent Al, 0.6 to 2 percent Be, 0.9 to 3.5 percent Si, 0.5 to 2.5 percent Co and the balance Cu, the alloy being characterized by readiness to be used in the as-cast state without being subjected to heat treatment, and having excellent wear resistance under load, as well as high toughness and other desirable mechanical properties. In some cases, the alloy may additionally contain as secondary elements at least one of the elements Sn, Zn, Mn, Fe and Zr. The alloys are particularly suitable for dies in deep drawing, which are required to have high mechanical strength and wear resistance.

Description

United States Patent Watanabe et al.

1 1 Aug. 20, 1974 COPPER ALLOY FOR PLASTIC-WORKING MOLDS [75] Inventors: Seizo Watanabe, Kadoma; Minoru Maeda, Osaka; Masaru Yamaguchi, Nishinomiya, all of Japan [73] Assignee: Hitachi Shipbuilding and Engineering Co., Ltd., Osaka City, Japan [22] Filed: Apr. 3, 1972 [21] Appl. No.: 240,571

Related US. Application Data [63] Continuation-in-part of Ser. No. 859,341, Sept. 19,

1969, abandoned.

[52] US. Cl 75/153, 75/154, 75/157.5, 75/ 162 [51] Int. Cl. C22c 9/10 [58] Field of Search 75/153, 157.5, 160, 154, 75/156, 156.5, 157, 157.5, 162; 148/32 [56] References Cited UNITED STATES PATENTS 1,920,699 8/1933 Hurley 1,957,214 5/1934 Horstkotte.. 1,959,154 5/1934 Bremer 2,400,566 5/1946 Misfeldt 75/159 3,201,234 8/1965 Scherbner et a1 75/157.5 3,459,544 8/1969 Watanabe 75/162 FOREIGN PATENTS OR APPLICATIONS Primary Examiner-Charles N. Lovell Attorney, Agent, or Firm-Tab T. Thein [5 7] ABSTRACT Copper alloy for plastic-working molds, containing as other principal components aluminum, beryllium, silicon and cobalt, having a value of 9 to 18 weight percent, calculated by an aluminum conversion formula Al 1.8 percent Be 1.5 percent Si and 1.5 percent Co, all in weight percent, and containing 6 to 15 percent A1, 0.6 to 2 percent Be, 0.9 to 3.5 percent Si, 0.5 to 2.5 percent Co and the balance Cu, the alloy being characterized by readiness to be used in the as-cast state without being subjected to heat treatment, and having excellent wear resistance under load, as well as high toughness and other desirable mechanical properties. In some cases, the alloy may additionally contain as secondary elements at least one of the elements Sn, Zn, Mn, Fe and Zr. The alloys are particularly suitable for dies in deep drawing, which are required to have high mechanical strength and wear resistance.

6 Claims, 4 Drawing Figures PATENTEBMIBZOW 3.830.644

' SHEET 2N7 2 FIG. 2

TENSILE STRENGTH CONTENT 0F COBALT (Wm) FIG. 3

COPPER ALLOY FOR PLASTIC-WORKING MOLDS This is a continuation-in-part application of application Ser. No. 859,341, filed Sept. 19, 1969, now abandoned, which was titled Copper Base Alloys.

There are a number of hyper-eutectoid copperaluminum base alloys (aluminum bronze) which have been developed and proposed as wear-resistant materials.

In some of them a small amount of iron is added to improve the hardness, and in others a small amount of nickel, manganese, vanadium, etc. is added to improve other mechanical properties.

The present invention relates to a highly wearresistant aluminum bronze of the precipitationhardening type which, unlike the above-mentioned conventional aluminum-bronze materials, is prepared by adding aluminum to the copper base and a small amount of beryllium, silicon and cobalt, as more fully described hereinbelow.

The alloy of the present invention is further characterized in that the aluminum content can be decreased to a relatively low value in the hypo-eutectoid region without sacrificing the excellent wear resistance, therby achieving relatively high elongation.

Adding cobalt to Cu-Be alloys is already known, but from the metallurgical point of view, the cobalt addition in the alloy of the present invention is completely different from that in case of Cu-Be alloys as formerly employed. For further explanation of the metallurgical details, it may be mentioned that Cu-Be alloys are of .aging type in which the added cobalt is effective in regulating the boundary precipitation of Be in the aging well as their weakened eutectoid structures. In order to utilize the y -phase, it is necessary to refine and nodulate the 'y -phase and to regulate the eutectoid transformation.

These effects are obtainable by the aid of the above mentioned Be, Si and Co addition. As a result of a series of our experiments concerning the wear resistance of Cu-Al alloys, it has been clarified that such a metallurgical structure as [50 to 70 percent fine nodular 'y balance [3 acicular a eutectoid (a 'y)] is most outstanding. On the other hand, in CU-Al binary alloys, the balance metallurgical structure, which is obtained by such an Al-quantity as will precipitate a 50 to 70 percent 7 structure, is a coarse (a 'y) structure which cannot be practically utilized.

The alloy of the present invention is characterized in that the additional elements are added so as to change their metallurgical structures from a structure as [coarse -y coarse (a 'y)] to said excellent structure consisting of [50 to 70 percent fine nodular 'y balance [3 ac icular a eutectoid (a y)] in the as-cast state. Consequently, the alloy of the present invention is further characterized in that the y-phase can be utilized even in a case when Cu-Al binary alloys have hypoeutectoid compositions.

As to the effect of each of the additional elements, the following explanation will further contribute to a clearer understanding.

Beryllium is added to regulate a transformation speed A of the eutectoid (a +7) phase, to leave a portion of the B-phase, and to aciculate an a-phase.

Co and Siar e added in order to refine and to nodulate a coarse 'y-phase. The simultaneous addition of Co process However, in the as cast state this effect of and Si is intendedfor their mutual intensifying effect. addition is never noticeable for the Cu Be allow Moreover,Co-add1t1on strengthens the a-phase and the Contrary thereto, the alloy according to the present invention is characterized in that it can be practically The following list shows the change of nodulated used in the as-cast state, such as for plastic-working rates due to the addition of Co or Si alone, or both Co v molds, and in this respect it is an improvement over the 40 and SI together.

Content Weight Cu Al Be Si Co Nodulated Al equivalent rate of v-p A 87.8 9 0.8 2.4 about 43 about 14 B 88.3 7.6 0.8 3.3 about 35 about 14 c 87.91 8.2 0.79 2.3 0.8 about 95 about 14.3

Note: Nodulated Rate J {total of i 'y-phase conventional high-hardness copper base alloys which are necessarily heat-treated before practical use. The Co-addition in the alloy of the present invention relates to the precipitation behavior of the (Cu-Al) 'y -phase and does not relate to the precipitation behavior of Be. Therefore the Co-addition in the present invention must be considered to be completely novel as regards metallurgical conditions.

As seen from the above, the combined use of Si and Co leads to a far better result in the nodulated rate of the y-phase.

Copper base alloys containing as additives Be and Co are disclosed in US. Pat. No. 3,201,234, dated Aug. I7, 1965, to P. J. Scherbner et al., titled Alloy and Method of Producing the Same. However the alloys described in the patent differ essentially from that of the present invention. In the alloys of the patent, titanium is a further additive of prime importance. The range of Ti present in the alloys is 0.02 to 0.2 and Co is in the range of 0.1 to 5 percent, that is, in an amount effective to react with the titanium to form at least one of the compounds TiCo, Ti Co and TiCo As explained in the patent the intermetallic compounds are present as nuclei of the grains of the alloy and the grain structure thus resulting is of materially greater fineness. Contrary tothe addition of Ti and the formation of TiCo intermetallic compounds, the present invention uses Co and Si as addition. Co itself, that is to say, without any other additive, effects the refining of the y phase (primarily precipitated), but the effect The adjustment of the components permits a variatron of the hardness in a range from the hardness of the conventional nickel-aluminum bronze to about 400 H 1s enhanced by the s1multaneous addltion of Co and S1. 5 Preferred Embodiments of the Invention For reasons set forth above the present alloy is partics me xamples of the present copper alloys are ularly well suited for use as material for dies and rolls Shown in Table 2 percentages y g in deep drawing, bending and rolling of such materials I V as stainless steel, mild steel, nickel alloys, zinc alloys, TABLE 2 aluminum alloys, plastics and others.

COMPOSITION OF THE ALLOYS ACCORDING TO A1 B6 5i C0 Cu Hardness THE INVENTION The resent alloy is co er base allo containin as l L3 BHN other p i'incipal componeiiti aluminum, beryllium,iili- 2 8 335 BHN con and cobalt. Permissible limits of the amounts of these components are given below 1n Table 1. In some AS mentioned above beryllium, Silicon and Cobalt cases some other elements may present as secon' are characteristic components of the present copper dary.components as further explamed below v alloy. These elements decrease the a-phase region in It is a feature common to each element that it accelth 1 t d a l rat the rate of erates the precipitation of 7 in a Cu-Al alloy. When the e p f i syshem an cce e 6 effect of aluminum for Promoting Ya-Precipitation in a preclplt'fmon 0 t e CwA] alloy is assumed to be unity the effect of beryh Beryllium changes the ame lar eutectoid structure to lium is 1.8 times that of aluminum, that of silicon 1.5 ac'cular Structure and render? the structure finer times, and the effect of cobalt L5 times For example, S1l1con and cobalt render the matrix structure finer and the figures 1, 1.8, L5 and 1.5 are Called aluminum also cause prec1p1tates to form 1n spherical shape and equivalent. Consequently 'y -precipitation can be exm finer, gram Slze- These ekmems are capable of pressed as the sum of aluminum equivalents of the P P reslstance of the alloys components or, in other words, as the formula for alucordmg to h l i m' minum conversion. The conversion formula is The permlsslble llmlts of the Components are as shown in Table 1. With an aluminum content of less A] 13% Be 15% 15% C0 (all m Welght than 6 percent, no precipitates are observed; if, on the other hand, the Alcontent exceeds 15 percent, precipiand it should be understood as an experimentally detertateS are g atly increased in number a beCOme mined formula which aims to calculate the 'y coarser, thereby causing marked decrease in the precipitation of the alloy. strength.

As a method to improve the wear resistance of the When the beryllium content is less than 0.6 percent, present alloys, it is necessary to adjust the precipitation the acicular structure, which is characteristic of the quantity of y If the value calculated by the above con- 40 present copper alloys, does not appear; moreover, the Version formula is below the Precipitation of 72 is not wear resistance of the alloys cannot be improved. Hownoticeable. If, on the other hand, the value iS above 18 ever when the Be content is higher than 2 percent, the the Shape of the 72'P p becomes Coarse and acicular structure disappears and a considerable dethe Wear resistance 88 Well 35 the tel'lSile Strength Of the rease in strength ccurs as in the case of an aluminum alloys are greatly decreased. Therefore, the value of the Content of more than 5 percent conversion formula is to be regulated 1n the range of 9 w the Silicon content is less than 09 percent, the to precipitate is neither formed in spherical shape nor is The following Table l lndlcates permissible limlts of it of fine grain Size but Whhn the Si Content is higher component of the present copper alloy percent than 3.5 percent, the K-phase in the copper-silicon apages by weight). pears, which is undesirable.

When the cobalt content is less than 0.5 percent, the' TABLE 1 precipitate is not in fine grain size and the tensile strength is not improved. But when the Co content is Al Be 5i CO higher than 2.5 percent, the aluminum equivalent of 6 I 5 06 2 9 3'5 05 to M balance 5 5 cobalt changes into a negative number, and the precipi- 1 tation of the 'y -phase is retarded. I Mechanical properties of further examples of the Characteristics of the present copper alloy are higher present copper alloy are shown in Table 3. These supehardness and wear resistance; in many cases, the tensile rior mechanical properties are gained not in the heatstrength and elongation are likewise improved. v treated state but in the as-cast state.

TABLE 3 Example Al Be Si Co Cu Tensile Elongation Hardness H, strength load 3000 kg kg/mm 6 8.2 0.79 2.3 2 86.71 65.2 0.3 360 BHN 7 7.3 0.6 1.5 1 89.6 53 4.1 300 BHN As shown in Table 3, the present copper alloy is very hard. It will be further seen that the alloy in spite of being very hard, is also very ductile.

A particular feature of the alloy is its superior wear resistance over the conventional aluminum-ironcopper alloys, which is due to the addition of beryllium, silicon and cobalt. The greatly improved wear resistance is, moreover, due to the very fine acicular structure of the matrix and the fine spherical precipitates.

Table 4 below shows the composition of a conventional aluminum-bronze alloy used in the comparison tests for wear resistance (in percentages by weight).

most curve, that of the conventional alloy is shown, expressed in terms of the wear width, when a load was moved over the specimen at a sliding speed of 0.94 m/second.

In FIG. 2, an alloy of the following composition was subjected to testing:

8.2 A1, 0.79 Be, 2.3 Si, 0.5 to 2.5 Co, balance copper.

In that figure, the effect of Co-addition on the tensile strength is illustrated. The content in cobalt is entered on the absicca in weight percentage, the tensile strength on the ordinate in kglmm The Al-equivalent is indicate on the right-hand side of the diagram. As

TABLE 4 mentioned before, the Co-contents of 0.5 to 2.5 weight percent are the satisfactory ones. Above 2.5 percent, A Fe Others Cu Hardness H the Al-equivalent of Co changes to a negative value and load 3000 kg the precipitation of the 'y -phase is retarded.

In FIGS. 3 and 4, the test machine (Ogoshi-type 05 balance 325 BHN Rapid Tester) is shown to consist of a cylindrical disk A of stainless steel, on which a load P is applied in the direction of the arrow X. The specimen to be tested is designated by B, the wear width by the letter f. In the test, a sliding speed of 0.94 m/sec was applied, the load In the accompanying drawings, the superior wear rewas 2.8 to 25.5 kg. sistance of the alloy according to the invention as well From the curves showing the result of the wearas the role played by different amonts of Co are more resistance test, it will be readily seen that the wear ref ll ill t d i th drawings, sistance of the present copper alloy is decidedly far su- FIG. 1 is a graphic representation of test results Perior to the Conventional aluminum'iron'copper yshowing the wear resistance of the inventive alloy as compared to conventional wear-resistant aluminum Whlle Present alloy descnbed above; an bronz; alloy containing Cu, Al, (I135; S11 and Co as the (principal components, we may a t ereto as secon ary e eadIZiIeGi; 2 shows the effect of different amounts of Co ments Sn Zn Mn l) Fe and Zr FIG 3 shows in from View a rapid weamesting m 03). One or more of these additional elements may chine for carrying out the comparison tests, and be mcorporated n the alloy. Test results have revealed FIG 4 is a Side View of the machine of i 3 that these additional elements have the following ef- FIG three Specimens were Subjected to testing. fects on the copper alloy according to the invention. They are designated as Example A, Example B and conventional wear-resistant aluminum bronze. 4O EFFECT OF TIN ADDITION The composition of the specimens was as follows (in W 2 V. weight percent): Tin is effective to improve the wear resistance and Example Cu Al Be Si Co Sn Zr Zn A 87.91 8.2 0.79 2.3 0.8 B 84.59 8.7 0.6] 2.2 0.9 1.7 0 3 I replace a part of the silicon if the intended objects require this.

However if the Sn content is increased o ver the limit value, the wear resistance will be impaired. An example of proper Sn addition is shown in Table 5.

The value of wear width in Table 5 is a value f, expressed in millimeters, and shown in FIG. 3. It will be understood that the smaller value the wear width has the higher is the wear resistance.

TABLE 5 Al Be Si Co Sn Cu Hardness H Wear width 8.2 0.79 2.3 0.8 87.91 340 MIN 2.88 8.2 0.78 2.2 0.8 2 86.02 360 BHN 2.35

Effect of Zinc Addition Zinc improves the tensile strength and elongation but if the amount added exceeds the limit value, the elongation will be greatly decreased. An example is shown in Table 6.

Effect of Manganese Addition Manganese improves the tensile strength but if the added amount exceeds the limit value, the tensile strength will be decreased. An example is shown in- Table 7.

Effect of Iron Addition lron makes the grain size finer but if the added amount exceeds the limit value, the wear resistance will be degraded. The limit value is up to 3 weight percent.

Effect of Zirconium Addition Zirconium makes the grain size finer, and even if it is added in an amount exceeding its limit, the effect will remain unchanged.

The effect of two or more additional elements is shown in Table 8 below.

the as-cast state without being subjected to heat treatment, and having excellent wear resistance under load, and high toughness.

2. A copper base alloy consisting of 7.3 weight A1, 0.6 wt% Be, 1.5 wt% Si, 1 wt% Co, and 89.6 wt% Cu,

the alloy being characterized by readiness to be used in the as-cast state without being subjected to heat treatment, and having excellent wear resistance under load, and high toughness.

3. A copper base alloy consisting of 8.2 weight Al, v

0.78 wt% Be, 2.2 wt% Si, 0.8 wt% Co, 2 wt% Sn, additionally containing as secondary elements at least one of the elements: up to 5 wt% Zn, up to 5 wt% Mn, up to 3 wt% Fe, and up to 0.3 wt% Zr, and the balance Cu the alloy being characterized by readiness to be used in the as-cast state without being subjected to heat treatment, and having excellent wear resistance under load, and high toughness.

4. A copper base alloy consisting of 8.1 weight Al, 0.81 wt% Be, 2.25 wt% Si, 0.6 wt% Co, 2.5 wt% Zn, additionally containing as secondary elements at least one of the elements: up to 5 wt% Sn, up to 5 wt% Mn, up to 3 wt% Fe, and up to 0.3 wt% Zr, and the balance Cu the alloy being characterized by readiness to be used in the as-cast state without being subjected to heat treatment, and having excellent wear resistance under load, and high toughness.

5. A copper base alloy consisting of 8.2 wt% Al, 0.81 wt% Be, 2.2 wt% Si, 0.7 wt% Co, 2.5 wt% Mn, additionally containing as secondary elements at least one of the elements: up to 5 wt% Sn, up to 5 wt% Zn, up to TABLE? Al Be Si Co Sn Zn Mn Zr Fe Cu Hardness Tensile strength Elongation BHN kg/mm 7.8 0.8 2 0.8 1.5 3.2 2 81.9 330 54.2 1 10.8 0.4 l 5 2 1.8 0.3 83.2 350 57.8 0.5 7.5 L5 1 l 0.5 4.2 2 3 2.5 77.7 320 53.5 4

Wherever in the specification and claims the expression balance Cu is used it means that the Cu content,

3 wt% Fe, and up to 0.3 wt% Zr, and the balance Cu the alloy being characterized by readiness to be used in while being within the limit range defined in the main the as-cast state without being subjected to heat treatclaim, is dependent on the amount of secondary element or elements added to the principal components. In other words, the copper value in some examples, as well as in the appended claims, is given by omitting the respective amounts and values of the impurities present, if any, such as for example 0.5 weight percent or less of Pb, P, As and possibly others.

What we claim is:

l. A copper base alloy consisting of 8.2 weight Al, 0.79 wt% Be, 2.3 wt% Si, 2 wt% Co, and 86.71 wt% Cu, the alloy being characterized by readiness to be used in ment, and having excellent wear resistance under load, and high toughness.

6. A copper base alloy consisting of 7.8 weight A1, 0.8 wt% Be, 2 wt% Si, 0.8 wt% Co, 1.5 wt% Sn, 3.2 wt% Zn, 2 wt% Mn, additionally containing as secondary elements at least one of the elements: up to 3 wt% Fe, and up to 0.3 wt% Zr, and the balance Cu the alloy being characterized by readiness to be used in the ascast state without being subjected to heat treatment,

- and having excellent wear resistance under load, and

high toughness.

5,850,644 n lu ust 2o, 974

Patent No Invento fls) S. Watangie et 8.1.

It is certified that err'or appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

I Column 5, line 56: numerical data in Table 1: for "$1", the correct values are 0.9 to 5.5 (instead of "9 and v cblumn 8, lines 25,155, 52 and 62 (that is claims. 5, 5+, 5 and 6, lines 5,; for all claims), before "the alloy being char- -acterized" (or, after "balance Cu") insert commas Signed and sealed this 19th day of November 1974.

(SEAL) Attest:

McCOY M. GIBSON JR. C. MARSHALL DANN Attesting Officer Commissioner of Patents FORM Po-wso (10-69) v USCOMWDC v V U.s. GOVERNMENT PRINTING OFF ICE lll O3-33l

Claims

2. A copper base alloy consisting of 7.3 weight % Al, 0.6 wt% Be, 1.5 wt% Si, 1 wt% Co, and 89.6 wt% Cu, the alloy being characterized by readiness to be used in the as-cast state without being subjected to heat treatment, and having excellent wear resistance under load, and high toughness.
3. A copper base alloy consisting of 8.2 weight % Al, 0.78 wt% Be, 2.2 wt% Si, 0.8 wt% Co, 2 wt% Sn, additionally containing as secondary elements at least one of the elements: up to 5 wt% Zn, up to 5 wt% Mn, up to 3 wt% Fe, and up to 0.3 wt% Zr, and the balance Cu the alloy being characterized by readiness to be used in the as-cast state without being subjected to heat treatment, and having excellent wear resistance under load, and high toughness.
4. A copper base alloy consisting of 8.1 weight % Al, 0.81 wt% Be, 2.25 wt% Si, 0.6 wt% Co, 2.5 wt% Zn, additionally containing as secondary elements at least one of the elements: up to 5 wt% Sn, up to 5 wt% Mn, up to 3 wt% Fe, and up to 0.3 wt% Zr, and the balance Cu the alloy being characterized by readiness to be used in the as-cast state without being subjected to heat treatment, and having excellent wear resistance under load, and high toughness.
5. A copper base alloy consisting of 8.2 wt% Al, 0.81 wt% Be, 2.2 wt% Si, 0.7 wt% Co, 2.5 wt% Mn, additionally containing as secondary elements at least one of the elements: up to 5 wt% Sn, up to 5 wt% Zn, up to 3 wt% Fe, and up to 0.3 wt% Zr, and the balance Cu the alloy being characterized by readiness to be used in the as-cast state without being subjected to heat treatment, and having excellent wear resistance under load, and high toughness.
6. A copper base alloy consisting of 7.8 weight % Al, 0.8 wt% Be, 2 wt% Si, 0.8 wt% Co, 1.5 wt% Sn, 3.2 wt% Zn, 2 wt% Mn, additionally containing as secondary elements at least one of the elements: up to 3 wt% Fe, and up to 0.3 wt% Zr, and the balance Cu the alloy being characterized by readiness to be used in the as-cast state without being subjected to heat treatment, and having excellent wear resistance under load, and high toughness.