SK101096A3 - Anticorrosive treatment process for braided cables and drive system - Google Patents

Abstract

The anticorrosive treatement process for braided cables and drive system comprises, starting from a braided cable with a layer of residual zinc originating from the zinc deposition or galvanisation of the wire which has subsequently been drawn and braided although this layer remaining in the threads or filaments of the cable is very thin, without deposition of metal or organic or synthetic resin, etc. in order to obtain a final product having a high grade of resistance to corrosion without alteration of the mechanical behaviour. This process comprises the following steps: degreasing, dripping, washing, neutralisation, chromatization, dripping and washing, sealing, dripping and drying; the second washing can be eliminated and, in certain cases it can be proceeded subsequently to a last lubrication step. The drive system is based on independent variable and self-controllable motors, each connected to a reel at each step of the process. The system comprises for each motor an assembly consisting of an arm, a counterweight and an analog sensor for the speed regulation of the motor when the tension of the cable varies. <IMAGE>

Description

The invention relates to a novel method of treating entangled ropes comprising a zinc or tin layer, albeit very thin, by converting this layer into corrosion-proof insulation, without altering the mechanical properties of the rope and the twisted rope pulling device using a low speed for each pair of winding rollers variable speed motor.

BACKGROUND OF THE INVENTION

At present, many types of ropes are used for different types of applications. If we focus only on ropes that are used to transmit power and which should be resistant to the environment in which they are located, such as rope tractors for car windows, clutch cables, motor wheels, etc., it can be said that currently ropes, when they have good mechanical properties, are poorly resistant to corrosion and vice versa.

These ropes are installed in sets or assemblies whose other parts have a longer service life because they are not subject to the effects of corrosion and the mechanical effects to which they are exposed. For this reason, these ropes generally require a longer lifetime, so that they do not need to be changed more frequently than other parts.

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The braided rope used is based on stainless steel fibers. Such a rope is very strong after pulling, that is, when the metal fibers are pulled, a larger number of fibers, a smaller final rope diameter, as it can better bend and resist greater stresses due to friction between the braided fibers.

This rope is suitable for use after pulling and although it has acceptable anti-corrosion properties, it should be noted that its mechanical properties are unsuitable for applications such as window door controls, clutch ropes and the like where there are minimal mechanical requirements such as pulling , friction, rotation, compression and the like.

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These weak mechanical properties are mainly due to the difficulties of pulling the rope when attempting to do it with a large number of fibers, because, as already mentioned, the larger the number of fibers in the smaller final diameter, the better the mechanical properties of the rope.

Stainless steel is a very hard, difficult to pull material, so if very thin fibers are to be drawn, it is very delicate due to the risk of breakage of fibers that are brittle. .This rope has no ductility and is therefore difficult to flex and poorly withstand tensile stress.

Another type of currently used ropes with better mechanical properties over stainless steel ropes uses galvanized or electrolytically galvanized steel as the base metal, which is still tinned, mostly electrolytically.

That is, to form a thin layer of tin over a zinc galvanizing or electrolytic coating on steel. This tinning is usually carried out by electrolysis, which is an expensive and complex process, the cost of which is negatively reflected in the commercial value of the rope.

Such tinned ropes improve the rust resistance of the parent metal, but do not meet the requirements and needs of certain industries, such as the automotive industry. The corrosion protection is still weak and depends on the type of galvanizing (galvanic or electrolytically applied coating) and the initial thickness before drawing, with the maximum time to resist corrosion in the 5% Sodium Chloride (ONS) salt test according to DIN 50021 , does not exceed 200 hours (corrosion of iron or base metal).

Such a tinned rope therefore requires an expensive and slow process, since the electroplating is a complex process, and also requires a device for rinsing, neutralization and cleaning, since the residues of the substances used in this process are highly harmful and require processing before they can be removed. to waste. It also follows that some of the substances used in this process are lost in the neutralization and purification of the waste, so that two causes cause higher costs - the required equipment and the high waste of the material.

Stainless steel base metal ropes or tinned ropes made by any method are not stable on the market and therefore their price fluctuates because these materials are produced by few companies and their delivery cannot always be guaranteed.

One type of widely used rope is a galvanized steel rope which, after drawing, is no longer processed except for residual zinc. This rope is cheaper than stainless steel ropes or tinned rope types, but also does not sufficiently meet the requirements of the automotive industry. Depending on the type of galvanizing and coating thickness, corrosion resistance is achieved in the 5% Sodium Chloride Salt Chamber (ONS) test according to DIN 50021 between 24 and 72 hours (corrosion of iron or base metal).

The corrosion test in an industrial environment (climate chamber, 2 liters of SO2) according to DIN 50.018 does not pass the first cycle without the formation of red rust (base metal).

Other ropes that are used in the automotive sector that are not as commonly used as those mentioned above are ropes made of phosphated steel, without zinc and with a partially iron core. After the braiding operation, these ropes are phosphated to obtain good mechanical properties, but poor corrosion resistance.

Resin-coated ropes also do not meet the corrosion requirements. If they are very bent or subjected to severe mechanical stress, the protection breaks, the coating surface peeling off, the cracks formed promote shear stress and cause greater surface damage.

Plastic coated ropes should not be manufactured for use under severe mechanical conditions as they are deplastified.

Another type of rope used in the automotive sector, but without anti-corrosion properties, is copper or tinned rope used in tires.

Overall, it is possible to conclude that the braided cables of the prior art do not meet the requirements of the automotive and motor sectors in general, because either they are not sufficiently resistant to corrosion or, if they are, have inferior mechanical properties and are more expensive.

SUMMARY OF THE INVENTION

Using the process according to the invention, it is possible to produce twisted ropes which solve the above-mentioned low cost problems without requiring extensive equipment or decontamination.

This procedure is based on the transformation of the zinc layer on the surface of the wire, the latter

The coating is very thin, with the transformation of the zinc remaining after the steel drawing, without the deposition of other metals, organic or synthetic resins, lacquers, etc., resulting in a final product with a high degree of corrosion resistance and without significant variations in mechanical resistance production by special lubrication.

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Since the rope is made of galvanized steel fibers, it can be pulled without difficulty to obtain ropes with a large number of fibers and a small diameter, thus making a flexible rope with good mechanical properties that is easy to handle because no subsequent electroplating, which would impair these properties, is used.

In addition, the chromium-silicon coating formed on the surface of the zinc layer forms a microcrystalline coating based on the salts of zinc, iron, chromium and silicon, which largely prevents the formation of corrosion products on the base metal, even under considerable mechanical stress in a corrosive environment. This hard, friction-resistant layer is a migratory layer, which means that after damage it can partially recover its corrosion resistance properties by means of moisture and is thus ideal for maintaining the corrosion resistance throughout the life of the rope.

It has been found that the corrosion protection of this stranded rope is maintained for a minimum of 240 to 800 hours in the salt mist chamber test according to DIN 50021, depending on the zinc layer, the base material and the type of chromate applied or formed.

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Chromium can be used as hexavalent (Cr) or trivalent (Cr), depending on> 6 · 6+ what degree of corrosion protection is required, since Cr under the same conditions provides a longer lifetime than a Cr ^3- treated rope. However, there are companies that do not accept 6 +.

Cr with their equipment and therefore this procedure allows these two variants in the treatment of the rope.

The method can be used on any base material that can be coated with zinc, for example, galvanizing or electrolytically galvanizing steel.

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Thus, according to the invention, it is a process with high anti-corrosion efficiency, due to the chromium-silicon layer, which is economical and simple and does not require a deposition phase by electroplating, which makes other processes more expensive and complicated. In the process according to the invention, there are small variations in mechanical properties, the product obtained is flexible and easy to handle, and there is no material loss during the coating. In a continuous process, the washing phase may optionally be omitted, eliminating possible contamination and reducing costs, by drying and / or drying (by blowing or mechanical absorption of bath residues) or by another known method that may be used.

All chrome-silicon material remains in the process without waste or contamination of the working environment.

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Finally, depending on the end use of the braided rope, a lubrication phase may be employed, preferably with molybdenum sulphide or other organic or synthetic lubricant.

All these steps produce a rope that:

- means lower maintenance costs for the equipment in which it is used,

- has many applications in salt and highly corrosive environments,

- is economically advantageous because of its long service life, since the mechanical properties are maintained for the duration of the real tests of these types of ropes,

- is lubricable and colorable in the same process or in a subsequent process,

- is less contaminating,

- has anticorrosive properties which are largely retained during mechanical durability.

The rope 8 goes through the phases of the process in that it is pulled by a system based on the use of a motor, preferably electric, which is independent for each phase of the process. At the beginning, these motors rotate at the same speed, so there is no significant rope tension from the end of the process. This tension increases as the process is extended.

The use of these mechanisms in the rope shifting means results in a significant reduction in its tension, as the traction forces are applied at all stages of the process, and moreover, this force is not based on towing but instead rotary drums or rollers having a large pulling force, so much better power distribution and less rope tension.

This towing system is equipped with a device for controlling the speed of each engine, so that if the rope on one of the rollers is too high, or in the event of a failure, the engine speed is sufficiently increased to equalize the voltage and the working speed is adjusted.

The control device comprises a counterweight, a lever arm with attached rod / lever, further preferably an analog detector, a speed change controller, preferably of the vertical type, and the motor itself.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is better illustrated by means of the following figures:

Fig. 1: Schematic of the process of treatment of braided rope

Fig. 2: View of winding rollers with motor, levers and control device in longitudinal direction.

Fig. 3 Cross section of winding rollers with towing system including counterweight.

Fig. 4 Detail of the device for detecting cable tension variations.

DETAILED DESCRIPTION OF THE INVENTION

As shown in FIG. 1, tanks 1, 2, 3, 4, 5 (five in this embodiment) are used. Any of them may be replaced in another embodiment. In each tank there is a double grooved cylinder 6, provided with grooves 7 in which the rope 8 is wound and unwound. This cable is guided through the inserters and traps 9.

This process has several phases, such as degreasing, which is carried out in a detergent or similar agent tank 10 equipped with an outlet dryer 11 and the rope goes to the second neutralization tank 3, then to a chrome bath in tank 4 with another dryer 12 and phase drying 13, after which the insulation is applied and further drying 14 and drying 15 are carried out.

The length of time during which the rope must remain in each phase is not the same. Since it is advantageous for economic reasons that all rollers 6 are identical and the speed should also be the same, the residence time is set by the number of turns through which the rope is guided on each spool or roll 6. FIG. 2 shows two grooved rollers in grooves 7 in which the rope 8 is guided.

On the other hand, it is preferable that the rollers 6 are hollow because of their low weight and have grooves through which the rope 8 passes. These coils or rollers 6 rotate on two loosely supported support pieces 19 which form points connecting the support pieces with two via pins 20. graphite teflon carriers 17 which allow some variation in their bearing 21 in the bodies 16 which are connected at the top to all the bodies of the other rollers, so that by extending this structure all rollers 6 can be extended if they need to be replaced, cleaned, new rope, etc.

In the first stage of the process, the rope comes from the spool and is immersed in a tank 1 where there is a double roller 6 on which the rope 8 is wound below the surface of the degreasing liquid 10 so that the rope 8 is cleaned of all dirt and can be treated. The liquid 10 can be any of the commonly used liquids for this purpose, no particular type is required, only the optimum temperature of this bath is between room temperature and 90 ° C and a time between 30 and 180 seconds.

Degreasing may be accomplished with neutral emulsifiers, detergents or preferably weakly alkaline degreasers. This phase can be accomplished by immersing the rope wrapped on the roller 6 in the tank 1 or alternatively by spraying the rope 8 with these liquids.

Spraying may precede or completely replace the soaking phase.

The rope emerging from the first tank I is dried by a blower Π by blowing, drying or any known method and then continues through the elements which keep it in a tensioned state and guide it by means of traps 9, rollers, etc. to a second rinse tank 2, where it is rinsed to remove completely any residual impurities or degreasing agent from the previous step.

This second washing phase can be replaced by showering or spraying, achieving the same effect and saving the tank 2 with the respective cylinder 6. Wastes from both washing stages are biodegradable so that they do not constitute a source of environmental contamination.

The following neutralization phase in the tank 3 ensures that traces of degreasing agents are also removed and any reagent with appropriate properties is used for this. At least one roller 6 for guiding the rope through the bath is also used in this phase. The neutralizing agent can be diluted acids such as nitric, hydrochloric, sulfuric, etc. or suitable acid salts of appropriate concentration.

In the fourth phase, the rope is treated with a chrome bath in tank 4. A 3 + 6+ pollen containing Cr (III) or hexavalent (Cr) chromium is used, depending on the properties required.

Hexavalent chromium provides significantly better corrosion protection than trivalent, but some companies do not allow hexavalent chromium on their installations and therefore both options apply in this case. The temperature should be from room temperature to 40 ° C at a hexavalent chromium concentration of 1 to 10 g / l and a pH of 1 to 2.5 at a residence time of 10 to 120 seconds at this stage.

3+ 6+

If the bath composition changes from Cr to Cr or vice versa, it is only necessary to rinse the vessel or tank 4 of the chrome bath and fill it with the desired liquid. The method can also be carried out with two ropes starting from the neutralization bath such that one

3+ 6+ of these are fed into the Cr tank and the other into the Cr tank, so that two different types of anti-corrosion coatings are applied in one step.

After the chromating phase in the tank 4, the rope is dried with a dryer 12, in the same manner as in the previous drying with a dryer 11 at the outlet of the degreasing bath of the tank 1. After wiping, the rope goes into the drying phase 13 where any possible remaining moisture is removed by heating in a hot air stream or preferably by induction.

This is followed by the formation of an insulating layer on the rope in the tank 5, where the rope wound on the double grooved cylinder 6 passes through a hot aqueous solution having a temperature of between 60 and 80 ° C silica compound which reacts with the chromate layer in alkaline at concentrations between 10 and 50 g / pH between 10.5 and 12 to form a complex of zinc, chromate and silicon (SiO ₂ ), thereby finally forming, after subsequent drying, an anti-corrosion layer. The time required for this phase ranges from 20 to 240 seconds.

There are no chromium-silicon contaminants or contamination in the process, so it is not necessary to procure expensive equipment for their disposal because chromium is highly toxic.

The last step of the process consists of the sludge drying 12 and the drying 13 of a similar type as in the previous steps (12 and 13).

The anticorrosive layer is a microcrystalline layer based on zinc, iron, chromium and silicon, which largely protects against corrosion of the parent metal even under conditions of high mechanical stress in a corrosive environment.

After the last stage, the lubrication phase can be added, depending on the expected mechanical load. If the rope is to be resistant to abrasion or friction when rotating the rope, the fibers to each other, pulling, winding, etc., lubrication should be included. In this case, the rope goes to another tank 18, in which it is brought by spraying or immersion into contact with the oil at a suitable temperature and a residence time according to the purpose of the rope, whereupon the uncapped oil is collected.

The lubricant may preferably be molybdenum sulfide or other lubricants, organic or synthetic, which are suitable for this purpose.

Finally, if the rope is lubricated, drying and drying can be added after this lubrication.

Optionally, an appropriate aniline-type dye can be added during the trivalent chromate chromate phase as well as in the silicon compound solution, which may slightly discolour the product to any color or shade, which can distinguish the process. Blue, green and red are most suitable. This coloring does not affect the chemical reactions or the endpoints achieved.

After all stages of the treatment process, the rope can be wound up for commercial purposes and use.

The speed of the rope movement is normally constant in a continuous process, the residence time in the individual baths or phases depends on the number of turns by which the rope is wound around the roller 6 at that stage. The speed at which the rope is pulled can be adjusted and adjusted in each individual case depending on the base metal material, the desired thickness and the quality of the corrosion-resistant coating and the diameter of the rollers. The figures show the rollers 6 which are normally located inside the bath in the tank. The rope 8 is wrapped around these rollers with a sufficient number of turns to achieve the necessary residence time in each bath.

The rollers 6, as well as other elements, are housed in an assembly that is vertically movable to allow them to be inserted or removed into or out of the respective bath.

The rope extends and is guided tangentially to the dryer 22, discharging 23, where it lies on another feeder 24 which is rotatably counterbalanced 25 mounted on a lever 26 connected movably to a rod 27 which acts as a voltage sensor connected via a lever or arm 28 s. a detector 29 which is located at its end and which is sensitive to variations in distance and sends a signal to the motor 30 that drives the rollers.

The system works very simply and operates as follows: when the process is started, all motors 30 are switched on simultaneously, so that the movement of the rope 8 is synchronized in all phases.

Advantageously, a separate motor drive may be used for each phase of the process.

This method of displacement allows good pulling of the rope which is unwound from the roller to the next phase. This rope 8 is wound by threads on the rollers 6 in the respective bath.

The rope 8 leaves the upper roller tangentially and goes towards the drying tube 22 through which the air flow passes to the rope and blows away any liquid that has been retained on the rope back to the same tank from which the rope exited.

After the desiccant tube 22, the rope passes through the drain 23 to the cylinder of another bath. In this part, between the drain 23 and the other roller 6, the cable 8 is guided through the feeder 24.

The drain 23 may be formed as any type of rope voltage detector 8 at this point. Said voltage detector 24 is connected to a lever 26 movably mounted on a rod 27 which can move its axis.

This lever 26 can be loaded with a counterweight 25 which provides a signal to regulate the rope tension.

If, for any reason, the rope 8 becomes free, the voltage detector 24 is moved by the counterweight 25, in this case downwards, causing the manipulator 28 formed by the rods 9, W to rotate by a certain deflection which is reflected on the surface U and thereby into the detector. 29, which is preferably analog. The detector 29 sends a speed-reducing signal to the motor 30 when the voltage is reduced before the rope voltage is again adjusted to the required value. The feeder 24 goes up and sends a signal through the lever 26, the arm 27 and the manipulator 28 to the detector 29, which reaches the starting position and abolishes the engine speed reduction signal 30, which in turn returns to its original speed.

Analogously, when the rope 8 begins to overstretch, the lever 26, the rod 27 and the manipulator 28 on the detector 29 and the signal to the motor 30 cause a reverse control intervention. The speed of the motor 30 is accelerated until the excess tension of the cable 8 has disappeared.

This equipment is equipped with a roll assembly at each stage or for each individual bath throughout the process.

The treatment is suitable (and further multiplies the corrosion resistance) for application to stranded wires whose surface is treated with a zinc alloy, such as zinc-iron, zinc-nickel, etc., coated with galvanic (electroplating).

Moreover, the treatment is also perfectly suited for discontinuous processes, when a stretched rope with zinc layer residues, galvanized or otherwise zinc treated, is transferred mechanically or similarly on hollow coils and immersed in the described baths in the described phases, whereby a coating with higher by the mentioned anticorrosive properties.

Having explained the nature of the invention and one particular embodiment in practice, it is to be appreciated that the method of the invention can be modified both in terms of the shape, the materials and the layout of the parts both overall and in individual parts, but this does not entail a substantial change in the properties.

Claims (11)

PATENTOVÉNÁROKY A method for the corrosion treatment of entangled ropes, in which the base metal fiber is first coated with a zinc layer, characterized in that after entanglement and drawing it consists of degreasing, washing, neutralizing, chromium, washing, isolation and drying phases can be performed in continuous and discontinuous facilities. Method for the corrosion treatment of entangled ropes according to claim 1, characterized in that in a continuous process the second washing is replaced by drying and / or drying. Method for the corrosion treatment of entangled ropes according to one of the preceding claims, characterized in that the drying is carried out by blowing or mechanical absorption methods or other known methods, wherein the excess material is returned to the unit from which it has been removed so that no loss of material. Method for the treatment of stranded ropes according to claims 1 and 2, characterized in that the drying consists of evaporating the water which the surface layers of the rope contain without reducing the layers, preferably by using an induction system, compressed air or otherwise for these. for the known method. Method for the anticorrosive treatment of strands according to claim 1, characterized in that a lubricating phase is added after the last phase, depending on the operating conditions for which the rope is considered, with an oil preferably based on molybdenum sulphide or other organic or synthetic oil suitable for this purpose. 6. The method of claim 1, wherein rollers, drums or known systems are used in each stage to soak the ropes in individual baths, each of which is provided with a series of grooves formed in the direction of rotation from the outside. Method for the corrosion treatment of entangled ropes according to claims 1 and 6, characterized in that the time during which the rope remains in the individual baths is set by the number of turns by which the rope winds in the grooves of the corresponding roller. 8. The method for treating cores according to claim 1, characterized in that the continuous mode of operation uses a constant feed rate due to the fact that the rope is pulled from the end and passes through different tanks and channels on the drums or rollers. A method for the corrosion treatment of entangled ropes according to claim 1, characterized in that a dye can also be applied together with the trivalent chromium in the chromating phase without affecting the chemical reaction or the final results. 10. A method of corrosion treating strands and a pulling device therefor, characterized in that the method comprises a pulling device and comprises a detector of tension or relief of rope tension on its path to each roller in each phase, said detector having an adjustable voltage regulator , a handle with a connected rod and a manipulator, and a detector of relative position changes of the manipulator portion, so that any deviation in this relative position causes a signal to be sent to the motor whose speed is adjusted by this signal until the rope tension is at the correct value. Method for the corrosion treatment of entangled ropes according to the preceding claims, characterized in that each phase or bath has a control device independent of the others, which means that the rope voltage is controlled by varying the motor speed in each respective phase, where the rope voltage variation effect.