JP4479270B2 - Manufacturing method of electrode wire for wire electric discharge machining - Google Patents

Description

  The present invention relates to a method of manufacturing an electrode wire used for wire electric discharge machining, and more particularly to a method of manufacturing an electrode wire for wire electric discharge machining that can manufacture an electrode wire having a high electric discharge machining speed with high productivity.

  An electrode wire using a Cu—Zn alloy is used as an electrode wire for wire electric discharge machining. Since this type of electrode wire has excellent discharge characteristics, there are advantages that the machining speed in electric discharge machining is high and machining accuracy is high, and that the cost is low.

  Conventionally, a single alloy containing 32 to 36 wt% Zn (Cu-35 wt% Zn alloy, ie, 65/35 brass wire) has been used as this type of electrode wire. However, since this electrode wire has a low electric discharge machining speed, it cannot satisfy the high electric discharge machining speed that has become important in recent years.

  Therefore, in Patent Document 1, a first coating step in which a Zn layer is coated on the outer periphery of a core material made of Cu or Cu alloy, and a coated wire is formed by coating a Cu-Zn layer having a low Zn concentration on the outer periphery of the Zn layer. A second covering step, a diameter reducing step for reducing the diameter of the coated wire (this step may be omitted), and heat-treating the coated wire to change the Zn in the Zn layer to the Cu-Zn layer. The wire is subjected to a heat treatment step for forming a Cu-Zn diffusion layer having a high Zn concentration by diffusing into a wire, and a final reduction step to obtain an electrode wire having a desired wire diameter by reducing the diameter of the coated wire. It has been proposed to produce an electrode wire for electric discharge machining.

  Note that diameter reduction is synonymous with wire drawing.

JP 2002-172529 A

  However, the electrode wire for wire electric discharge machining in Patent Document 1 has a high Zn concentration of 38 to 50% by weight in the Cu—Zn diffusion layer obtained in the heat treatment step. The property is low (it is difficult to draw or breakage). For this reason, productivity in electrode wire production is extremely inferior.

  Then, the objective of this invention is providing the manufacturing method of the electrode wire for wire electrical discharge machining which solves the said subject and can manufacture an electrode wire with high electrical discharge machining speed with high productivity.

In order to achieve the above object, the manufacturing method of the present invention includes a first coating step of coating a Zn layer on the outer periphery of a core material made of Cu or a Cu alloy, and a low Zn concentration Cu—Zn layer on the outer periphery of the Zn layer. A second coating step for coating to form a coated wire, a first diameter reducing step for reducing the diameter of the coated wire , and heat-treating the coated wire at 500 to 700 ° C. for 1 to 5 hours, the Zn A first heat treatment step for diffusing Zn in the layer into the Cu-Zn layer to form a Cu-Zn diffusion layer having a high Zn concentration, a second diameter reduction step for reducing the diameter of the coated wire, and a post-heat treatment step A second heat treatment step for softening the coated wire by subjecting the coated wire to a heat treatment at 450 ° C. for 0.5 to 2 hours, and reducing the diameter of the coated wire, thereby giving the coated wire a desired tensile strength. A third diameter reduction step and Those having.

  In the first diameter reduction step, the diameter reduction processing may be performed so that the processing degree of the Cu—Zn layer is 50 to 80%.

  In the first heat treatment step, heat treatment may be performed at 500 to 700 ° C. for 1 to 5 hours.

  In the second diameter reduction step, the diameter reduction processing may be performed so that the processing degree of the Cu—Zn diffusion layer is 50 to 80%.

  In the third diameter reducing step, the diameter reducing process may be performed so that the degree of processing of the Cu—Zn diffusion layer becomes 70 to 98%.

  In the first coating step, a Zn layer may be coated by vertically attaching a Zn tape to the outer periphery of the core material, and in the second coating step, a Cu—Zn tape may be vertically applied to the outer periphery of the Zn layer.

  The core material is Cu-0.02-0.2 wt% Zr alloy, Cu-0.15-0.25 wt% Sn-0.15-0.25 wt% In alloy, Cu-0.15-0 .70 wt% Sn alloy, Cu-0.10 to 0.70 wt% In alloy, Cu-5 to 30 wt% Zn alloy, Cu-5 to 30 wt% Zn alloy with Zr, Cr, Si, Mg, Al , Fe, P, Ni, Ag, Sn may be any alloy among the alloys to which one or more additives are added.

  In the first heat treatment step, the Zn concentration in the Cu—Zn diffusion layer may be 38 to 50 wt% after the heat treatment.

  The present invention exhibits the following excellent effects.

(1) An electrode wire having a high electric discharge machining speed can be manufactured. (2) The electrode wire can be manufactured with high productivity.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

  FIG.1 and FIG.2 shows the covering wire in the middle of manufacture in the manufacturing method of the electrode wire for wire electric discharge machining which concerns on this invention. As shown in FIG. 1, the coated wire 1 has a Zn layer 3 coated on the outer periphery of a core material 2 made of Cu or a Cu alloy, and a low Zn concentration Cu—Zn layer 4 is coated on the outer periphery of the Zn layer 3. It is coated. On the other hand, as shown in FIG. 2, the electrode wire 5 is formed by forming a Cu—Zn diffusion layer 6 having a high Zn concentration on the outer periphery of the core material 2 made of Cu or Cu alloy. The Cu—Zn diffusion layer 6 is formed by heat treating the Zn layer 3 and the Cu—Zn layer 4.

  In the manufacturing method of the present invention, new steps are added to the manufacturing method described in Patent Document 1, and various conditions for appropriately performing each step are set.

  Hereinafter, the details in each step of the production method of the present invention will be described in the order of execution of the steps.

  First, a first coating step for coating the outer periphery of the core material 2 with the Zn layer 3 is performed.

  For the core material 2, Cu alone or Cu alloy is used. The Cu alloy includes a Cu-0.02-0.2 wt% Zr alloy, or a Cu-0.15-0.25 wt% Sn-0.15-0.25 wt% In alloy, or a Cu-0 .15 to 0.70 wt% Sn alloy, or Cu-0.10 to 0.70 wt% In alloy, or Cu-5 to 30 wt% Zn alloy, or Cu-5 to 30 wt% Zn alloy An alloy to which one or more additives of Cr, Si, Mg, Al, Fe, P, Ni, Ag, and Sn are added may be used. Since these alloys have good conductivity and high heat resistance, they are effective in improving the performance of electrode wires in electric discharge machining.

  For the Zn layer 3, it is preferable to use a Zn tape made of Zn alone. The Zn layer 3 is covered by vertically attaching the Zn tape to the outer periphery of the core material 2. Advantages of using the Zn tape will be described later.

  Next, the 2nd coating step which coat | covers the Cu-Zn layer 4 on the outer periphery of the Zn layer 3, and forms the covering wire 1 is performed.

  For the Cu—Zn layer 4, a low Zn concentration Cu—Zn alloy is used. Here, the low Zn concentration Cu—Zn alloy is one having a Zn concentration lower than the Cu—Zn diffusion layer 6 described later, and refers to, for example, Cu-33 to 37 wt% Zn.

  For the Cu—Zn layer 4, a Cu—Zn tape made of a Cu—Zn alloy may be used. This Cu—Zn tape is vertically attached to the outer periphery of the Zn layer 3, and the butted portions of the Cu—Zn tape are welded together to cover the Cu—Zn layer 4. When using a Cu-Zn tape, a first covering step is performed by vertically covering the Zn tape, and a first closing step of welding and joining the butted portions of the Zn tape (both ends in the width direction of the Zn tape). And a second covering step in which the Cu-Zn tape butting portions (both ends in the width direction of the Cu-Zn tape) are welded and joined together, Can be performed continuously, and the manufacturing cost is reduced.

  Next, a first diameter reduction step for reducing the diameter of the coated wire 1 is performed.

  In this first diameter reduction step, diameter reduction processing is performed so that the degree of processing of the Cu—Zn layer 4 is 50 to 80%. Thereby, the interface between the core material 2 and the Zn layer 3 and the interface between the Zn layer 3 and the Cu—Zn layer 4 can be well adhered without impairing the drawability of the coated wire 1. If the degree of processing is less than 50%, the adhesion at the interface cannot be improved, and as a result, the drawability in the subsequent diameter reduction processing is lowered. Moreover, if the degree of work is greater than 80%, the Cu—Zn layer 4 is work-hardened, and the drawability in the subsequent diameter reduction work is lowered.

  The degree of processing is a numerical value obtained by subtracting the diameter after processing from the diameter before processing and dividing by the diameter before processing. For example, when the diameter of the coated wire 1 having a diameter of 1 is reduced to a diameter of 0.2, the degree of processing is 80%.

  Next, the 1st heat treatment step which heat-processes this covered wire 1 is performed.

In this first heat treatment step, the coated wire 1 in FIG. 1 is subjected to heat treatment at 500 to 700 ° C. for 1 to 5 hours to diffuse Zn in the Zn layer 3 into the Cu—Zn layer 4 as shown in FIG. Then, a Cu-Zn diffusion layer 6 having a high Zn concentration is formed. That is, the electrode wire 5 in which the high Zn concentration Cu—Zn diffusion layer 6 is formed on the outer periphery of the core material 2 is obtained. Here, the high Zn concentration means 38 to 50% by weight. If the heat treatment temperature is less than 500 ° C. or the heat treatment time is less than 1 hour, Zn is not sufficiently diffused and the drawability is lowered. Further, if the heat treatment temperature is higher than 700 ° C. or the heat treatment time is longer than 5 hours, the Zn diffusion proceeds excessively, and the Zn concentration of the Cu—Zn diffusion layer 6 is higher than desired. It will decline.

  Here, the reason why the Zn concentration of the Cu—Zn diffusion layer 6 is decreased is that Zn is evaporated from the surface of the Cu—Zn layer 4 in the coated wire 1 or the Cu component of the core material 2 is Cu— in the course of the heat treatment. This is to diffuse into the Zn diffusion layer 6.

  Next, a second diameter reducing step for reducing the diameter of the electrode wire 5 is performed.

  In this second diameter reduction step, the diameter reduction processing is performed so that the degree of processing of the Cu—Zn diffusion layer 6 is 50 to 80%. Thereby, the interface between the Cu—Zn diffusion layer 6 and the core material 2 can be closely adhered. If the degree of processing is less than 50%, the adhesion at the interface cannot be improved, and as a result, the drawability in the subsequent diameter reduction processing is lowered. Further, if the degree of work is greater than 80%, the Cu—Zn diffusion layer 6 is work-hardened and the drawability in the subsequent diameter reduction work is lowered.

  Next, a second heat treatment step for heat treating the electrode wire 5 is performed.

  In this second heat treatment step, the electrode wire 5 in FIG. 2 is subjected to a heat treatment at 400 to 500 ° C. for 0.5 to 2 hours, thereby giving the electrode wire 5 an appropriate wire drawing property without promoting Zn re-diffusion. The electrode wire 5 is softened to the extent. If the heat treatment temperature is less than 400 ° C. or the heat treatment time is less than 0.5 hour, the electrode wire 5 cannot be softened and the drawability at the next third diameter reduction step is lowered. . If the heat treatment temperature is higher than 500 ° C. or the heat treatment time is longer than 2 hours, Zn re-diffusion proceeds, and the Zn concentration of the Cu—Zn diffusion layer 6 is higher than desired. It will decline. If the Zn concentration of the Cu—Zn diffusion layer 6 is lower than desired, the electrical discharge machining speed using the electrode wire is reduced.

  Next, a third diameter reducing step for reducing the diameter of the electrode wire 5 is performed.

In this third diameter reduction step, the diameter reduction processing is performed so that the processing degree of the Cu—Zn diffusion layer 6 becomes 70 to 98%. Thereby, desired tensile strength can be given to the electrode wire 5. If the degree of processing is less than 70%, the desired tensile strength cannot be obtained. If the degree of processing is greater than 98 %, the Cu—Zn diffusion layer 6 exceeds the processing limit, and disconnection occurs at the time of wire drawing in the third diameter reduction step.

  Here, the reason why the electrode wire 5 has a desired tensile strength is that when performing the electric discharge machining, the electric discharge machining is performed while applying tension to the wire electric discharge machining electrode wire. Without strength, the wire electric discharge machining electrode wire is broken during wire electric discharge machining.

  In the third diameter reduction step, diameter reduction processing is performed so as to obtain an electrode wire having a finished outer diameter of 0.1 to 0.4 mm.

  The wire electric discharge machining electrode wire manufactured through the above manufacturing steps has a high electric discharge machining speed because the Zn concentration of the Cu—Zn diffusion layer 6 is high. In addition, this wire electric discharge machining electrode wire has good drawing workability during production and therefore has high production efficiency, and thus can be produced at low cost. That is, the present invention can provide an inexpensive wire electric discharge machining electrode wire.

  In the first heat treatment step, the Zn concentration in the Cu—Zn diffusion layer 6 after the heat treatment is set to 38 to 50% by weight as desired for the electrode wire 5 without impairing the drawability of the electrode wire 5. This is to provide a high Zn concentration. If the Zn concentration of the Cu—Zn diffusion layer 6 is less than 38% by weight, the processing speed when performing electrical discharge machining using the electrode wire is lowered. Further, if the Zn concentration of the Cu—Zn diffusion layer 6 is larger than 50% by weight, the wire drawing workability is remarkably lowered.

  In the background art, the Zn concentration after the heat treatment step is as high as 38 to 50% by weight, so that the wire drawing workability in the final diameter reduction step is low. Even if the concentration is 38 to 50% by weight, since the softening is subsequently achieved in the second heat treatment step, high wire drawing workability can be obtained in the third diameter reduction step.

  In order to clarify the effects of the present invention, the electrode wires (Examples) manufactured according to the present invention were compared with other electrode wires (Comparative Examples and Conventional Examples) from various viewpoints. First, the manufacturing method and various conditions of each electrode wire are clarified.

Example 1
A Cu-0.19 wt% Sn-0.2 wt% In alloy wire having a diameter of 4.0 mm is used as the core material 2, and a thickness of 0.2 mm and a width of 13 mm of Zn tape is vertically attached to the core material 2. A coated wire 1 having a diameter of 5.4 mm is formed by vertically attaching a Cu-Zn tape (Cu-35 wt% Zn) of 0.50 mm and welding the butted portions. The coated wire 1 is subjected to cold drawing at a workability of 60%, and then heat-treated at 600 ° C. for 2 hours to form a Cu-45 wt% Zn diffusion layer 6 to form the electrode wire 5. The electrode wire 5 is subjected to a cold drawing process with a working degree of 65%, followed by a heat treatment at 450 ° C. for 1 hour. Finally, the electrode wire 5 is passed through a plurality of wire drawing dies and subjected to diameter reduction processing at a processing degree of 90% to produce an electrode wire having a wire diameter of 0.25 mm.

(Example 2)
As the core material 2, a Cu-0.16 wt% Zr alloy wire having a diameter of 4.0 mm is used. Otherwise, an electrode wire having a wire diameter of 0.25 mm is manufactured in the same manner as in Example 1.

(Example 3)
A Cu-10 wt% Zn alloy wire having a diameter of 4.0 mm is used as the core material 2. Otherwise, an electrode wire having a wire diameter of 0.25 mm is manufactured in the same manner as in Example 1.

Example 4
As the core material 2, a Cu-0.3 wt% Sn alloy wire having a diameter of 4.0 mm is used. Otherwise, an electrode wire having a wire diameter of 0.25 mm is manufactured in the same manner as in Example 1.

  In these examples, a Cu alloy is used as the core material 2, but the present invention is not limited to this, and Cu alone may be used as the core material 2.

(Comparative Example 1)
A Cu-0.19 wt% Sn-0.2 wt% In alloy wire having a diameter of 4.0 mm is used as the core material 2, and a thickness of 0.2 mm and a width of 13 mm of Zn tape is vertically attached to the core material 2. A coated wire 1 having a diameter of 5.4 mm is formed by vertically attaching a Cu-Zn tape (Cu-35 wt% Zn) of 0.50 mm and welding the butted portions. The coated wire 1 is subjected to cold drawing at a workability of 60%, and then heat-treated at 400 ° C. for 4 hours to form the Cu-45Zn diffusion layer 6 to form the electrode wire 5. The electrode wire 5 is subjected to a cold drawing process with a working degree of 65%, followed by a heat treatment at 450 ° C. for 1 hour. Finally, the electrode wire 5 is passed through a plurality of wire drawing dies and subjected to diameter reduction processing at a processing degree of 90% to produce an electrode wire having a wire diameter of 0.25 mm.

  That is, Comparative Example 1 is the same as Example 1 except that the condition of the first heat treatment step is 400 ° C. × 4 hours. Therefore, the heat treatment temperature in the first heat treatment step is insufficient for the conditions of the present invention.

(Comparative Example 2)
A Cu-0.19 wt% Sn-0.2 wt% In alloy wire having a diameter of 4.0 mm is used as the core material 2, and a thickness of 0.2 mm and a width of 13 mm of Zn tape is vertically attached to the core material 2. A coated wire 1 having a diameter of 5.4 mm is formed by vertically attaching a Cu-Zn tape (Cu-35 wt% Zn) of 0.50 mm and welding the butted portions. The coated wire 1 is subjected to cold drawing at a workability of 60%, and then heat treated at 600 ° C. for 0.5 hours to form the Cu-45Zn diffusion layer 6 to form the electrode wire 5. The electrode wire 5 is subjected to a cold drawing process with a working degree of 65%, followed by a heat treatment at 450 ° C. for 1 hour. Finally, the electrode wire 5 is passed through a plurality of wire drawing dies and subjected to diameter reduction processing at a processing degree of 90% to produce an electrode wire having a wire diameter of 0.25 mm.

  That is, Comparative Example 2 is the same as Example 1 except that the condition of the first heat treatment step is 600 ° C. × 0.5 hours. Therefore, the heat treatment time in the first heat treatment step is insufficient for the conditions of the present invention.

(Comparative Example 3)
A Cu-0.19 wt% Sn-0.2 wt% In alloy wire having a diameter of 4.0 mm is used as the core material 2, and a thickness of 0.2 mm and a width of 13 mm of Zn tape is vertically attached to the core material 2. A coated wire 1 having a diameter of 5.4 mm is formed by vertically attaching a Cu-Zn tape (Cu-35 wt% Zn) of 0.50 mm and welding the butted portions. The coated wire 1 is subjected to cold drawing at a workability of 60%, and then heat-treated at 600 ° C. for 6 hours to form the Cu-45Zn diffusion layer 6 to form the electrode wire 5. The electrode wire 5 is subjected to a cold drawing process with a working degree of 65%, followed by a heat treatment at 450 ° C. for 1 hour. Finally, the electrode wire 5 is passed through a plurality of wire drawing dies and subjected to diameter reduction processing at a processing degree of 90% to produce an electrode wire having a wire diameter of 0.25 mm.

  That is, Comparative Example 3 is the same as Example 1 except that the condition of the first heat treatment step is 600 ° C. × 6 hours. Therefore, the heat treatment time in the first heat treatment step exceeds the conditions of the present invention.

(Comparative Example 4)
A Cu-0.19 wt% Sn-0.2 wt% In alloy wire having a diameter of 4.0 mm is used as the core material 2, and a thickness of 0.2 mm and a width of 13 mm of Zn tape is vertically attached to the core material 2. A coated wire 1 having a diameter of 5.4 mm is formed by vertically attaching a Cu-Zn tape (Cu-35 wt% Zn) of 0.50 mm and welding the butted portions. The coated wire 1 is subjected to cold drawing at a workability of 60%, and then heat-treated at 800 ° C. for 4 hours to form the Cu-45Zn diffusion layer 6 to form the electrode wire 5. The electrode wire 5 is subjected to cold drawing at a workability of 65%, and then heat treatment at 450 ° C. for 1 hour. Finally, the electrode wire 5 is passed through a plurality of wire drawing dies and subjected to diameter reduction processing at a workability of 90% to produce an electrode wire having a wire diameter of 0.25 mm.

  That is, Comparative Example 4 is the same as Example 1 except that the condition of the first heat treatment step is 800 ° C. × 4 hours. Therefore, the heat treatment temperature in the first heat treatment step exceeds the conditions of the present invention.

(Comparative Example 5)
A Cu-0.19 wt% Sn-0.2 wt% In alloy wire having a diameter of 4.0 mm is used as the core material 2, and a thickness of 0.2 mm and a width of 13 mm of Zn tape is vertically attached to the core material 2. A coated wire 1 having a diameter of 5.4 mm is formed by vertically attaching a Cu-Zn tape (Cu-35 wt% Zn) of 0.50 mm and welding the butted portions. The coated wire 1 is subjected to cold drawing at a workability of 60%, and then heat treated at 600 ° C. for 2 hours to form the Cu-45Zn diffusion layer 6 to form the electrode wire 5. The electrode wire 5 is subjected to cold drawing at a working degree of 40%, and then heat treatment at 450 ° C. for 1 hour. Finally, the electrode wire 5 is passed through a plurality of wire drawing dies and subjected to diameter reduction processing at a processing degree of 90% to produce an electrode wire having a wire diameter of 0.25 mm.

  That is, Comparative Example 5 is the same as Example 1 except that the condition of the second diameter reduction step is a processing degree of 40%. Therefore, the degree of processing in the second diameter reduction step is insufficient for the conditions of the present invention.

(Comparative Example 6)
A Cu-0.19 wt% Sn-0.2 wt% In alloy wire having a diameter of 4.0 mm is used as the core material 2, and a thickness of 0.2 mm and a width of 13 mm of Zn tape is vertically attached to the core material 2. A coated wire 1 having a diameter of 5.4 mm is formed by vertically attaching a Cu-Zn tape (Cu-35 wt% Zn) of 0.50 mm and welding the butted portions. The coated wire 1 is subjected to cold drawing at a workability of 60%, and then heat treated at 600 ° C. for 2 hours to form the Cu-45Zn diffusion layer 6 to form the electrode wire 5. The electrode wire 5 is subjected to cold drawing with a workability of 90% and then heat treatment at 450 ° C. for 1 hour. Finally, the electrode wire 5 is passed through a plurality of wire drawing dies and subjected to diameter reduction processing at a processing degree of 90% to produce an electrode wire having a wire diameter of 0.25 mm.

  That is, Comparative Example 5 is the same as Example 1 except that the condition of the second diameter reduction step is a processing degree of 90%. Therefore, the degree of processing in the second diameter reduction step exceeds the condition of the present invention.

(Comparative Example 7)
A Cu-0.19 wt% Sn-0.2 wt% In alloy wire having a diameter of 4.0 mm is used as the core material 2, and a thickness of 0.2 mm and a width of 13 mm of Zn tape is vertically attached to the core material 2. A coated wire 1 having a diameter of 5.4 mm is formed by vertically attaching a Cu-Zn tape (Cu-35 wt% Zn) of 0.50 mm and welding the butted portions. The coated wire 1 is subjected to cold drawing at a workability of 60%, and then heat treated at 600 ° C. for 2 hours to form the Cu-45Zn diffusion layer 6 to form the electrode wire 5. The electrode wire 5 is subjected to cold drawing with a processing degree of 65%, and then heat treatment at 300 ° C. for 1 hour. Finally, the electrode wire 5 is passed through a plurality of wire drawing dies and subjected to diameter reduction processing at a processing degree of 90% to produce an electrode wire having a wire diameter of 0.25 mm.

  That is, Comparative Example 7 is the same as Example 1 except that the condition of the second heat treatment step is 300 ° C. × 1 hour. Therefore, the heat treatment temperature in the second heat treatment step is insufficient for the conditions of the present invention.

(Comparative Example 8)
A Cu-0.19 wt% Sn-0.2 wt% In alloy wire having a diameter of 4.0 mm is used as the core material 2, and a thickness of 0.2 mm and a width of 13 mm of Zn tape is vertically attached to the core material 2. A coated wire 1 having a diameter of 5.4 mm is formed by vertically attaching a Cu-Zn tape (Cu-35 wt% Zn) of 0.50 mm and welding the butted portions. The coated wire 1 is subjected to cold drawing at a workability of 60%, and then heat treated at 600 ° C. for 2 hours to form the Cu-45Zn diffusion layer 6 to form the electrode wire 5. The electrode wire 5 is subjected to cold drawing with a workability of 65% and then heat treatment at 600 ° C. for 1 hour. Finally, the electrode wire 5 is passed through a plurality of wire drawing dies and subjected to diameter reduction processing at a processing degree of 90% to produce an electrode wire having a wire diameter of 0.25 mm.

  That is, Comparative Example 8 is the same as Example 1 except that the condition of the second heat treatment step is 600 ° C. × 1 hour. Therefore, the heat treatment temperature in the second heat treatment step exceeds the condition of the present invention.

(Comparative Example 9)
A Cu-0.19 wt% Sn-0.2 wt% In alloy wire having a diameter of 4.0 mm is used as the core material 2, and a thickness of 0.2 mm and a width of 13 mm of Zn tape is vertically attached to the core material 2. A coated wire 1 having a diameter of 5.4 mm is formed by vertically attaching a Cu-Zn tape (Cu-35 wt% Zn) of 0.50 mm and welding the butted portions. The coated wire 1 is subjected to cold drawing at a workability of 60%, and then heat treated at 600 ° C. for 2 hours to form the Cu-45Zn diffusion layer 6 to form the electrode wire 5. The electrode wire 5 is subjected to a cold drawing process with a working degree of 65%, followed by a heat treatment at 450 ° C. for 1 hour. Finally, the electrode wire 5 is passed through a plurality of wire drawing dies and subjected to diameter reduction processing at a processing degree of 65% to produce an electrode wire having a wire diameter of 0.25 mm.

  That is, Comparative Example 9 is the same as Example 1 except that the condition of the third diameter reduction step is a processing degree of 65%. Therefore, the degree of processing in the third diameter reduction step is insufficient for the conditions of the present invention.

(Comparative Example 10)
A Cu-0.19 wt% Sn-0.2 wt% In alloy wire having a diameter of 4.0 mm is used as the core material 2, and a thickness of 0.2 mm and a width of 13 mm of Zn tape is vertically attached to the core material 2. A coated wire 1 having a diameter of 5.4 mm is formed by vertically attaching a Cu-Zn tape (Cu-35 wt% Zn) of 0.50 mm and welding the butted portions. The coated wire 1 is subjected to cold drawing at a workability of 60%, and then heat treated at 600 ° C. for 2 hours to form the Cu-45Zn diffusion layer 6 to form the electrode wire 5. The electrode wire 5 is subjected to a cold drawing process with a working degree of 65%, followed by a heat treatment at 450 ° C. for 1 hour. Finally, the electrode wire 5 is passed through a plurality of wire drawing dies and subjected to diameter reduction processing at a processing degree of 99% to produce an electrode wire having a wire diameter of 0.25 mm.

  That is, Comparative Example 9 is the same as Example 1 except that the condition of the third diameter reduction step is a working degree of 99%. Therefore, the degree of processing in the third diameter reduction step exceeds the condition of the present invention.

(Conventional example 1)
An electrode wire having only a Cu-35Zn alloy wire and having a wire diameter of 0.25 mm is manufactured.

  Table 1 summarizes the manufacturing method, conditions and evaluation of the electrode wire of each example. That is, from the left, Table 1 shows the number of each example, the composition of the core material, the diffusion heat treatment conditions (conditions of the first heat treatment step), the degree of processing of intermediate wire drawing (conditions of the second diameter reduction step), the heat treatment conditions (first 2 heat treatment step conditions), final wire drawing degree (third diameter reducing step condition), wire drawing workability, electric discharge machining speed.

  Among the evaluations, the wire drawing workability was evaluated by the wire drawing weight (kg / time) until the wire was broken once, which was measured when wire drawing was performed to a predetermined size.

  The wire drawing weight is an amount measured when the coated wire 1 or the electrode wire 5 is drawn from a diameter before a predetermined drawing to a predetermined target diameter. The value divided by the number of disconnections during that time. Accordingly, the wire drawing weight represents the product weight per disconnection. It can be said that the wire drawing weight is superior in wire drawing workability. In Table 1, the drawing weight of the electrode wire of each example was evaluated in three stages. That is, an evaluation of round (good) was given if it was 100 kg / time or more, an evaluation of triangle (ordinary) if it was 50 to 100 kg / time, and an evaluation of bad (impossible) if it was 50 kg or less.

  Regarding the electric discharge machining speed, the electric discharge machining speed in each example was measured, and the measurement result was shown as an index when the conventional example 1 was set to 1.0. This index is calculated by dividing the electric discharge machining speed in each example by the electric discharge machining speed in Conventional Example 1, and the larger one is superior. However, the electrical discharge machining speed was not measured for the case where the wire weight could not be evaluated.

  Now, according to Table 1, it can be seen that the electrode wires of Examples 1 to 4 have an electrical discharge machining speed 30 to 40 points higher than that of Conventional Example 1. Moreover, it turns out that the electrode wire of Examples 1-4 has favorable wire drawing workability similarly to the prior art example 1. FIG.

  On the other hand, in Comparative Example 1, since the diffusion temperature (heat treatment temperature in the first heat treatment step) is low, Zn cannot be diffused, and as a result, the wire drawing workability in the third diameter reduction step is significantly reduced. , Could not be subjected to electric discharge machining.

  In Comparative Example 2, since the diffusion time (the heat treatment time in the first heat treatment step) is short, Zn does not diffuse uniformly, and as a result, the wire drawing workability in the third diameter reduction step is remarkably deteriorated. Could not be processed.

  Since Comparative Example 3 has a long diffusion time and Comparative Example 4 has a high diffusion temperature, the Zn concentration of the Cu—Zn diffusion layer 6 is lower than desired in all cases, and a great improvement in the electric discharge machining speed is recognized. I can't.

  In Comparative Examples 5 to 10, the degree of intermediate wire drawing (second reduction step condition), heat treatment condition (second heat treatment step condition), and final wire drawing degree (third diameter reduction step condition) are appropriate. Therefore, no breakage occurs at the time of wire drawing, and no significant improvement is observed in the electric discharge machining speed.

  From the above evaluation, it can be concluded that the present invention has an effect of producing an electrode wire having a high electric discharge machining speed with high productivity (low cost).

It is sectional drawing of the covering wire in the middle of manufacture which shows one Embodiment of this invention. It is sectional drawing of the covering wire in the middle of manufacture which shows one Embodiment of this invention, and the electrode wire of a finished product.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Coated wire 2 Wire drawing 3 Zn layer 4 Cu-Zn layer 5 Electrode wire 6 Cu-Zn diffusion layer

Claims (7)

A first coating step of coating a Zn layer on the outer periphery of a core material made of Cu or Cu alloy, and a second coating step of forming a coated wire by coating a low Zn concentration Cu-Zn layer on the outer periphery of the Zn layer; A first diameter reducing step for reducing the diameter of the coated wire , and heat treatment at 500 to 700 ° C. for 1 to 5 hours to diffuse Zn in the Zn layer into the Cu—Zn layer. A first heat treatment step for forming a Cu-Zn diffusion layer having a high Zn concentration, a second diameter reduction step for reducing the diameter of the coated wire, and a heat treatment for 0.5 to 2 hours at 450 ° C. on the coated wire after the heat treatment A wire comprising: a second heat treatment step for softening the coated wire by applying a wire; and a third diameter reducing step for imparting a desired tensile strength to the coated wire by reducing the diameter of the coated wire. Electrode for electrical discharge machining The method of production.   2. The method of manufacturing an electrode wire for wire electric discharge machining according to claim 1, wherein in the first diameter reduction step, the diameter reduction processing is performed so that the degree of processing of the Cu—Zn layer is 50 to 80%. 3. The method of manufacturing an electrode wire for wire electric discharge machining according to claim 1, wherein the second diameter reduction step performs diameter reduction processing so that a degree of processing of the Cu—Zn diffusion layer is 50 to 80%. Method. 4. The wire electric discharge machining electrode wire according to claim 1, wherein in the third diameter reduction step, the diameter reduction processing is performed so that the processing degree of the Cu—Zn diffusion layer is 70 to 98%. Production method. In the first covering step, a Zn layer is coated by vertically attaching a Zn tape to the outer periphery of the core material, and in the second covering step, a Cu-Zn tape is vertically attached to the outer periphery of the Zn layer. The manufacturing method of the electrode wire for wire electric discharge machining in any one of Claims 1-4 . The said core material is Cu-0.10-0.70weight% In alloy , The manufacturing method of the electrode wire for wire electric discharge machining in any one of Claims 1-5 characterized by the above-mentioned. The method of manufacturing an electrode wire for wire electric discharge machining according to any one of claims 1 to 6 , wherein the first heat treatment step has a Zn concentration in the Cu-Zn diffusion layer of 38 to 50 wt% after the heat treatment.

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