JPH0585241B2 - - Google Patents

Description

[Detailed description of the invention]

INDUSTRIAL APPLICATION FIELD The present invention relates to a pinch roll for taking off copper wire used in continuous rolling equipment for copper wire and a method for manufacturing copper wire using the pinch roll. Conventional technology Conventionally, the surface of pinch rolls used for continuous rolling of copper rough drawing wire, etc., has been roughened by surface treatments such as shot blasting in order to increase the coefficient of friction and improve the gripping ability of the rough drawing wire. It is formed. Further, this pinch roll was made of hardened tool steel in order to prevent the unevenness of the pinch roll surface from decreasing due to wear and the accompanying deterioration of the ability to grip the rough wire. Problems to be Solved by the Invention However, tool steel that has been quenched to increase its hardness and chromium (Cr) on the surface of the pinch roll.
If a pinch roll is used that has an alloy containing molybdenum (Mo) or a chrome plating layer to increase the hardness of the surface, the steel tends to adhere to the roll surface, so the rough copper wire is scraped off when the roll is taken off. The resulting copper powder is embedded in the concavities and convexities on the pinch roll surface and adheres, causing clogging.As a result, the concavities and convexities on the roll surface are reduced, and the friction coefficient of the roll surface against the copper roughening wire is reduced. Put it away.
In such a state, the ability of the pinch rolls to grip the rough drawing line deteriorates, making it impossible to take off the rough drawing line at a speed equal to the linear speed of the rough drawing line coming out of the final stand of the rolling mill, and as a result, the final roll exits. There is a problem in that a buckling phenomenon called cobble occurs and the rolling process stops. Therefore, in order to prevent copper powder etc. from becoming embedded in the recesses of the pinch roll surface irregularities and adhering to them, reducing the coefficient of friction, a powerful shot blasting treatment is performed to greatly increase the roughness of the surface irregularities. If a pinch roll is used, the convex parts of the uneven surface will chip off, and
This not only reduces the gripping force of the pinch rolls on the copper wire, but also causes the problem that chipped iron particles become embedded in the surface of the wire as foreign iron particles. There is a problem in that the rough drawn wire in which iron foreign matter is embedded in this way is likely to break when it is thinned and drawn to about three times the size of the iron foreign matter. The present invention has been made in view of the above circumstances, and it is possible to reduce the occurrence of buckling phenomenon called cobble due to insufficient gripping force of the pinch rolls in the drawing process of copper rough drawing wire, and to maintain a stable coefficient of friction for a long period of time. To provide a pinch roll for copper rough drawing wire which has wear resistance and which does not cause iron foreign matter to be embedded in the copper rough drawing wire due to wear and tear, causing wire breakage or quality deterioration in the wire drawing process. The purpose of the present invention is to provide a method for manufacturing rough drawn copper wire using pinch rolls. Means for Solving the Problems The invention of claim 1 of the present application specifies a pinch roll for copper rough drawing wire, and its characteristics are as follows:
A pinch roll for copper rough drawing wire that pulls copper rough drawing wire in the presence of a weakly acidic medium, and has a carbon content of
Using 0.25-0.75% by weight carbon steel as the roll material,
The surface is hardened to a hardness of at least H _R C50 or higher, and the surface is treated to a roughness of 10 μm to 50 μm. The invention of claim 2 also relates to a pinch roll for copper rough drawing wire, and the feature is that in the pinch roll for copper rough drawing wire of claim 1, the weakly acidic medium is isopropyl alcohol and its decomposition product. The reason is that it is an aqueous solution of a substance. Furthermore, the invention of claim 3 relates to a method for producing copper wire, which is characterized in that in the rolling process of the copper wire, after the copper wire is treated with a weakly acidic medium, the carbon content is reduced to 0.25. ~0.75% by weight carbon steel is used as the material, and the surface is hardened to a hardness of at least H _R C50 or higher, with a surface area of 10μm to 50μm.
Copper rough drawing wire pinch rolls are used to remove the wire. Furthermore, the invention of claim 4 also relates to a method for manufacturing copper rough drawn wire, and the feature thereof is as follows.
In the method, the treatment with the weakly acidic medium is cooling of the copper wire and descaling with a reducing agent. The invention of claim 5 also relates to a method for producing copper wire, and the feature is that in the method of claim 3 or 4, the weakly acidic medium is isopropyl alcohol and its decomposition product. The reason is that it is an aqueous solution of The configurations that are common to each invention of the present application and are fundamentally important in the invention of the present application as described above are: a: Regarding the pinch roll for taking off the copper rough drawing wire in the rolling process of the copper rough drawing wire, b: The usage environment is weakly acidic. C: As roll material, carbon content is 0.25-0.70
d: The hardness of the roll surface is H _R C50 or higher; e: The surface roughness is within the range of 10 to 50 μm. Points a to e above. With such a configuration, it has become possible to solve the above-mentioned problems. Function The pinch roll of the present invention uses carbon steel with a carbon content of 0.25 to 0.70% by weight as its material. Here, as is well known to those skilled in the art, carbon steel is a Fe-C steel to which alloying elements are not actively added. Such carbon steel has lower corrosion resistance than alloy steels such as tool steels. Therefore, when taking off relatively high-temperature copper wire after hot rolling that has been treated with a slightly acidic medium, the roll surface is corroded at a moderate temperature by this medium, and the copper wire is scraped off. This prevents the copper powder from adhering to the recesses on the roll surface and clogging the surface unevenness. Also,
Corrosion pits are formed by this high-temperature corrosion, thereby maintaining the unevenness of the roll surface. moreover,
Since the H _R C50 or more is set, the wear rate of the convex portions of the pinch roll surface irregularities is reduced, and the rate of decrease in the coefficient of friction of the pinch roll surface with respect to the rough drawing line is also reduced accordingly. As a result, the pinch roll's gripping force on the rough line is less likely to decrease, and problems such as cobble, etc., do not occur, and the life of the roll is extended. In other words, it takes longer to replace the pinch roll. In addition, the surface of the pinch roll is treated with a shot blasting process that creates unevenness with a roughness of 10 μm or more, so it can grip copper rough wire etc. reliably without insufficient frictional force at the start of operation. I can do it. Furthermore, since the surface roughness resulting from shot blasting is less than 50 μm, there is no possibility of iron foreign matter occurring due to chipping of the convex portions of the surface roughness, and there is little risk of wire breakage or quality deterioration in the subsequent wire drawing process. Hereinafter, the pinch roll of the present invention will be explained in detail. The pinch roll of the present invention uses carbon steel with a carbon content of 0.25 to 0.70% by weight as the roll material, and is hardened so that the surface hardness of the pinch roll becomes H _R C50 or more. The surface has been subjected to surface treatment such as shot blasting so that the surface roughness is 10 μm to 50 μm. In the pinch roll for copper rough drawing wire of the present invention, carbon steel with a carbon content within a certain range was selected as the roll material instead of alloy steel such as tool steel.By using such carbon steel, weakly acidic When pulling relatively high-temperature copper rough drawn wire treated with this medium, the roll surface is moderately corroded in the presence of this slightly acidic medium, and the above-mentioned effects such as preventing clogging and maintaining the coefficient of friction are achieved. Because it plays. Here, if the carbon content of the carbon steel is less than 0.25% by weight, it will not have enough hardness even after quenching, and if it exceeds 0.70% by weight, the convex parts of the surface unevenness will wear out quickly and the pinch roll will be damaged in a short time. The coefficient of friction of the surface decreases, making it easier to cause a buckling phenomenon called cobble. Also, if the hardness of the surface is less than H _R C50, the surface will wear quickly and cause problems in a short period of time. Here, the quenching hardness of the pinch roll surface can be adjusted by changing the carbon content and quenching conditions. In addition, in the pinch roll of the present invention, if the surface roughness is less than 10 μm, the friction coefficient of the surface will be low and the gripping force of the rough drawing line will be insufficient, and a buckling phenomenon called cobble will easily occur at the start of operation. but
If it exceeds 50 μm, the convex portions of the surface irregularities are likely to be damaged, and iron foreign matter will be mixed into the surface of the rough drawn wire, causing problems such as reduced wire drawability. This surface roughness is imparted using a general-purpose shot blasting machine, and the surface roughness can be adjusted by selecting the shot conditions of this shot blasting machine. Next, a method for manufacturing rough drawn copper wire according to the present invention using such a pinch roll will be described. A feature of the manufacturing method of the present invention is that the copper wire is treated using a weakly acidic medium before the copper wire is taken off with pinch rolls. This process is
This is for cooling the copper rough drawing wire during hot rolling and for descaling using a reducing agent. As the weakly acidic medium, an aqueous solution of an alcohol having 1 to 4 carbon atoms and its decomposition product is preferred, and an aqueous solution of isopropyl alcohol and its decomposition product is particularly preferred. Alternatively, an aqueous solution of an organic acid such as a carboxylic acid having 1 to 4 carbon atoms may be used. The pH of the weakly acidic medium is preferably about 4 to 6. If the pH is less than 4, the carbon steel surface will corrode at too high a temperature, making it easy to lose the convex and convex portions of the roll surface, resulting in a decrease in frictional force and insufficient gripping force, making long-term operation impossible. This is because, if the pH is higher than 6, high-temperature corrosion on the carbon steel surface is insufficient, and the effects of the present invention, such as preventing clogging due to adhesion of copper powder, etc., cannot be obtained. In the present invention, the effect is exhibited by removing the weakly acidic medium remaining on the rough drawing line using pinch rolls. In other words, when using pinch rolls, the copper wire is still relatively hot just after hot rolling, and the interface temperature rises due to friction between the pinch roll and the copper wire, causing the pinch roll surface to heat up. The temperature will be quite high. Here, when the above-mentioned weakly acidic medium and carbon steel with a carbon content of 0.25 to 0.70% by weight come into contact at this high temperature, the roll surface undergoes moderate high-temperature corrosion, resulting in the formation of this corrosion film and destruction. It is estimated that repeated use prevents clogging caused by the scraped copper adhering to the recesses of the surface unevenness, and also maintains a suitable level of unevenness due to the formation of corrosion pits at high temperatures, which prevents a decrease in the coefficient of friction. be done. In addition, if rolling is performed using the roll of the present invention while supplying an aqueous solution of about 2% isopropyl alcohol and its decomposition products as a medium to the rolling material, continuous operation for several tens of hours is possible. Ta. In this regard, conventional rolls made of highly alloyed materials such as SKD11 could become unusable after several hours of continuous operation. The rough wire to which this weakly acidic medium has adhered is subjected to neutralization and anti-corrosion treatment, then wound up by a winder and sent to a subsequent process. Examples Examples and comparative examples of the present invention are shown in Table 1.

[Table] The Examples and Comparative Examples shown in Table 1 show the occurrence of various defects when the pinch rolls of the Examples and Comparative Examples of the present invention were used as the final take-off pinch rolls in continuous rolling of copper. . In each of the Examples and Comparative Examples, an aqueous solution of about 2% isopropyl alcohol and its decomposition products was heated to various pH levels immediately before the copper wire was taken off with a pinch roll.
Cooling treatment was carried out using a medium adjusted to as a cooling treatment liquid. In Table 1, the term "failure at the start" indicates whether or not a buckling phenomenon called cobble occurred immediately after starting the work. Further, the continuous operation time refers to the time from the start of work until the occurrence of cobble, and when it is 5 hours or more, it is marked as ○, and when it is less than 5 hours, it is marked as ×.
Regarding product quality, if the product 50 μm conductor wire can be drawn to 300 kg without wire breakage, it is rated as 〇, and if it is less than 300 kg, it is rated as ×. As is clear from Table 1, a pinch roll made of carbon steel within the carbon content range of the present invention and whose surface hardness and surface roughness were adjusted within the range of the present invention was used, and the PH was used as the cooling treatment liquid. In Examples 1 and 2, in which weak acids within the range of 4 to 6 were used, good results were obtained in terms of problems at the start of work, continuous operation time, and product quality. On the other hand, in the case of Comparative Example 1, the continuous operation time was shortened because the surface hardness of the pinch roll was low, and in the case of Comparative Example 2, the surface roughness of the pinch roll was small, so there was a problem at the start of work. Furthermore, the continuous operation time has become shorter. Furthermore, in the case of Comparative Example 3, the carbon content of the pinch roll was too high and the friction coefficient necessary to enable continuous operation could not be maintained, resulting in a short continuous operation time. Further, in the case of Comparative Example 4, the surface roughness of the pinch roll was large and the surface irregularities were too large, so the tips of the convex portions were chipped and embedded in the copper rough drawing wire, resulting in poor product quality. Furthermore, Comparative Example 5 is a pinch roll made of conventional tool steel of SKD11, and Comparative Example 6 is a pinch roll made of SKD11 tool steel.
Comparative Example 7 uses a pinch roll with the composition disclosed in the Japanese Patent Publication No. 48-40623, and these pinch rolls have good corrosion resistance and resistance. They are made of alloyed steel with alloying elements added to make them wear-resistant alloys, and when these were used, the continuous operation time was shortened. Furthermore, in Comparative Example 8, a pinch roll having the same composition, surface hardness, and surface roughness as in Example 1 was used, but since the pH of the cooling treatment liquid was kept neutral at 7, the roll surface was moderate. As a result, continuous operation time was shortened. Effects of the Invention The pinch roll for copper rough drawing wire of the invention of claims 1 and 2 is a pinch roll for copper rough drawing wire that pulls copper rough drawing wire in the presence of a weakly acidic medium, and has a carbon content of 0.25 to 0.25. Since 0.70% by weight carbon steel is used as the roll material, the roll surface is corroded at moderately high temperatures in the presence of a weakly acidic medium, which prevents clogging of the concave portions of the roll surface and maintains an appropriate coefficient of friction. can be retained. In addition, since the hardness is H _R C50 or higher, there is little wear on the surface irregularities and long-term operation is possible. In addition, the pinch roll surface has been subjected to a surface treatment such as shot blasting to a roughness of 10 μm to 50 μm, so that the rough wire gripping force at the start of operation is appropriate and high without embedding iron foreign matter on the rough wire surface. It has the advantage of being able to process high-quality products continuously. Further, according to the method for manufacturing copper rough drawing wire of the invention according to claims 3 to 5, by actually using the pinch rolls as described above in the rolling process of copper rough drawing wire, it is possible to lengthen the time for changing the rolls. As a result, the quality of the product can be improved, and furthermore, the working efficiency and yield can be improved.

Claims (1)

[Scope of Claims] 1. A pinch roll for copper rough drawing wire for drawing copper rough drawing wire in the presence of a weakly acidic medium, which uses carbon steel with a carbon content of 0.25 to 0.75% by weight as the roll material, and comprises at least A pinch roll for copper rough drawing wire characterized by having a surface hardened to a hardness of H _R C50 or higher and a surface treatment to a roughness of 10 μm to 50 μm. 2. The pinch roll for copper rough drawing wire according to claim 1, wherein the weakly acidic medium is an aqueous solution of isopropyl alcohol and its decomposition products. 3 In the rolling process of copper rough drawing wire, after treating the copper rough drawing wire with a weakly acidic medium, the carbon content is reduced to 0.25.
~0.75% by weight carbon steel is used as the material, the surface is hardened to a hardness of at least H _R C50 or higher, and the surface is treated with a roughness of 10μm to 50μm.Pinch rolls for copper rough drawing wire are used to remove the wire. A method for manufacturing copper rough wire, characterized by the following. 4. The method for producing copper wire according to claim 3, wherein the treatment with the weakly acidic medium includes cooling the copper wire and descaling using a reducing agent. 5. The method for producing copper wire according to claim 3 or 4, wherein the weakly acidic medium is an aqueous solution of isopropyl alcohol and its decomposition products.