High-plasticity free-cutting zinc alloy

Abstract

The present invention relates to a high-plasticity free-cutting zinc alloy, which includes the following components in percentage of weight: 1-10% Cu, 0.1-3.0% Bi, 0.01-1.5% Mn, 0.001-1% Ti and/or 0.01-0.3% Zr, optional component X, optional component Y, and a remainder component being Zn having less than or equal to 0.01% unavoidable impurities, wherein component X amounts to 0-1.0% and includes at least one element selected from Cr, V, Nb, Ni and Co; and component Y amounts to 0-1.0% and includes at least one element selected from B, As, P and rare earth metal. Compared with existing zinc alloys, the present invention has good machinability, higher plasticity and improved processability, which can be widely used in F connectors, pen manufacturing, socket connectors, locks and etc.

Claims

1. A free-cutting zinc alloy comprising the following components in percentage of weight: 2-7% Cu, 0.1-1.2% Bi, 0.1-0.4% Mn, 0.01-0.3% Ti, and 0.01-0.02% Zr, optional component X, optional component Y, and a remainder component being Zn having less than or equal to 0.01% unavoidable impurities, wherein component X amounts to 0-1.0% and comprises at least one element selected from Cr, V, Nb, Ni and Co; and component Y amounts to 0-1.0% and comprises at least one element selected from B, As, P and rare earth metal, wherein the zinc alloy has phases in an as-cast structure, and further comprises a matrix phase Zn and phases distributed in the matrix phase Zn including a plurality of Zn—Cu compounds, a plurality of herringbone intermetallic compounds, and free spherical Bi particles, the herringbone intermetallic compounds are mainly Zn—Mn—Cu—Ti compound and/or Zn—Mn—Cu—Zr compound with the remainder being Zn—Cu—Ti compound and/or Zn—Cu—Zr compound.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a typical as-cast structure of a high-plasticity free-cutting zinc alloy, comprising a matrix phase (Zn), a plurality of nearly-spherical Zn—Cu compounds, a plurality of herringbone intermetallic compounds, and free spherical Bi particles;

(2) FIG. 2 is a structure crushed after plastic machining;

(3) FIG. 3 is an energy spectrum of a Zn—Cu—Mn—Ti quaternary intermetallic compound;

(4) FIG. 4 is the shape of a Zn—Cu—Mn—Ti quaternary intermetallic compound;

(5) FIG. 5 is an energy spectrum of a Zn—Cu binary alloy;

(6) FIG. 6 is the shape of a Zn—Cu binary alloy;

(7) FIG. 7 is an energy spectrum of a Zn—Cu—Ti ternary alloy; and

(8) FIG. 8 is the shape of a Zn—Cu—Ti ternary alloy.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

(9) To enable a further understanding of the innovative and technological content of the invention herein, refer to the detailed description of the invention and the accompanying drawings below:

(10) This alloy is cast by a line frequency furnace, an intermediate frequency furnace or a reverberatory furnace by means of continuous casting or die casting to obtain a billet; then, the desired bars, tubes or profile billets are obtained by means of hot extrusion, where the temperature for hot extrusion is 180° C.-380° C.; and finally, bars, wires and profile products of various specifications are obtained by cold drawing. The performance test datas of the embodiments refer to Table 1. The alloys of comparing examples CN10182615B (Patent No. ZL201010147727.4) and CN101851713B (Patent No. ZL201010205423.9) are cast according to the methods disclosed in the respective patents. The alloys of two above stated comparing examples and the alloy of the comparing example C3604 are manufactured according to the same method as in this embodiment and respectively tested in terms of the related performance data.

Embodiments 1, 2, 3 and 4

(11) Production process: a master alloy billet with a diameter of 170 mm is obtained by semi-continuous casting and manufactured by hot extrusion to a bar billet at 380° C., and the bar billet is manufactured by joint drawing to a bar of a desired diameter.

(12) The finished bar product is manufactured into a part by drilling it by a cam-type automatic lathe. The cuttings are fragile and the machining efficiency may reach 90% of that of C3604 lead-containing brass (the machining efficiency refers to the ratio of the number of parts of a same shape and size cut by a same cutter under same cutting parameters. For example, assuming that, for C3604 copper alloy, 100 parts are manufactured within 1 min, and for zinc alloy, 90 parts are manufactured within 1 min, the machining efficiency is 90%; similarly hereinafter). The surfaces of the parts may be manufactured by nickeling, chroming, tinning, etc.

Embodiments 5, 6, 7, 8, 9 and 10

(13) Production process: the alloy is smelted by induction heating and manufactured by die casting to obtain an alloy ingot; the alloy ingot is manufactured into a bar billet by extrusion at 240° C.; the bar billet is manufactured to a zinc alloy bar by a crawler-type broaching machine; and, after polished and straightened, the zinc alloy bar is manufactured into an electronic product in a numerically controlled lathe. For parts of a same specification, the machining efficiency by using the numerically controlled lathe may reach 85% of that of C3604 lead-containing brass bars. The surfaces of the parts may be manufactured by nickeling, chroming, tinning, etc.

Embodiments 11, 12 and 13

(14) Production process: the alloy is smelted by induction heating and manufactured by die casting to obtain a master alloy ingot; the alloy ingot is manufactured into an alloy bar billet by extrusion at 180° C.; the alloy bar billet is manufactured into a size of a finished product by multi-die drawing machine; and then, the alloy bar billet is diameter-reduced, straightened and polished to obtain a finished product by joint drawing. By dry machining using a cam type automatic lathe, the machining efficiency may reach 80% of that of the C3604 lead-containing brass of the same specification.

Embodiments 14, 15, 16 and 17

(15) Production process: a master alloy ingot billet is obtained by continuous casting and then manufactured into a profile of 42 mm*15 mm by extrusion at 240° C.

(16) After discharged, the profile is manufactured by a special drill press, with a depth of pores Φ3 mm in diameter being 20 mm. More than 20 pores may be continuously drilled without cooling to obtain a finished padlock body part. The machining efficiency may reach 90% of that of C3604 lead-containing brass bars.

(17) The surfaces of the body part may be manufactured by nickeling, chroming, tinning, etc.

Embodiments 18, 19 and 20

(18) Production process: a master alloy ingot billet is obtained by continuous casting and then manufactured by extrusion at 300° C.

(19) The master alloy ingot billet is manufactured into a bar of a desired diameter by joint drawing. After discharged, the bar is manufactured by a special drill press, with a depth of pores Φ9.8 mm in diameter being 20 mm. More than 20 pores may be continuously drilled to obtain a finished metal pen part. The machining efficiency may reach 85% of that of C3604 lead-containing brass bars.

Embodiments 21, 22 and 23

(20) Production process: a master alloy ingot billet is obtained by continuous casting and then manufactured into a bar billet of a proper specification by extrusion at 320° C.

(21) The bar billet is manufactured into a bar of a desired diameter by joint drawing.

(22) After discharged, the bar is manufactured by a special drill press, with a depth of pores Φ3 mm in diameter being 35 mm. More than 20 pores may be continuously drilled to obtain a finished metal pen part. The machining efficiency may reach 85% of that of C3604 lead-containing brass bars.

Embodiments 24, 25, 26 and 27

(23) Production process: a master alloy ingot billet is obtained by continuous casting and then manufactured into a bar Φ25 mm in diameter by extrusion at 320° C.; and the bar is manufactured into a bar in a desired diameter by joint drawing.

(24) After discharged, the bar is manufactured by a special drill press, with a depth of pores Φ2.8 mm in diameter being 25 mm. More than 20 pores may be continuously drilled. The machining efficiency may reach 85% of that of C3604 lead-containing brass bars.

Embodiments 28, 29 and 30

(25) Production process: a master alloy ingot billet is obtained by continuous casting and then manufactured into a bar Φ12 mm in diameter by extrusion at 340° C.; and the bar is manufactured into a bar in a desired diameter by joint drawing.

(26) After discharged, the bar is manufactured by a cam lathe. More than 200 parts may be continuously produced without cooling to obtain a finished metal pen part. The machining efficiency may reach 90% of that of C3604 lead-containing brass bars.

Embodiments 31 and 32

(27) Production process: a master alloy ingot billet is obtained by continuous casting and then manufactured into a wire 10 mm in diameter by peeling, diameter reducing and stretching.

(28) After discharged, the wire is manufactured by a special drill press, with a depth of pores Φ5 mm in diameter being 30 mm. More than 20 pores may be continuously drilled to obtain a finished part. The machining efficiency may reach 80% of that of C3604 lead-containing brass bars.

(29) TABLE-US-00001 TABLE 1 Comparison between embodiments of alloy of the present invention and comparing alloys in terms of components and performance Alloys of the invention and Alloy components (wt %) comparing examples Cu Bi Mn Ti Zr Cr V Nb Ni B 1 2.53 0.28 0.89 0.34 0.27 2 3.12 2.10 1.22 0.19 0.16 3 4.15 0.38 0.19 4 7.54 0.16 0.08 0.01 5 6.07 0.15 0.21 0.098 0.14 6 5.89 0.35 0.11 0.11 0.18 7 1.51 2.04 0.25 0.89 8 5.03 0.51 0.45 0.18 0.12 9 4.51 0.75 0.53 0.33 0.23 10 3.53 1.25 1.32 11 9.23 0.82 0.05 0.02 0.15 12 4.02 0.85 1.02 0.16 0.21 13 3.02 2.54 0.65 0.26 14 2.51 1.75 0.39 0.71 0.02 15 4.45 0.88 0.67 0.001 0.02 16 1.02 2.98 0.15 0.25 17 3.01 0.43 0.36 0.12 0.03 18 4.27 0.91 0.80 0.28 19 3.21 0.77 1.42 0.25 20 5.21 0.25 0.28 0.017 21 4.59 0.59 0.19 0.31 0.06 Co 0.03 22 5.59 2.31 0.32 0.43 0.05 23 2.58 0.32 1.23 0.22 24 3.51 0.65 0.98 0.60 25 6.59 1.89 1.36 0.54 0.23 26 3.14 1.45 1.49 0.74 27 8.12 0.18 0.13 0.009 0.29 0.01 0.01 0.005 28 5.55 0.49 0.42 0.21 29 2.01 0.20 0.15 0.82 30 4.36 0.11 0.59 0.09 31 6.51 0.35 0.15 0.19 32 9.98 0.12 0.01 0.002 0.01 ZL201010147727.4 1.2 0.5 Mg: 0.06 Al: 7.2 ZL201010205423.9 2.1 0.08 0.08 Al: 0.2 Mg: 0.18 Sb: 0.06 C3604 61.5 Pb: 3.01 Performance Alloys of the Tensile Machinability/% invention and Alloy components (wt %) strength/ Plasticity/ Hardness/ (compared comparing examples P As RE Zn MPa % Hv with C3604) 1 The 360 23 95 85 remaining 2 The 360 23 95 85 remaining 3 0.02 The 330 20 90 85 remaining 4 The 485 16 120 90 remaining 5 The 385 19 95 85 remaining 6 The 365 25 93 85 remaining 7 0.03 The 405 22 100 90 remaining 8 The 485 25 120 85 remaining 9 The 485 25 120 85 remaining 10 The 430 24 112 80 remaining 11 The 485 16 120 90 remaining 12 The 440 23 105 80 remaining 13 The 405 22 95 90 remaining 14 0.01 The 405 22 95 90 remaining 15 The 445 25 115 85 remaining 16 The 365 22 95 90 remaining 17 0.04 The 430 20 100 85 remaining 18 The 465 24 105 80 remaining 19 The 450 20 105 85 remaining 20 The 355 19 90 85 remaining 21 0.05 The 385 19 90 85 remaining 22 0.02 The 445 17 110 90 remaining 23 The 445 17 110 90 remaining 24 0.12 The 445 17 110 90 remaining 25 The 445 17 110 90 remaining 26 0.04 The 460 23 115 85 remaining 27 0.04 0.004 The 385 16 90 90 remaining 28 The 385 25 93 85 remaining 29 0.003 The 370 25 90 80 remaining 30 The 420 25 90 80 remaining 31 The 385 25 93 85 remaining 32 The 485 16 120 90 remaining ZL201010147727.4 The 360 10 72 63 remaining ZL201010205423.9 The 402 5 130 81 remaining C3604 The 98 remaining