JPH0699797B2 - Method for plating thermal diffusion alloy on rubber-reinforced wire - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention continuously deposits two or more different metals on a linear body.
The present invention relates to a method for plating a thermal diffusion alloy on a rubber-reinforcing linear body, which comprises plating in a multilayer structure of at least one layer and then performing thermal diffusion alloy plating by thermal diffusion.

(Prior art and its problem) Conventionally, when a linear body is continuously alloy-plated with two or more kinds of metals, heat diffusion is performed on the linear body in a plating bath containing an alloy metal component of interest at the same time. Instead, the alloy is plated as an alloy, or a metal serving as an alloy component is sequentially plated in layers, and then heat diffusion treatment is performed to perform alloy plating.

And the thickness of the alloy plated on such a linear body,
Alternatively, various studies have been made to analyze the alloy composition ratio nondestructively during the production process and feed it back to the process in real time based on the result to automatically control the plating current etc. to improve the plating quality accuracy.

For example, in alloy plating by simultaneous electrodeposition as disclosed in Japanese Patent Laid-Open No. 54-29843, a method for nondestructive and accurate analysis after complete alloy plating has been established. Although the application is also being investigated, in the alloy plating obtained by the thermal diffusion method like the latter, the plating alloy composition gradient peculiar to the thermal diffusion alloy plating method (the alloy composition ratio is from the inner layer portion of the plating layer to the intermediate layer portion, It is very difficult to obtain the target alloy plating with high accuracy and evenly in the longitudinal direction of the linear body, and it has not been put to practical use. Is the current situation.

Further, in recent years, due to pollution problems and the like, a method of performing alloy plating by thermal diffusion has been more often used than a method of performing alloy plating by simultaneous electrodeposition using a cyanide bath or the like.

By the way, particularly in a linear body used for rubber reinforcement such as an automobile tire or a conveyor belt, along with its strength, adhesiveness with rubber is required as the most important quality, and the precision required for this type of alloy plating is It is extremely severe.

That is, in the alloy plating on the linear body, the adhesion amount of the plating and the alloy composition ratio of the plating (for example, the weight ratio of Cu and Zn) are severely limited due to the influence of the adhesion to the rubber, and the value is the rubber. It changes slightly depending on the type.

In addition, in order to improve the adhesiveness with rubber, it is currently required that the alloy plating has a plating alloy composition gradient.

Furthermore, the above-mentioned composition gradient of the plating alloy affects not only the type of rubber but also the degree of influence of the same rubber depending on the usage state. For example, when used at a high temperature, the composition gradient of the plating alloy has a great influence. Therefore, the value of the composition gradient of the plating alloy must be adjusted in order to obtain the desired alloy plating depending on the type of rubber, the application, and the like.

Therefore, in order to obtain the desired plating alloy composition gradient uniformly,
Based on the idea of giving a predetermined amount of heat to the linear body and keeping the diffusion temperature of the linear body constant, a method of raising the temperature by Joule heat generation by directly supplying an electric current to the linear body, or in a diffusion furnace An indirect heating method by passing is used. However, even if a predetermined amount of heat is applied to obtain the desired plating alloy composition gradient, the temperature of the linear body itself does not rise to a predetermined temperature, or the plating alloy composition changes due to fluctuations in the heating amount or fluctuations in the temperature holding time. There was a problem that the inclination fluctuates significantly.

Further, in the conventional method, for various kinds of metal plating applied in layers, depending on the amount of heat for diffusion to be added thereafter,
Whether the alloy composition ratio is constant from the outermost part of the alloy plating to the inside to the vicinity of the plating base and it is in a single alloy phase state,
Although it is possible to make the composition ratio incline and make the phase states different, it was not possible to control this phase state and obtain it uniformly in the longitudinal direction of the linear body. Up to now, the degree of diffusion of thermal diffusion alloy plating of a linear body can be known by measuring the phase state of the alloy by an X-ray diffractometer, or by changing the composition ratio of the component metals of the alloy plating by instrumental analysis or chemical analysis. Is done by measuring. However, these measurement methods cannot be performed during continuous operation because the measurement samples are taken.

The object of the present invention is to control the plating alloy composition gradient, which varies from moment to moment, so that there is very little variation in the degree of diffusion, and the type of rubber, alloy plating with high precision according to the application, etc., in the longitudinal direction of the linear body. Another object of the present invention is to provide a thermal diffusion alloy plating method for a rubber-reinforcing linear body that can be applied almost uniformly.

(Means for Solving Problems) The present invention has been made to achieve the above object,
A continuous alloy plating method for a linear body, in which two or more different metals are continuously plated into two or more layers for each type of metal while the linear body is running In the above, the secondary X-rays are simultaneously detected from the respective metals subjected to the thermal diffusion alloy plating by the energy dispersive fluorescent X-ray analyzer arranged at a predetermined position before the thermal diffusion step, and the secondary X-ray intensity ratios are used to detect the secondary X-rays. Analyzing the plating alloy composition gradient of the metal, calculate a correction value by comparing the detected value and a preset reference value, continuously feed back the correction value to the diffusion heat quantity control unit of the heat diffusion device, It is made by automatically controlling the plating conditions.

Further, after the plating process is completed and before the thermal diffusion process, the secondary X-rays from the metals plated in layers are simultaneously detected by the energy dispersive fluorescent X-ray analysis device, and the secondary X-rays are detected. Analyze the metal adhesion amount ratio of each metal from the intensity ratio of the line, compare the detected value with a preset reference value to calculate the modification value, and use the modification value to disperse the energy-dispersed type placed after the thermal diffusion process. The correction value obtained by the fluorescent X-ray device may be corrected.

(Operation) A fluorescent X-ray measurement method is used to simultaneously detect the secondary X-rays of the alloyed plating component metals with an energy dispersive X-ray fluorescence analyzer and determine the plating alloy composition gradient from the respective intensity ratios. The secondary X-rays generated from the entire plating layer are not the same as the irradiation X-ray dose due to the characteristics of the above. The more secondary X-rays generated from the inner layer of the plating, the more the inside of the plating reaches the detector as shown in Fig. 6. It is utilized that a large amount is absorbed and the degree of the absorption changes depending on the composition gradient of the plating alloy.

If a sufficient amount of heat is applied to the metal plated on the two layers, the degree of complete diffusion will end up, that is, the alloy composition ratio of each metal of the alloy plating will be uniform in the inner and outer layers of the plating, and the amount of heat will be smaller than that. If you give
That is, the alloy composition ratio has a gradient in the inner and outer plating layers. Here, it is the second layer in the plating in the two-layer state before diffusion, that is, the metal plated on the outside, that has a high ratio in the outer layer portion of the plating, and the first layer has a high ratio in the inner layer portion. That is, the metal is plated inside.

In this way, for the two-layer plating applied to the linear body,
In the diffusion process caused by heating, the abundance ratio of the second-layer metal existing in the plating outer layer portion before diffusion gradually decreases and finally becomes uniform in the plating inner and outer layer portions. When secondary X-rays from each metal are detected by fluorescent X-ray analysis of gold plating, the rate at which the secondary X-rays generated from the first layer metal are absorbed by the second layer metal gradually decreases. Become. That is, the absorption is maximum in the two-layer state before diffusion, and is minimum in the complete diffusion.

Therefore, the intensity ratio of the secondary X-rays from both obtained by the fluorescent X-rays is not affected by the total amount ratio of the two-layer metal in the plating present on the linear body before the diffusion and after the alloying. Also depends on the degree of diffusion. That is, as the degree of diffusion progresses, the intensity ratio of the secondary X-rays from the plated metal applied to the first layer increases, and conversely the intensity ratio of the secondary X-rays from the plated metal of the second layer decreases.

In the present invention, the relationship between the degree of diffusion and the intensity ratio of secondary X-rays is utilized to determine the plating alloy composition gradient. That is, in a linear body plated in a two-layered state so as to have a predetermined alloy composition ratio, samples were prepared in which the diffusion degree was sequentially changed in advance, and secondary X-rays of the plating component metals were obtained by fluorescent X-ray analysis for those samples. Obtain the intensity ratio data.

For example, taking a case of thermal diffusion brass plating on a steel wire, FIG. 3 is a relational diagram showing the secondary X-ray intensity ratio with respect to the diffusion heating amount, and the composition ratio of Cu and Zn is 65%: 35% and 6
7%: For the steel wire sample with Cu plating on the first layer and Zn plating on the second layer to achieve 33%, the diffusion heating amount was A ₁ ,
A _2, A _3, A ₄ and varied, Cu two to the sum of Cu and Zn secondary X-ray intensity due to diffusion before and fluorescent X-ray analyzer obtained from brass was Tsu different about the diffusion for each heating amount It is the secondary X-ray intensity ratio (Icu / (Icu + Ixn)), but as the heating amount was increased, the secondary X from Cu plated on the first layer was increased.
The line intensity ratio is increasing. In addition, Fig. 4 shows that the alloy composition ratio was measured from the outside to the inside by atomic absorption by melting the plating sequentially from the plating surface for the brass ratio having a Cu ratio of 65% with different diffusion degree. Indicates. Also,
FIG. 5 shows the alloy phase state of the same sample measured by an X-ray diffractometer.

Then, by inputting the above data into a microcomputer, the energy dispersive X-ray fluorescence analyzer in the thermal diffusion alloy plating line of the above-mentioned continuous production plated at the same alloy composition ratio when measured under the same conditions. For linear objects, the degree of diffusion can be determined from the intensity ratio of the secondary X-rays, and the measurement result of the fluorescent X-ray analyzer is set to the target degree of thermal diffusion via a microcomputer and during continuous operation. Also, it is possible to automatically correct the fluctuation while knowing the actual degree of diffusion.

In addition, when the plating composition ratio itself changes during continuous production, that is, when the plating thickness of each metal changes in the two-layer state before entering the heat diffusion device in the above process, Because the amount of metal present is changing,
A deviation may occur in the relationship between the degree of diffusion and the intensity ratio of the secondary X-ray.

However, basically, for changes in the overall metal composition ratio,
It is considered that the intensity ratio of the secondary X-rays also varies relatively.
Therefore, even in such a case, in order to correct the deviation, a fluorescent X-ray analyzer is arranged after the plating and before the thermal diffusion, and the secondary X from each metal in the two-layer state is plated.
It is possible to obtain the target degree of diffusion with accuracy by obtaining the lines, correcting the fluctuation values through the microcomputer as needed, and transferring the corrected values to the diffusion heat quantity control unit arranged after the heat diffusion step.

The above description has described an alloy plating method consisting of two-component metals. However, even if it consists of three or more components, in the method of performing thermal diffusion after plating in multiple layers, there is a difference in the alloy composition ratio between the inner and outer plating layers depending on the degree of diffusion. Therefore, it can be performed in the same manner as the two-layer plating.

Further, the fluorescent X-ray analyzer used in the present invention may be either a wavelength dispersion type or an energy dispersion type. But,
Since it is necessary to detect two or more types of secondary X-rays at the same time from the same place, the wavelength dispersive type requires as many dispersive crystals and detectors as there are plating component metals, and the installation position is geometric. However, since the energy dispersive type can detect secondary X-rays in the entire energy range at the same time and there are few positional restrictions, the wire diameter of the present invention is 1 m.
It is more effective because it is a thin linear body with a diameter of about mφ and can be accurately analyzed even during continuous operation with minute vibrations.

Further, the secondary X-ray to be detected may have any energy level of Kα ray and Lα ray, but it may be appropriately selected according to the plating thickness, the alloy plating component, etc. from the relation of absorption.

(Embodiment) An embodiment of the present invention will be described below with reference to the drawings.

As shown in FIG. 1, the linear body 2 drawn out from the delivery reel 1 passes through a pretreatment device 3 for degreasing, washing with water, pickling, etc.
Two layers are plated through a plating bath 4 for Cu plating of the first layer and a plating bath 5 for Zn plating of the second layer, and further pass through a water washing unit 6 and a drying unit 7 before thermal diffusion. It is heat-diffused through the device 8 to form the alloy-plated linear body 9 which is continuously wound on the winding reel 10.

In the thermal diffusion alloy plating step arranged as described above, the energy dispersive X-ray fluorescence analyzer 11 is arranged near the linear body at a predetermined position after the thermal diffusion step.

The energy dispersive X-ray fluorescence analyzer 11 has its fluorescence X
The surface of the linear body 9 is irradiated with X-rays from the line generation tube 12, and the secondary X-rays from the respective metals plated with the thermal diffusion alloy on the surface of the linear body are simultaneously detected. The variation in the compositional gradient of the plating alloy alloyed by the variation in the next X-ray intensity ratio is detected, the detected value is compared with a preset reference value, and the modification value is calculated by the microcomputer 13 to obtain the modification value. Is continuously fed back to the thermal diffusion control device 14 to automatically control the amount of diffusion heat of the thermal diffusion device 8 so that the intended plating alloy composition gradient can be uniformly obtained in the longitudinal direction of the linear body.

Next, FIG. 2 shows a different embodiment, in the thermal diffusion alloy plating step having the energy dispersive X-ray fluorescence analyzer 11 similar to the above-mentioned embodiment, further after the metal plating step and before the thermal diffusion step. An energy dispersive X-ray fluorescence analyzer 15 is arranged near the linear body at a predetermined position.

The energy dispersive X-ray fluorescence analyzer 15 has its fluorescence X
The surface of the linear body 17 is irradiated with X-rays from the radiation generating tube 16, and secondary X-rays from each metal plated on the surface of the linear body in two layers are simultaneously detected. The layer state of the two-layer plating (metal deposition amount ratio) is analyzed from the intensity ratio of X-rays, and the detected value is compared with a preset reference value to calculate a modification value in the microcomputer 13.

Further, similarly to the embodiment shown in FIG. 1, the plating alloy composition gradient of each metal is analyzed from the intensity ratio of the secondary X-ray detected by the energy dispersive fluorescent X-ray analyzer 11. The detected value and a preset reference value are compared and calculated in the microcomputer 13 to obtain a modified value. Then, the modified value is corrected by the microcomputer 13 by the modified value obtained by the energy dispersive X-ray fluorescence analyzer 15, and the corrected modified value is continuously fed back to the diffusion heat control unit 14. Automatically control the amount of heat of diffusion.

The two-layer plated linear body is alloy-plated by the heat diffusion device 8 as described above, and the phase state of this alloy plating is adjusted to the intended plating alloy composition gradient.

In this manner, the desired plating alloy composition gradient can be obtained accurately and continuously without stopping the operation and uniformly in the longitudinal direction.

Conventionally, the precision of the plating alloy composition gradient has been required very strictly from the adhesiveness with rubber, and in the brass-plated steel wire for steel tire cord, for example, the Cu concentration in the outer layer portion and the inner layer portion of the alloy plating is At present, a continuous plating production is required to obtain a composition gradient of 9% with an accuracy of about ± 3% at most, but ± 1.5% if the method of the present invention is used.
It has become possible to obtain brass plating with an accuracy within the range.

(Effects of the Invention) According to the method of the present invention, fluctuations in the composition gradient of the plating alloy of the rubber-reinforcing linear body during continuous production are analyzed and corrected by an energy dispersive X-ray fluorescence analyzer or a microcomputer, and The corrected data is fed back to the diffusion heat quantity control unit, and the diffusion heat quantity is automatically adjusted moment by moment to perform heat diffusion. Can be applied almost uniformly in the longitudinal direction of the. Therefore, it is most suitable for manufacturing a steel wire of an automobile tire cord in which the precision of the plating alloy composition gradient is strictly required from the viewpoint of adhesiveness with rubber. Further, not only for thermal diffusion alloy plating that gives peculiarity to the plating alloy composition gradient like this, but also for those that always require a complete diffusion degree for plating, it is almost uniform and accurate in the longitudinal direction. It can be produced continuously. Further, in the conventional method, a great deal of labor was spent on diffusion heat quantity management, various analyses, etc., but the method of the present invention enables automatic control and improves the operating rate of the thermal diffusion alloy-plated linear body. However, it has excellent effects such as an improvement in yield and a great improvement in productivity.

[Brief description of drawings]

FIG. 1 is an explanatory view of a thermal diffusion alloy plating step of a linear body showing an embodiment of the present invention, and FIG. 2 is an explanatory view of a thermal diffusion alloy plating step of a linear body showing another embodiment of the present invention. FIG. 3 is a curve diagram showing the relationship between the diffusion heating amount and the secondary X-ray intensity ratio, FIG. 4 is a curve diagram showing the composition gradient of the plating inner and outer layer portions, and FIG. 5 is the degree of diffusion and the alloy state. The diffraction diagram and FIG. 6 are explanatory diagrams showing the degree of absorption of the calibration curve of the fluorescent X-ray analysis into the brass plating layer. 1 ... Delivery reel, 2,9,17 ... Linear body, 3 ... Pretreatment device, 4,5 ... Plating bath, 6 ... Washing device, 7 ...
Drying device, 8 ... Heat diffusion device, 10 ... Take-up reel, 1
1,15 …… Energy dispersive X-ray fluorescence analyzer, 12, 16…
… Fluorescent X-ray tube, 13… Microcomputer, 14…
… Thermal diffusion control section.

Claims (2)

[Claims] 1. A linear body in which two or more different metals are continuously divided into two or more layers for each type of metal while the linear body is running to perform plating, and then thermal diffusion is performed to form an alloy. In the continuous alloy plating method, the secondary X-rays from the respective metals subjected to the thermal diffusion alloy plating are simultaneously detected by the energy dispersive X-ray fluorescence analyzer placed at a predetermined position after the thermal diffusion step, and the secondary X-rays are Analyze the plating alloy composition gradient of each metal from the strength ratio of the above, calculate the correction value by comparing the detected value with a preset reference value, and continue the correction value to the diffusion heat quantity control unit of the heat diffusion device. A method for plating a thermal diffusion alloy on a rubber-reinforcing linear body, which is characterized by automatically controlling the amount of diffusion heat. 2. A secondary X-ray from each layer-plated metal is simultaneously detected by an energy dispersive X-ray fluorescence analyzer placed at a predetermined position after the plating process and before the thermal diffusion process, The metal adhesion amount ratio of each metal was analyzed from the intensity ratio of the secondary X-rays, the detected value was compared with a preset reference value to calculate a modification value, and the modification value was arranged after the thermal diffusion step. The thermal diffusion alloy plating method for a rubber-reinforcing linear body according to claim 1, wherein a correction value obtained by an energy dispersive fluorescent X-ray device is corrected.