JPH0413046B2 - - Google Patents

Description

[Detailed description of the invention]

TECHNICAL FIELD OF THE INVENTION The present invention relates to a continuous wire drawing method for cold forging wire rods, in which the wire rods (including steel bars) are continuously moved and subjected to descaling, lubrication base treatment, and lubrication treatment before being drawn. Conventional technology and its problems The secondary processing of wire rods for cold forging consists of wire rod descaling (pickling) - lubrication surface treatment - lubrication treatment -
Drying, wire drawing, and winding are performed in this order. Pickling, lubrication base treatment, and lubrication treatment are generally performed in a batch process. That is, conventionally, after pickling a wire, it is immersed in a phosphate solution such as zinc phosphate, and then immersed in an aqueous solution such as sodium stearate to coat the surface of the wire with zinc stearate,
This method forms a lubricating film such as zinc phosphate. Conventionally, this batch treatment method has been adopted because it takes a long reaction time to obtain a film thick enough to exhibit sufficient lubrication performance, and to do so, the treatment tank must be made longer. can be,
This is due to reasons such as difficulty in going online. Therefore, for example, in Japanese Patent Application Laid-Open No. 56-163047,
With the aim of improving equipment costs and productivity, a method has been proposed that allows lubrication base treatment and lubrication treatment to be performed online, and has already been put into practical use. This method is characterized by attaching calcium stearate at room temperature (lubrication treatment) to the surface of the wire rod, which has been descaled and treated with zinc phosphate coating (lubrication base treatment), followed by rapid drying, resulting in running costs. In addition, the required amount of lubricant can be deposited in a short time, and drying can be completed in a short time, making it possible to go online without significantly extending the line. However, the conventional method uses the batch processing method described above,
In both online methods, a zinc phosphate solution is used as a lubricating base agent, which has the drawback of poor heat resistance of the lubricating film. Purpose of the Invention This invention brings wire rod descaling, lubrication base treatment, lubrication treatment, drying, and wire drawing processing online, obtains a lubricating film with excellent heat resistance, and makes wire drawing more efficient and shorter than ever before. The purpose of this paper is to propose a continuous wire drawing method that can be carried out in a short period of time. Structure of the Invention In the continuous wire drawing method according to the present invention, a preheated wire after descaling is heated at 70 to 90°C and subjected to ultrasonic waves (frequency: 10 to 60 KHz, output: 25 W/solution 1).
Lubricating base treatment is performed by passing the wire through a zinc calcium phosphate solution (Ca/Zn = 0.3 to 0.5) to which a base-treated wire has been added (Ca/Zn = 0.3 to 0.5), and after washing with water, calcium stearate is attached to the base-treated wire at room temperature, or the wire is Lubricating treatment is carried out through a sodium stearate solution kept at ~90℃, and after drying, when drawing the wire, 1 to 10% by weight of thermoplastic is added to a lubricant mainly consisting of metal soap as a lubricant before the die. It is characterized by adding a resin (for example, fluororesin, polyethylene, nylon, acrylic, polycarbonate, etc.). This invention will be explained in detail below. First, the method for descaling the wire in the present invention is not particularly limited, and may be any of pickling, shot blasting, and roll bending. Among these, the shot blasting method is suitable for online production in order to secure a phosphate film. Next, as a lubricating surface treatment agent, this invention uses a zinc calcium phosphate solution (Ca/
It is characterized by using Zn=0.3 to 0.5). That is, the decrystallization water temperature for the zinc phosphate calcium film is 415°C, whereas the decrystallization water temperature for the conventionally used zinc phosphate film is 280 to 290°C. Therefore, the zinc phosphate film turns into decrystallized water due to heat generation (200 to 300°C) during wire drawing. For this reason, cracks tend to occur in the coating during wire drawing. On the other hand, in the zinc calcium phosphate coating of the present invention, since the decrystallization water temperature is 415° C. as described above, the coating does not crack due to wire drawing. Further, the present invention is characterized in that ultrasonic treatment is carried out in order to ensure the amount of adhesion of the zinc calcium phosphate film and to control the amount of adhesion. This is because zinc calcium phosphate solution has a slightly poorer chemical conversion treatment property than zinc phosphate solution, so it is difficult to secure a sufficient amount of adhesion. However, as shown in Figure 1, which shows the effect of ultrasonic waves, adding ultrasonic waves to the zinc calcium phosphate solution increases the amount of adhesion, so a method of adding ultrasonic waves to the lubricating base treatment was adopted. The results shown in Figure 1 are based on the concentration as the processing condition.
340g/, temperature 80℃, ultrasonic frequency 50KHz,
This is the case of 1KW. In addition, the above ultrasonic frequency is 10 to
60KHz is preferable. This is because below 10KHz there is a problem in terms of noise, and above 60KHz there is not much effect on the amount of adhesion. Further, the output power is preferably 25 W per solution. The reason for this is that an experiment was conducted using ultrasonic waves with an output of 1 KW and in a treatment tank for the solution 401, and a predetermined amount of zinc phosphate coating could be obtained. In addition, the Ca/calcium zinc phosphate film mentioned above
The reason why the Zn ratio was set to 0.3 to 0.5 is as follows. FIG. 3 is a chart showing the relationship between the Ca/Zn ratio and the amount of adhesion in a zinc calcium phosphate film (solution concentration 340 g/). That is, when the Ca/Zn ratio is less than 0.3, the effect of adding Ca is small because the ratio of Ca is small, and the heat resistance is not sufficient. Also, Ca/Zn＞
In the case of 0.5, chemical conversion treatment is poor and the specified phosphate adhesion amount (≧6g/m ² ) and metal soap adhesion amount (≧1
g/m ² ) is difficult to obtain. Therefore, the Ca/Zn ratio of the zinc calcium phosphate film is preferably 0.3 to 0.5. In addition, the concentration of zinc calcium phosphate solution is 340
If it is not more than 6 g/m 2 , it will not be possible to obtain a predetermined adhesion amount of 6 g/m ² or more in a short time treatment of 10 to 20 seconds. Moreover, if it exceeds 425 g/g, it is not economical because the amount of adhesion cannot be obtained even though the concentration is increased. Here, the predetermined adhesion amount of the zinc phosphate calcium film is set to 6 g/m2 ^or more because conventional zinc phosphate films have poor heat resistance, so the predetermined adhesion amount is set at 7 to 8 g/m2.
m ² , but in the case of the zinc calcium phosphate film of the present invention, 6 g/m ² is sufficient because it has excellent heat resistance. The lubrication treatment performed after the above-mentioned lubrication base treatment is a method of depositing calcium stearate at room temperature,
Alternatively, it is characterized by passing it through a sodium stearate solution kept at a temperature of 70 to 90°C. In the case of calcium stearate treatment,
As is clear from the relationship between the concentration and the amount of adhesion shown in FIG. 4, the concentration is set to 300 g/m or more in order to keep the amount of adhesion at the predetermined value of 5 g/m ^{2 or} more. In addition, the method for attaching calcium stearate to the wire is as follows:
A wet spray method (coating a solution) or a dry coating method (coating a powder) can be employed, but application by a wet spray method is preferable in view of the amount of lubricant deposited, the adhesion of the film, etc. Note that the processing time is usually about 2 to 3 seconds due to physical adhesion. In addition, in the case of sodium stearate treatment, a batch method can be adopted, but in this case, a reaction layer (stearate Zinc) will adhere to the surface. The amount of the reaction layer deposited must normally be 1 g/m ² or more, and the treatment time required for this purpose is 20 seconds or more based on the relationship between the sodium stearate treatment time and the amount of reaction layer deposited as shown in FIG. Note that the above lubrication treatment can be omitted if a pre-die lubricant is added during wire drawing. In this invention, the pre-die lubricant is added during wire drawing in order to further improve the heat resistance and lubricity of the lubricant film. 1 to 10
A material containing a thermoplastic resin (for example, fluororesin, polyethylene, nylon, acrylic, polycarbonate, etc.) in an amount of % by weight is used. The reason why thermoplastic resins are added to lubricants for metal soaps is to take advantage of the heat resistance and low friction properties of thermoplastic resins, such as fluorocarbon resins. Also, the amount added is 1
The reason for limiting the amount to ~10% by weight is that if it is less than 1%, the addition will not have much of an effect on the pulling force, etc. On the other hand, as the amount added increases, the effect will be obtained, but it will be Being an elementary gas,
Also, taking into account costs, the upper limit was set at 10%. FIG. 6 is a block diagram showing the processing steps of the present invention. That is, the wire is unwound from a payoff stand 1 and descaled in a descaling step 2 by, for example, shot blasting. Subsequently, a zinc calcium phosphate solution (Ca/Zn=0.3 to 0.5) is preheated to a predetermined temperature (80°C or higher) in a preheating device 3 and then subjected to ultrasonic waves in a lubrication base treatment step 4.
Lubricating base treatment is carried out through the inside. The zinc calcium phosphate solution is preheated to a temperature of 70-90 °C. Next, after passing through a water washing step 5, in a lubrication treatment step 6, calcium stearate or sodium stearate is applied to the wire rod which has been subjected to the lubrication base treatment, and is then subjected to a lubrication treatment. Calcium stearate treatment is carried out at room temperature, in the case of sodium stearate the solution is preheated to a temperature of 70-90°C. After this lubrication treatment, the wire rod is dried in a drying step 7 to sufficiently dry the lubricating film, and then in a wire drawing step 8 a pre-dice lubricant is added, the wire is drawn, and the wire is wound up in a winding device 9 . Here, as a device for performing ultrasonic lubrication base treatment, as shown in FIGS. 7 and 8, for example, a plurality of ultrasonic application devices 12 are installed on the outer peripheral surface of a cylindrical treatment tank 11 in the vertical and horizontal directions. Two locations are placed parallel to each other (of course, the positions may be shifted from each other), and the processing liquid is passed through the return pipe 14 from the processing liquid receiver 13 protruding from the inlet and outlet sides of the processing tank 11. It is possible to use a structure in which a liquid tank 15 is provided to collect the processing liquid 19, and a pipe 17 is provided so that the processing liquid in the processing liquid tank 15 is circulated and supplied to the processing tank 11 by a pump 16. According to such a device, ultrasonic waves are irradiated into the zinc calcium phosphate solution to stir the solution, and the zinc calcium phosphate solution quickly adheres to the surface of the wire 18 due to the cavitation action. Also,
The amount of deposited zinc calcium phosphate solution can be controlled by changing the presence or absence of ultrasonic wave application or the frequency of the ultrasonic wave application device. Example With the line configuration shown in Figure 6, shot blasting was used to descale the wire rod, and the line configuration shown in Figures 7 and 8 was used.
Using equipment equipped with the ultrasonic lubrication surface treatment equipment shown in the figure, 5.5 mmφ material (material S45C) is drawn under the operating conditions shown below, resulting in wire drawings of 4.95 mmφ and 4.6 mmφ.
A drawn wire material was obtained. Operating conditions Descaling conditions Abrasive material: Steel balls with a diameter of 0.3 mm, projection density: Approx. 300
Kg/m ² Preheating conditions Steam spraying: Preheating temperature 80℃ Lubrication base treatment conditions Lubrication base agent: Zinc calcium phosphate solution (Ca/Zn=0.5) Adhesion conditions: 340g/(concentration) x 80℃ (temperature)
×15sec (reaction time), ultrasonic wave: 50KHz. 1KW
(Solution volume 160) Lubrication treatment conditions () For calcium stearate Concentration: 300g/, Temperature: Room temperature, Time: 3
Seconds () For sodium stearate Concentration: 90g/, Temperature: 80℃, Time: 25 seconds Drying treatment conditions Infrared drying oven: Furnace temperature 80℃ Wire drawing conditions Pre-die lubricant: Lubricant mainly composed of calcium stearate with 3% fluorine resin added Area reduction rate: approx. 19% (5.5mmφ→4.95mmφ) Approx. 30% (5.5mmφ→4.6mmφ) Wire drawing speed: 80m/min Table 1 shows the results during wire drawing This figure shows a comparison of the pullout force of 200 mm with that of the conventional method (lubricating base treatment: zinc phosphate, pre-die lubrication: only a commercially available lubricant whose main component is calcium stearate). In addition, the Bauden test (lubrication ability,
The results of the oil film adhesion investigation are shown in Figure 9, μ=
Table 2 shows the number of Bauden sliding operations that reach 0.2 in comparison with the conventional method. In addition, the conditions of Invention Example 1 (however, the wire drawing area reduction rate:
Table 3 shows a comparison of the lifespan of the wire drawing die and cold forging die when wire is drawn at 5.5φ→4.95φ) and machine screws are manufactured by cold forging compared to conventional ones.

【table】

【table】

[Table] However, the lifespan of dies and molds is due to wear and tear.
Manufacturing up to the replacement of dies and molds due to defects etc.
From Tables 1 and 2 and FIG. 9, it can be seen that the lubricating film according to the present invention has better heat resistance and adhesion than the conventional zinc phosphate film. Therefore, as is clear from Table 3, the life of wire drawing dies and cold forging dies is also significantly extended. Effects of the Invention As explained above, by using zinc calcium phosphate as a lubricating base treatment agent, the method of this invention can provide a film with a higher decrystallization water temperature and superior heat resistance than the conventional zinc phosphate film. By employing ultrasonic wave applying means, it is possible to freely secure and control the adhesion amount of the zinc calcium phosphate film. Furthermore, calcium stearate is added on top of the above lubricating base treatment agent.
Alternatively, lubrication treatment with sodium stearate has the effect of improving not only heat resistance but also lubricity. In addition, by using a lubricant in front of the die during wire drawing, which is a mixture of conventional lubricants mainly based on metal soaps and thermoplastic resins such as fluorine-based resins, the heat resistance of the lubricating film and the lubrication This has the effect of further increasing the properties and significantly extending the life of cold working tools.

[Brief explanation of drawings]

Figure 1 is a diagram showing the effect of ultrasonic application in the lubricating base treatment of the present invention, Figure 2 is a diagram showing the relationship between the ultrasonic frequency and the amount of zinc calcium phosphate deposited in the same as above, and Figure 3 is a diagram showing the relationship between the ultrasonic frequency and the amount of zinc calcium phosphate deposited in the same as above. A chart showing the relationship between the Ca/Zn ratio and the amount of adhesion in the calcium oxide film, Figure 4 is a chart showing the relationship between the concentration of calcium stearate and the amount of adhesion in the above, and Figure 5 shows the relationship between the treatment time and the amount of sodium stearate in the same as above. FIG. 6 is a block diagram showing the processing steps of the present invention; FIG. 7 is a schematic side view showing an example of the apparatus for performing the ultrasonic lubrication base treatment in the same manner; FIG. The figure is a schematic front view showing the processing tank of the same apparatus as above, and FIG. 9 is a chart showing the Bowden test results in an example of the present invention. 1... Payoff reel, 2... Descaling process, 3... Preheating process, 4... Lubrication base treatment process,
5... Water washing process, 6... Lubrication treatment process, 7... Drying process, 8... Wire drawing process, 9... Winding device, 11
...Processing tank, 12...Ultrasonic addition device, 13...
Processing liquid receiver, 14... Return pipe, 15... Processing liquid tank, 18... Wire rod, 19... Processing liquid.

Claims (1)

[Claims] 1 Descaling while continuously moving the wire,
In the method of drawing wire after applying lubrication treatment and lubrication treatment, the wire rod that has been preheated after descaling is kept at a temperature of 70 to 90 degrees Celsius, and ultrasonic waves (frequency: 10 to 60 KHz, output: 25 W/per solution) are applied. A lubrication base treatment was performed by passing the wire rod through a zinc calcium phosphate solution (Ca/Zn = 0.3 to 0.5), and after washing with water, the wire rod subjected to the base treatment was placed in a calcium stearate solution kept at room temperature or kept at a temperature of 70 to 90 °C. It is characterized by adding 1 to 10% by weight of a thermoplastic resin to a lubricant mainly made of metal soap as a lubricant before the die when it is passed through a sodium stearate solution for lubrication treatment and then drawn after drying. Continuous wire drawing method for wire rods.