CZ223396A3 - Method of anticorrosive protection of stranded cables and apparatus for making the same - 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

Method of anticorrosive treatment of stranded ropes and equipment for its implementation

Technical field

The invention discloses a novel method of treating stranded ropes comprising a layer of zinc or tin, albeit very thin, by converting this layer to an anti-corrosion insulation, without altering the mechanical properties of the strand and the stranded rope pulling device utilizing for each pair of winding rollers low speed variable speed motor.

BACKGROUND OF THE INVENTION

A large number of rope types are currently used for various types of applications. Focusing on ropes that are used for power transmission and which should be resistant to the environment in which they are installed. Examples are ropes in cable tractors for automotive windows, clutch ropes, motor wheels, etc. It can be said that current ropes, if they have good mechanical properties, are poorly corrosion resistant and vice versa.

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

Normally used braided rope is based on stainless steel fibers. Such a rope is very strong after pulling, that is, when the metal fibers are pulled, the larger the number of fibers, the smaller the diameter of the rope, because it can better bend and withstand more stresses due to friction between the stranded fibers.

This rope is suitable for pulling and although it has acceptable acceptable corrosion protection properties, it should be noted that its mechanical properties are unsuitable for applications such as power windows, clutch ropes and the like where there are minimal mechanical requirements such as is tension, friction, rotation, compression and the like.

These weak mechanical properties are mainly the result of difficulties in pulling the rope if we try 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 draw material, so if very thin fibers are to be drawn, this must be done very sensitively due to the risk of breakage of fibers that are brittle. Such a rope has no ductility, and so it is difficult to flex and poorly resist tensile stress.

Another type of wire ropes used to date with better mechanical properties than stainless steel ropes uses galvanized or electrolytically galvanized steel as the base metal, which is still tinned, usually electrolytically.

This means forming a thin layer of tin over a zinc galvanizing or electrolytic coating on steel. This tinning is carried out mostly by electrolysis, which is an expensive and complex process, the cost of which is negatively reflected in the market price of the rope.

These tinned ropes have better anticorrosive properties 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 (galvanically or electrolytically applied coating) and the initial thickness before drawing, with the maximum time to achieve corrosion resistance in the 5% Sodium Chloride Chamber (ONS) test according to DIN 50021, does not exceed 200 hours (corrosion of iron or base metal).

Such tinned ropes therefore require an expensive and slow process, since electroplating is a complex process, and also requires rinsing, neutralization and cleaning equipment, since residues of the substances used in the 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 cleaning of waste, so that two causes are the higher costs - the required equipment and the high waste of the material.

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

One type of widely used rope is a galvanized steel rope, which is no longer processed after the drawing except for residual zinc. This rope is cheaper than a stainless steel rope or tinned rope types, but it also does not sufficiently meet the requirements of the automotive industry. Depending on the type of zinc coating and the coating thickness, it is corrosion resistant when tested with a 5% sodium chloride salt spray chamber (ONS) 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 a red cut (base metal).

Other ropes that are used in the automotive sector, which are not as commonly used as those mentioned above, are ropes made of phosphated steel, zinc-free and with a partially iron core. After the braiding operation, these ropes are phosphated and have good mechanical properties but low corrosion resistance.

Resin-coated ropes also do not meet the corrosion requirements. If they are heavily bent or subjected to severe mechanical stress, the protection breaks, the surface of the coating 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, existing stranded ropes do not meet the requirements of the automotive and motor sectors in general because they are either not corrosion-resistant 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 braided ropes which solve the above-mentioned problems at low cost without requiring extensive equipment and decontamination.

This process is based on the transformation of the zinc layer on the wire surface, the coating being very thin, with the transformation of the zinc remaining after the drawing of the steel, without the deposition of other metals, organic or synthetic resins, lacquers etc. to obtain a final product with a high degree of resistance against corrosion and without significant deviations in mechanical resistance in the final stage of production by special lubrication.

Since the rope is made of galvanized steel fibers, it can be pulled without difficulty to obtain ropes with a large amount of fibers and small diameter, thus making a flexible rope with good mechanical properties that is easy to handle because it is easy to handle it does not use any subsequent electrolytic plating which would impair these properties.

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 parent 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 restore its anti-corrosion properties by means of moisture, making it ideal for maintaining the anti-corrosion properties throughout the life of the rope.

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

The chromium can be used in the hexavalent (Cr® ⁺ ) or trivalent (Cr ^ ⁺ ) state, depending on the degree of corrosion protection required, as Cr ^ ⁺ provides a longer lifetime under the same conditions than a Cr- treated wire. ⁺ . However, there are companies that do not accept products with Cr ^ ⁺ in their facilities and therefore this procedure allows these two variants of rope treatment.

The method can be applied to any base material that can be coated with zinc, for example, galvanized or electrolytically coated steel.

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

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

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

a method that can

All these steps produce a rope that:

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

- has numerous applications in salty 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,

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

- is less contaminating,

- has anticorrosive properties that are retained for a long time after mechanical stress for the lifetime.

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

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

This towing system is equipped with a speed control device for each engine, so that if the rope on one of the rollers is overloaded or in the event of a fault, the engine speed is increased enough to equalize the voltage and the working speed is adjusted.

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

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is better illustrated by the following figures:

Giant. 1: Diagram of the procedure for the treatment of braided rope

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

Giant. 3 Cross section of winding rollers with draw system including counterweight.

Giant. 4 Detail of the device for detecting deviations in rope tension.

DETAILED DESCRIPTION OF THE INVENTION

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

The process has several phases such as degreasing, which takes place in a detergent tank or similar agent 10 equipped with a dryer 11 at the outlet and the rope goes to a second neutralization tank 3, then to a chrome bath in tank 4 with another dryer 12 and a drying stage 13, after which the insulation 18 is finally applied and further drying 14 and drying 15 are carried out.

The length of time the rope must remain in each phase is not the same. Since, for economic reasons, it is preferable that all cylinders 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 coil or cylinder 6. FIG. 2 shows two grooved rollers in whose grooves the cable 8 is guided.

On the other hand, it is preferred 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 parts 19, which form points through pins 20, connecting the support parts with two graphite teflon carriers 17, which allow some variation in its 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 the rollers 6 can be extended if they need to be replaced, cleaned, a new rope introduced, etc.

In the first stage of the method, the rope comes from the bobbin and is immersed in a tank 7, where there is a double roller 6 on which the rope is wound below the level of degreasing liquid 10 so that the rope 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 can be carried out with neutral emulsifiers, detergents or preferably with slightly alkaline degreasing agents. This phase can be carried out by immersing the rope wrapped on the roller 6 in a tank 1 or alternatively by spraying the rope 1 with these liquids. Spraying may precede or completely replace the soaking phase.

The rope emerging from the first tank 7 is dried by a blower 11 by blowing, drying or any known method and continues through the elements that keep it in tension and guide it through traps 9, rollers, etc. to the second wash tank 2 where it is rinsed to completely remove any residual impurities or degreaser 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 subsequent 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 purpose. At least one roller 6 for guiding the bath cable is also used in this phase. The neutralizing agent may be a dilute acid such as nitric, hydrochloric, sulfuric, etc., or suitable acid salts of appropriate concentration.

In the fourth phase, the cable is treated with a chrome-plating bath in tank 4. For this purpose, a bath containing trivalent chromium (Cr ³⁺ ) or hexavalent chromium (Cr ⁶⁺ ) is used, depending on the properties required.

Hexavalent chromium provides significantly better corrosion protection than trivalent, but some companies do not admit hexavalent chromium on their equipment and therefore both options apply. 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 10 g / l.

2.5 at a residence time of 10 to 120 seconds in this phase.

If the bath composition changes from Cr ³⁺ to Cr ³⁺ or vice versa, it is only necessary to rinse the feeding bath vessel or tank 4 and fill it with the desired liquid. The process can also be performed with two ropes extending from the neutralizing bath, so that one of them is fed into the tank and Cr3 ⁺ to the ^second-CR® reservoir so that at one stage is applied, two different types of anti-corrosive coating.

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 exit of the degreasing bath of the tank. After wiping, the rope goes to the drying stage 13 where all or any remaining moisture is removed by heating in a hot air stream or preferably by induction.

This is followed by the phase of the insulation layer on the rope in tank 5, where the rope wound on a double grooved cylinder 6 passes through a hot aqueous solution at a temperature between 60 and 80 ° C of a silica compound which reacts with the chromate layer in alkaline at concentrations between 10 and 50 g. liter and pH between 10.5 and 12 to form a zinc, chromate and silicon (SiO2) complex, whereby after the subsequent drying, the anti-corrosion layer is finally treated. The time required for this phase varies from 20 to 240 seconds.

The process does not produce any chromium-silicon contamination or contamination, so it is not necessary to purchase expensive disposal devices, which is valuable because chromium is highly toxic.

The last step of the process is drying 12 and drying 13 of a similar type as in the preceding steps (12 and 13).

The anticorrosive layer consists of 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, a lubrication phase can be added, depending on the expected mechanical load. If the rope is to be resistant to abrasion or friction when the rope, the fibers move towards each other, when 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 residence time according to the purpose of use of the rope, whereupon the uncapped oil is collected.

The lubricant may preferably be molybdenum sulfide or other lubricant, organic or synthetic, 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 may be added during the chromium (III) chromate phase 3 as well as the silicon compound solution, which may slightly dye the product to any color or shade, thereby distinguishing the process. Blue, green and red are best. This coloring does not affect the chemical reactions or the final achieved parameters.

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

The speed of movement of the rope is normally constant in a continuous procedure, the residence time in the individual baths or phases depends on the number of turns by which the rope is wrapped around the roller 6 at that stage. The speed at which the rope is drawn can be adjusted and adjusted in each individual case depending on the parent metal material, the desired thickness and quality of the anticorrosive 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 required 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 and removed into and out of the respective bath.

The rope extends and is guided tangentially to the dryer 22, the drain 23, where it lies on another feeder 24, which is rotatably and counterbalanced 25 mounted on a lever 26 coupled 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 changes and sends a signal to the motor 30 that drives the rollers.

The system operates very simply and operates as follows: when the process is started, all motors 30 are switched on at the same time, so that the movement of the rope 6 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, if not wound, to the next stage. This rope 8 is wound by means of threads on the rollers 6 in the respective bath.

The rope 8 leaves the lance tangentially and goes towards the drying tube 22 through which the air stream 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 exits.

After the drying 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 cylinder 6, a wire 3 is guided over 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 control the tension of the rope.

If, for any reason, the rope becomes loose, the voltage detector 24 is moved by the counterweight 25, in this case down, causing the manipulator 28 formed by the bars 9, 10 to rotate by a certain deflection which projects into the surface 31 and thereby into the detector 29. which is preferably analogue. 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 rod 27 and the manipulator 28 to the detector 29, which returns to its initial position and cancels the engine speed reduction signal 30, which then returns to its original speed.

Analogously, if the rope 13 becomes too taut, a counter-control action occurs via the lever 26, the rod 27 and the manipulator 28 to the detector 29 and a signal to the motor 30. The speed of the motor 30 is accelerated until the excess voltage of the cable 8 has disappeared.

This apparatus is equipped with a roll assembly for each phase or for each individual bath throughout the process.

The treatment is suitable (and further multiplies the corrosion resistance) for stranded wires, the surface of which is treated with a zinc alloy, such as zinc-iron, zinc-nickel, etc., electroplated.

In addition, the treatment is perfectly suitable for batch processes where a stretched rope with zinc layer residues, galvanized or otherwise zinc treated, is mechanically or similarly transferred on hollow coils and immersed in the described baths in the described phases, with analogous reactions forming a coating with the anticorrosion described above. properties.

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

Claims (11)

PATENT CLAIMS A method of anticorrosion treatment of stranded ropes, in which the base metal wire is first coated with a zinc layer, characterized in that after stranding and drawing it is formed by degreasing, washing, neutralizing, chromium plating, washing, insulation and drying phases. they can be performed in continuous or discontinuous devices. Method of anticorrosion treatment of stranded ropes according to claim 1, characterized in that in the continuous process the second washing is replaced by drying and / or drying. A method for the anticorrosion treatment of stranded ropes according to any one of the preceding claims, characterized in that the drying is carried out by blowing or by mechanical absorption methods or other known methods, wherein the excess removed material is returned to the unit from which it has been removed. there is no material loss. A method for the treatment of stranded ropes according to claims 1 and 2, characterized in that the drying consists of evaporating the water contained in the rope surface layers without reducing them, preferably by using an induction system, compressed air or other known for this purpose. methods. Method for the anticorrosive treatment of stranded ropes according to claim 1, characterized in that a lubricating phase, depending on the operating conditions for which the rope is to be considered, is further included in the last phase with oil preferably based on molybdenum sulphide or other organic or synthetic an oil suitable for this purpose. 6. A method of anticorrosion treatment according to claim 1, characterized in that the baths are equipped with rollers, drums or known systems for each bath, each of which has a series of grooves formed in the direction of their rotation from the outside. 7. The method of anticorrosive treatment of stranded ropes according to claims 1 and 6, characterized in that the time the rope remains in the individual baths is set by the number of turns through which the rope winds in the grooves of the corresponding roller. 8. The method of anticorrosive treatment of stranded ropes 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 while passing through different tanks and channels on drums or rollers. 9. A method according to claim 1, wherein in the chromating phase, a dye can also be applied together with the trivalent chromium without affecting the chemical reactions or the final results. 10. A method of anticorrosion treatment of braided ropes and towing devices, characterized in that the method uses a towing device and comprises a voltage detector or a tension detector on its path to each drum in each phase or bath, said detector having an adjustable a voltage regulator, a lever with a manipulator bar attached, and a relative position detector of the manipulator portion so that any deviation in that relative position causes a signal to be sent to the motor whose speed is adjusted by this signal until the rope voltage is at the correct value. 11. The method of anticorrosion treatment of stranded 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 regulated by varying the motor speed in each respective phase where the voltage deviation occurs. .